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<!-- DFS Xcelerate Instance Document - http://www.dfsco.com/financial-services/ -->
<!-- Version:  6.23.6 -->
<!-- Round: 6 -->
<!-- Creation date: 2018-05-09T16:53:00Z -->
<!-- Copyright (c) 2017 Donnelley Financial, LLC. All Rights Reserved. -->
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  <us-gaap:BasisOfAccountingPolicyPolicyTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_7F3F5645-44BC-4C4A-B5A6-A7293A759EB4_1_0">&lt;div&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Basis of Presentation&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The condensed consolidated balance sheet as of March&amp;#xA0;31, 2018,
 the condensed consolidated statements of operations for the three
 months ended March&amp;#xA0;31, 2018 and 2017, the condensed
 consolidated statements of cash flows for the three months ended
 March&amp;#xA0;31, 2018 and 2017 and the condensed consolidated
 statement of stockholders&amp;#x2019; equity as of March&amp;#xA0;31, 2018
 are unaudited. The unaudited condensed consolidated financial
 statements have been prepared on the same basis as the annual
 consolidated financial statements and reflect, in the opinion of
 management, all adjustments of a normal and recurring nature that
 are necessary for the fair presentation of the Company&amp;#x2019;s
 condensed consolidated financial statements included in this
 report. The condensed consolidated financial data disclosed in
 these notes to the condensed consolidated financial statements
 related to the three-month periods are also unaudited. The
 condensed consolidated results of operations for the three months
 ended March&amp;#xA0;31, 2018 are not necessarily indicative of the
 results to be expected for the year ending December&amp;#xA0;31, 2018,
 or for any other future annual or interim period. The condensed
 consolidated balance sheet as of December&amp;#xA0;31, 2017 included
 herein was derived from the audited consolidated financial
 statements as of that date. These condensed consolidated financial
 statements should be read in conjunction with the Company&amp;#x2019;s
 audited consolidated financial statements included in the
 Company&amp;#x2019;s Annual Report on Form &lt;font style="white-space:nowrap"&gt;10-K&lt;/font&gt; for the year ended
 December&amp;#xA0;31, 2017, filed with the SEC on February&amp;#xA0;27,
 2018.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:BasisOfAccountingPolicyPolicyTextBlock>
  <us-gaap:ConcentrationRiskCreditRisk contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_9C611D6A-A490-4125-904E-4C99E809F12C_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Concentrations of Credit Risk&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Financial instruments that subject the Company to significant
 concentrations of credit risk consist of cash, cash equivalents and
 restricted cash. All of the Company&amp;#x2019;s cash, cash equivalents
 and restricted cash are held at financial institutions in the
 United States and Canada that management believes to be of high
 credit quality. Deposits held in the United States and Canada with
 these financial institutions exceed federally insured limits.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The primary focus of the Company&amp;#x2019;s investment strategy is to
 preserve capital and meet liquidity requirements. The
 Company&amp;#x2019;s investment policy addresses the level of credit
 exposure by limiting the concentration in any one corporate issuer
 and establishing a minimum allowable credit rating.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:ConcentrationRiskCreditRisk>
  <us-gaap:CashAndCashEquivalentsPolicyTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_38C77C24-D92C-4BB9-B909-A165E7A4122F_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Cash and Cash Equivalents&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company considers all highly liquid investments with an
 original maturity of three months or less from the date of purchase
 to be cash equivalents. Cash and cash equivalents consist primarily
 of funds invested in readily available checking and savings
 accounts and highly liquid investments in money market funds.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:CashAndCashEquivalentsPolicyTextBlock>
  <us-gaap:CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8FC11E24-CF30-4FEC-80AF-F253A0B4EEA2_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Restricted Cash&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Restricted cash, which consists of funds invested in a money market
 fund, represents collateral for a corporate credit card facility.
 Restricted cash at December&amp;#xA0;31, 2017 also included security
 deposits required for a facility lease that expired in February
 2018.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy>
  <us-gaap:CommitmentsAndContingenciesDisclosureTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_9D42AABB-D6C2-4611-B132-1A5507972AA5_1_0">&lt;div&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;&lt;b&gt;6.&lt;/b&gt;&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;&lt;b&gt;Commitments and
 Contingencies&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;License Agreements&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In September 2016, the Company entered into an exclusive license
 agreement with CRT Pioneer Fund LP (CPF) for worldwide rights,
 &lt;font style="white-space:nowrap"&gt;know-how&lt;/font&gt; and materials to
 develop SRA737, a small molecule inhibitor targeting Chk1, a
 promising therapeutic target to treat cancer. Pursuant to the
 agreement, the Company made a &lt;font style="white-space:nowrap"&gt;one-time&lt;/font&gt; upfront payment of
 $7.0&amp;#xA0;million to CPF in October 2016 and paid $2.0&amp;#xA0;million
 to CPF in January 2017 for the successful transfer of two ongoing
 Phase I clinical trials. The expense related to these payments was
 included in research and development for the year ended
 December&amp;#xA0;31, 2016. Additional milestone payments of up to an
 aggregate of $319.5&amp;#xA0;million may become payable to CPF upon the
 achievement of certain developmental, regulatory and commercial
 milestones, and will be accrued once they are considered probable
 of occurring. In addition, the Company is required to pay CPF, on a
 &lt;font style="white-space:nowrap"&gt;&lt;font style="white-space:nowrap"&gt;product-by-product&lt;/font&gt;&lt;/font&gt; and
 &lt;font style="white-space:nowrap"&gt;&lt;font style="white-space:nowrap"&gt;country-by-country&lt;/font&gt;&lt;/font&gt; basis, tiered
 high single-digit to low double-digit royalties on the net sales of
 any product successfully developed.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In May 2016, the Company entered into an exclusive license
 agreement (Carna License Agreement) with Carna Biosciences, Inc.
 (Carna) for worldwide rights to develop and commercialize SRA141, a
 small molecule kinase inhibitor targeting Cdc7. In exchange for
 this exclusive right, the Company paid Carna an upfront payment of
 $0.9&amp;#xA0;million in June 2016. The Company will be required to pay
 Carna milestone payments of up to an aggregate of
 $270.0&amp;#xA0;million upon achievement of certain developmental,
 regulatory and commercial milestone events, which will be accrued
 once they are considered probable of occurring. As of
 March&amp;#xA0;31, 2018, the Company had not recorded any milestone
 payments to Carna. In addition, the Company is required to pay
 Carna tiered single-digit royalties on net sales of product
 candidates (as defined under the Carna License Agreement).&lt;/p&gt;
 &lt;p style="font-size:1px;margin-top:18px;margin-bottom:0px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Lease Agreements&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In February 2015, the Company entered into an operating lease
 agreement to sublease office space in Vancouver, Canada. Under the
 terms of the agreement, the Company issued a letter of credit to
 the sublessor on closing, which was collateralized by a restricted
 deposit. The operating lease agreement together with the restricted
 deposit expired on February&amp;#xA0;2018. In June 2017, the Company
 entered into a new operating lease agreement to continue leasing
 the office space in Vancouver, Canada commencing March&amp;#xA0;1,
 2018. The new lease expires on February&amp;#xA0;28, 2023 and can be
 extended for an additional term of 5 years.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In January 2016, the Company entered into an operating lease
 agreement to lease office space near San Francisco, California. The
 operating lease agreement expires on April&amp;#xA0;30, 2019. In
 September 2017, the Company entered into a sublease agreement to
 sublet the premises to a third party until April&amp;#xA0;30, 2019. The
 fair value of the remaining contractual obligation, net of sublease
 income, was included in accrued liabilities in the accompanying
 condensed consolidated balance sheet as of March&amp;#xA0;31, 2018.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In addition to base rent, these leases require payment of taxes and
 other operating costs. These operating costs are not included in
 the table below.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 As of March&amp;#xA0;31, 2018, the aggregate future &lt;font style="white-space:nowrap"&gt;non-cancelable&lt;/font&gt; minimum lease payments
 associated with these operating leases are as follows:&lt;/p&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table cellspacing="0" cellpadding="0" width="68%" border="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" align="center"&gt;
 &lt;tr&gt;
 &lt;td width="81%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="14%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:96.20pt; display:inline; font-size:8pt; font-family:Times New Roman;"&gt;
 &lt;b&gt;Years Ending December&amp;#xA0;31:&lt;/b&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;
 &lt;b&gt;Operating&amp;#xA0;Leases&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center"&gt;
 &lt;b&gt;(in&amp;#xA0;thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Remainder of 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;307&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2019&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;266&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2020&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;220&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2021&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;223&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2022&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;178&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Thereafter&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:3.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Total &lt;sup style="font-size:85%; vertical-align:top"&gt;(a)&lt;/sup&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,194&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;(a)&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;Minimum lease payments have not been
 reduced by minimum sublease rentals of $0.1&amp;#xA0;million due in the
 future under sublease.&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The total rent expense was $0.1&amp;#xA0;million for the three months
 ended March&amp;#xA0;31, 2018 and 2017.&lt;/p&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Legal&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 On November&amp;#xA0;9, 2016, a purported securities class action
 lawsuit was filed in the United States District Court for the
 Southern District of New York against the Company and certain of
 its executive officers (the New York Lawsuit). The New York Lawsuit
 was brought by purported stockholders of the Company seeking to
 represent a class consisting of stockholders who purchased stock
 between July&amp;#xA0;15, 2015 and June&amp;#xA0;6, 2016. The New York
 Lawsuit asserts claims under Sections&amp;#xA0;10(b) and 20(a) of the
 Exchange Act and seeks unspecified damages and other relief. On
 March&amp;#xA0;13, 2018, the United States District Court for the
 Southern District of New York granted the defendants&amp;#x2019; motion
 to dismiss and entered a final judgment dismissing the New York
 Lawsuit with prejudice. Plaintiffs have filed a notice of appeal.
 The Company believes that the claims in the New York Lawsuit are
 without merit and intends to defend the lawsuit vigorously. It is
 possible that additional similar lawsuits could be filed. Due to
 the early stage of the litigation, the Company is unable to predict
 the outcome of this matter and is unable to make a meaningful
 estimate of the amount or range of loss, if any, that could result
 from an unfavorable outcome.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 On November&amp;#xA0;18, 2016, a purported securities class action
 lawsuit was filed in the Superior Court of the State of California
 for the County of San Mateo against the Company, certain of its
 executive officers and directors, and the underwriters for the
 Company&amp;#x2019;s initial public offering of its common stock. On
 February&amp;#xA0;9, 2017, a substantially identical putative class
 action suit was filed in the Superior Court of the State of
 California for the County of San Mateo asserting the same claims on
 behalf of the same putative class (the two lawsuits together, the
 California Lawsuits). The California Lawsuits were brought by
 purported stockholders of the Company seeking to represent a class
 consisting of stockholders who purchased stock pursuant to and/or
 traceable to the Company&amp;#x2019;s Registration Statement on Form
 &lt;font style="white-space:nowrap"&gt;S-1.&lt;/font&gt; The lawsuits assert
 claims under Sections&amp;#xA0;11 and 15 of the Exchange Act and seek
 unspecified damages and other relief. The California Lawsuits
 remain pending. The Company believes that the claims are without
 merit and intends to defend the California Lawsuits vigorously. It
 is possible that additional similar lawsuits could be filed. Due to
 the early stage of the litigation, the Company is unable to predict
 the outcome of these cases and is unable to make a meaningful
 estimate of the amount or range of loss, if any, that could result
 from an unfavorable outcome.&lt;/p&gt;
 &lt;p style="font-size:1px;margin-top:12px;margin-bottom:0px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 From time to time, the Company may become subject to other legal
 proceedings, claims and litigation arising in the ordinary course
 of business. In addition, the Company may receive letters alleging
 infringement of patent or other intellectual property rights. The
 Company is not currently a party to any other material legal
 proceedings, nor is it aware of any pending or threatened
 litigation that, in the Company&amp;#x2019;s opinion, would have a
 material adverse effect on the business, operating results, cash
 flows or financial condition should such litigation be resolved
 unfavorably.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:CommitmentsAndContingenciesDisclosureTextBlock>
  <us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_19" unitRef="iso4217_USD">33468000</us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect>
  <us-gaap:ComprehensiveIncomePolicyPolicyTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_3E4941E7-F37E-43AD-B9EF-67F5BF9678CA_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Comprehensive Loss&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company had no components of comprehensive loss other than net
 loss for all periods presented.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:ComprehensiveIncomePolicyPolicyTextBlock>
  <dei:CurrentFiscalYearEndDate contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8CE924CE-1C99-4F12-B286-90DAADA61E8B_1_3">--12-31</dei:CurrentFiscalYearEndDate>
  <us-gaap:DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_95982B3A-064B-4D29-A3DC-5D96295C976A_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Prepaid Expenses and Other Current Assets&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Prepaid expenses and other current assets consist of the
 following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="76%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Prepaid research and development project costs&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,242&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;549&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Prepaid insurance&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;276&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;478&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Other receivables&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;328&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;103&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Other&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;313&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;247&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total prepaid expenses and other current assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,159&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,377&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock>
  <us-gaap:DepreciationDepletionAndAmortization contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_4" unitRef="iso4217_USD">29000</us-gaap:DepreciationDepletionAndAmortization>
  <us-gaap:EarningsPerShareBasicAndDiluted contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="2" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_9" unitRef="iso4217_USD_per_shares">-0.19</us-gaap:EarningsPerShareBasicAndDiluted>
  <us-gaap:EarningsPerShareTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_E58EDE87-2656-41FE-B271-6A345D270BC9_1_0">&lt;div&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;&lt;b&gt;3.&lt;/b&gt;&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;&lt;b&gt;Net Loss Per Share&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Basic net loss per share is calculated by dividing net loss by the
 weighted-average number of common shares outstanding during the
 period without consideration for common stock equivalents. Diluted
 net loss per share is computed by dividing net loss by the
 weighted-average number of common share equivalents outstanding for
 the period determined using the treasury-stock method. For purposes
 of this calculation, stock options are considered to be common
 stock equivalents and are only included in the calculation of
 diluted net loss per share when their effect is dilutive. As of
 March&amp;#xA0;31, 2018 and March&amp;#xA0;31, 2017, 10,202,831 and
 7,615,052 outstanding options to purchase common stock,
 respectively, were excluded from the calculation of diluted net
 loss per share for the periods presented because including them
 would have been antidilutive.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:EarningsPerShareTextBlock>
  <us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_343060C1-35E4-4473-9EE7-ED9A48A1DC36_1_0">&lt;div&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="100%" border="0"&gt;
 &lt;tr style="PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top" width="4%" align="left"&gt;&lt;b&gt;8.&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="top" align="left"&gt;&lt;b&gt;Stock-Based Compensation&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 In the accompanying condensed consolidated statements of
 operations, the Company recognized stock-based compensation expense
 for its employees and &lt;font style="WHITE-SPACE: nowrap"&gt;non-employees&lt;/font&gt; as follows:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="82%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;Three&amp;#xA0;Months&amp;#xA0;Ended&lt;br /&gt;
 March&amp;#xA0;31,&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Research and development&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;998&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,013&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 General and administrative&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;501&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;514&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total stock-based compensation&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,499&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,527&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Determination of Fair Value&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The estimated grant-date fair values of all of the Company&amp;#x2019;s
 stock-based awards were calculated using the Black-Scholes option
 pricing model, based on assumptions as follows:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="74%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="3" align="center"&gt;&lt;b&gt;Three&amp;#xA0;Months&amp;#xA0;Ended&lt;br /&gt;
 March&amp;#xA0;31,&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" align="center"&gt;&lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" align="center"&gt;&lt;b&gt;2017&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Expected term (in years)&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;5.4&amp;#xA0;&amp;#x2013;&amp;#xA0;6.9&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;5.4&amp;#xA0;&amp;#x2013;7.0&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Expected volatility&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;88&amp;#xA0;&amp;#x2013;&amp;#xA0;91%&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;89&amp;#xA0;&amp;#x2013;&amp;#xA0;96%&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Risk-free interest rate&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;2.7&amp;#xA0;&amp;#x2013;&amp;#xA0;2.8%&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;2.0&amp;#xA0;&amp;#x2013;&amp;#xA0;2.3%&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Expected dividend rate&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;&amp;#x2014;%&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;&amp;#x2014;%&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Equity Incentive Plans&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;2015 Plan&lt;/i&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The 2015 Equity Incentive Plan (2015 Plan) became effective on
 July&amp;#xA0;14, 2015. As of March&amp;#xA0;31, 2018, 8,621,853 shares
 were reserved for issuance under the 2015 Plan. The number of
 shares reserved for issuance under the 2015 Plan will increase
 automatically on January&amp;#xA0;1 of each calendar year 2016 through
 2025 by the number of shares equal to 4% of the total outstanding
 shares of the Company&amp;#x2019;s common stock as of the immediately
 preceding December&amp;#xA0;31. The Company&amp;#x2019;s Board of Directors
 or Compensation Committee may reduce the amount of the increase in
 any particular year. The exercise price of each stock-based award
 issued under the 2015 Plan is required to be no less than the fair
 value of the Company&amp;#x2019;s capital stock. The vesting and
 exercise provisions of options or restricted awards granted are
 determined individually with each grant. Stock options have a
 &lt;font style="WHITE-SPACE: nowrap"&gt;10-year&lt;/font&gt; life and expire if
 not exercised within that period or if not exercised within three
 months of cessation of employment with the Company or such longer
 period of time as specified in the option agreement.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0px; FONT-SIZE: 1px; MARGIN-TOP: 18px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 0pt"&gt;
 &lt;i&gt;2008 Plan&lt;/i&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company granted options under the 2008 Stock Plan (2008 Plan)
 until July 2015 when it was terminated as to future awards,
 although it continues to govern the terms of options that remain
 outstanding under the 2008 Plan. The 2008 Plan provided for the
 granting of Incentive Stock Options (ISO), nonqualified stock
 options and stock purchase rights. In connection with the Board of
 Director&amp;#x2019;s approval of the 2015 Plan, all remaining shares
 available for future award under the 2008 Plan were transferred to
 the 2015 Plan, and the 2008 Plan was terminated.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 A summary of activity under the 2008 Plan and 2015 Plan and related
 information is as follows:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="100%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="58%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;Options Outstanding&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Shares&lt;br /&gt;
 Available&lt;br /&gt;
 for Grant&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Number&lt;br /&gt;
 of Shares&lt;br /&gt;
 Outstanding&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Weighted-&lt;br /&gt;
 Average&lt;br /&gt;
 Exercise&lt;br /&gt;
 Price Per&lt;br /&gt;
 Share&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Weighted-&lt;br /&gt;
 Average&lt;br /&gt;
 Remaining&lt;br /&gt;
 Contractual&lt;br /&gt;
 Term&lt;br /&gt;
 (Years)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Aggregate&lt;br /&gt;
 Intrinsic&lt;br /&gt;
 Value of&lt;br /&gt;
 Outstanding&lt;br /&gt;
 Options&lt;br /&gt;
 (in&amp;#xA0;thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Outstanding &amp;#x2014; December&amp;#xA0;31, 2017&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,503,770&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;7,470,601&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3.09&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;8.12&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;12,363&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Awards authorized&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,095,808&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Options granted&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(2,854,350&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,854,350&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2.36&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Options exercised&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(64,458&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1.57&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Options forfeited/cancelled&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;57,662&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(57,662&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;5.65&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Outstanding &amp;#x2014; March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;802,890&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;10,202,831&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2.88&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;8.45&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3,050&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Exercisable &amp;#x2014; March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;4,582,347&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3.00&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;7.54&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,198&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Vested and expected to vest &amp;#x2014; March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;10,202,831&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2.88&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;8.45&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3,050&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The weighted-average grant date fair values of options granted
 during the three months ended March&amp;#xA0;31, 2018 and 2017 was
 $1.76 and $1.12 per share, respectively. The aggregate intrinsic
 value of options exercised was $0.1&amp;#xA0;million for the three
 months ended March&amp;#xA0;31, 2018 and 2017. The total grant date
 fair value of options vested for the three months ended
 March&amp;#xA0;31, 2018 and 2017 was $1.7&amp;#xA0;million and
 $2.2&amp;#xA0;million, respectively.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 As of March&amp;#xA0;31, 2018, total unrecognized stock-based
 compensation related to unvested stock options was
 $12.6&amp;#xA0;million. These costs are expected to be recognized over
 a remaining weighted-average period of 2.4 years as of
 March&amp;#xA0;31, 2018.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;2015 Employee Stock Purchase Plan&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company adopted the 2015 Employee Stock Purchase Plan (ESPP)
 and initially reserved 700,000 shares of common stock as of its
 effective date of July&amp;#xA0;15, 2015. The number of shares
 initially reserved for issuance under the ESPP will increase
 automatically on January&amp;#xA0;1 for nine years from the first
 offering date by the number of shares equal to 1% of the total
 outstanding shares of the Company&amp;#x2019;s common stock as of the
 immediately preceding December 31. The aggregate number of shares
 issued over the term of the 2015 Employee Stock Purchase Plan will
 not exceed 3,400,000 shares of common stock.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 Under the ESPP, participants are offered the option to purchase
 shares of the Company&amp;#x2019;s common stock at a 15% discount during
 a series of discrete offering periods, subject to any plan
 limitations. The ESPP will not become effective until such time as
 the Compensation Committee determines in the future, and as of
 March&amp;#xA0;31, 2018, the initial offering periods had not
 commenced. As of March&amp;#xA0;31, 2018, no shares of common stock
 have been issued to employees participating in the ESPP and 700,000
 shares were available for issuance under the ESPP.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock>
  <dei:DocumentFiscalPeriodFocus contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_581D87E6-470F-4A5A-A241-C0C611FACBD3_1_4">Q1</dei:DocumentFiscalPeriodFocus>
  <dei:DocumentFiscalYearFocus contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_581D87E6-470F-4A5A-A241-C0C611FACBD3_1_3">2018</dei:DocumentFiscalYearFocus>
  <dei:DocumentType contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_581D87E6-470F-4A5A-A241-C0C611FACBD3_1_0">10-Q</dei:DocumentType>
  <us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="2" id="id_12173116_FE8E581E-8675-4231-89F8-097950A24985_1_0" unitRef="pure">0.21</us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate>
  <dei:DocumentPeriodEndDate contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_581D87E6-470F-4A5A-A241-C0C611FACBD3_1_2">2018-03-31</dei:DocumentPeriodEndDate>
  <us-gaap:EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_18" unitRef="iso4217_USD">-20000</us-gaap:EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents>
  <us-gaap:FairValueAssetsMeasuredOnRecurringBasisTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8F81B9C4-1BDA-499C-A0ED-3A9A2A9BCFA2_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The following table sets forth the fair value of the
 Company&amp;#x2019;s financial assets measured on a recurring basis by
 level within the fair value hierarchy:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="92%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="70%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;March&amp;#xA0;31, 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;1&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;2&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;3&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Total&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 &lt;b&gt;Financial Assets&lt;/b&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom" colspan="13"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Restricted money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;175&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;175&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total financial assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,623&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,623&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="92%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="72%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;December&amp;#xA0;31, 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;1&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;2&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;3&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Total&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 &lt;b&gt;Financial Assets&lt;/b&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom" colspan="13"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,792&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,792&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Restricted money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;187&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;187&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total financial assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,979&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,979&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:FairValueAssetsMeasuredOnRecurringBasisTextBlock>
  <dei:EntityRegistrantName contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8CE924CE-1C99-4F12-B286-90DAADA61E8B_1_1">Sierra Oncology, Inc.</dei:EntityRegistrantName>
  <us-gaap:FairValueDisclosuresTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_F0E603EB-0B12-4D31-B297-9055DA55C1CC_1_0">&lt;div&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="100%" border="0"&gt;
 &lt;tr style="PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top" width="4%" align="left"&gt;&lt;b&gt;4.&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="top" align="left"&gt;&lt;b&gt;Fair Value Measurements&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company measures and reports its cash equivalents and
 restricted cash at fair value. The following table sets forth the
 fair value of the Company&amp;#x2019;s financial assets measured on a
 recurring basis by level within the fair value hierarchy:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="92%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="70%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;March&amp;#xA0;31, 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;1&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;2&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;3&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Total&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 &lt;b&gt;Financial Assets&lt;/b&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom" colspan="13"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Restricted money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;175&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;175&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total financial assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,623&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,623&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="92%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="72%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;December&amp;#xA0;31, 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;1&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;2&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Level&amp;#xA0;3&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Total&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 &lt;b&gt;Financial Assets&lt;/b&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom" colspan="13"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,792&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,792&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Restricted money market funds&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;187&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;187&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total financial assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,979&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,979&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0px; FONT-SIZE: 1px; MARGIN-TOP: 12px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 0pt"&gt;
 Money market funds and restricted money market funds are measured
 at fair value on a recurring basis using quoted prices and are
 classified as a Level&amp;#xA0;1 input.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 There were no transfers between Levels 1, 2 or 3 during the three
 months ended March&amp;#xA0;31, 2018.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:FairValueDisclosuresTextBlock>
  <dei:EntityCentralIndexKey contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8CE924CE-1C99-4F12-B286-90DAADA61E8B_1_2">0001290149</dei:EntityCentralIndexKey>
  <us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3 contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="INF" id="id_12173116_1AF520AF-2B38-4915-B7F4-88957BE7923E_1_6" unitRef="iso4217_USD">0</us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3>
  <us-gaap:FairValueOfFinancialInstrumentsPolicy contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8D0F3407-7C2F-47FE-ADD6-662A6769079C_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Fair Value of Financial Instruments&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company&amp;#x2019;s cash and cash equivalents, restricted cash,
 other current assets, accounts payable, and accrued liabilities
 approximate their fair value at March&amp;#xA0;31, 2018 and
 December&amp;#xA0;31, 2017, due to their short duration.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The Company utilizes valuation techniques that maximize the use of
 observable inputs and minimize the use of unobservable inputs to
 the extent possible. The Company determines the fair value of its
 financial instruments based on assumptions that market participants
 would use in pricing an asset or liability in the principal or most
 advantageous market. When considering market participant
 assumptions in fair value measurements, the following fair value
 hierarchy distinguishes between observable and unobservable inputs,
 which are categorized in one of the following levels:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 4%; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;Level&lt;/i&gt;&lt;i&gt;&amp;#xA0;1&lt;/i&gt; &amp;#x2013; Inputs are unadjusted quoted
 prices in active markets for identical assets or liabilities at the
 measurement date;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 4%; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;Level&lt;/i&gt;&lt;i&gt;&amp;#xA0;2&lt;/i&gt; &amp;#x2013; Inputs are observable,
 unadjusted quoted prices in active markets for similar assets or
 liabilities, unadjusted quoted prices for identical or similar
 assets or liabilities in markets that are not active, or other
 inputs that are observable or can be corroborated by observable
 market data for substantially the full term of the related assets
 or liabilities; and&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 4%; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;Level&lt;/i&gt;&lt;i&gt;&amp;#xA0;3&lt;/i&gt; &amp;#x2013; Unobservable inputs that are
 significant to the measurement of the fair value of the assets or
 liabilities that are supported by little or no market data.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:FairValueOfFinancialInstrumentsPolicy>
  <dei:EntityFilerCategory contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8CE924CE-1C99-4F12-B286-90DAADA61E8B_1_4">Smaller Reporting Company</dei:EntityFilerCategory>
  <us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3 contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="INF" id="id_12173116_1AF520AF-2B38-4915-B7F4-88957BE7923E_1_7" unitRef="iso4217_USD">0</us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3>
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 &lt;p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Foreign Currency&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The functional currency of the Company&amp;#x2019;s foreign subsidiaries
 is the U.S.&amp;#xA0;Dollar. Transactions denominated in currencies
 other than the functional currency are recorded at prevailing
 exchange rates during the period. At the end of each reporting
 period, monetary assets and liabilities are remeasured to the
 functional currency using exchange rates in effect at the balance
 sheet date. &lt;font style="white-space:nowrap"&gt;Non-monetary&lt;/font&gt;
 assets and liabilities are recorded at historical exchange rates.
 Gains and losses related to remeasurement are recorded in other
 income in the condensed consolidated statements of operations. The
 net foreign exchange transaction gains (losses) included in other
 income in the accompanying condensed consolidated statements of
 operations was insignificant for the three months ended
 March&amp;#xA0;31, 2018 and 2017.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock>
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 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;&lt;b&gt;9.&lt;/b&gt;&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;&lt;b&gt;Income Taxes&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company did not record a provision for U.S. federal income
 taxes for the three months ended March&amp;#xA0;31, 2018 because it
 expects to generate a loss for the year ended December&amp;#xA0;31,
 2018. The income tax expense of $43,000 and $34,000 for the three
 months ended March&amp;#xA0;31, 2018 and 2017, respectively,
 represented foreign taxes. The Company&amp;#x2019;s net U.S. deferred
 tax assets continue to be offset by a full valuation allowance.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 On December&amp;#xA0;22, 2017, the U.S. government enacted
 comprehensive tax legislation commonly referred to as the Tax Cuts
 and Jobs Act (Tax Act). The Tax Act significantly revises U.S. tax
 law by, among other provisions, lowering the U.S. federal statutory
 income tax rate from 35% to 21%, changing rules related to uses and
 limitations of net operating loss carryforwards created in tax
 years beginning after December&amp;#xA0;31, 2017 and eliminating or
 reducing certain income tax deductions.&lt;/p&gt;
 &lt;p style="font-size:1px;margin-top:12px;margin-bottom:0px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The effects of changes in tax laws are required to be recognized in
 the period in which the legislation is enacted. However, due to the
 complexity and significance of the Tax Act&amp;#x2019;s provisions, the
 FASB issued ASU &lt;font style="white-space:nowrap"&gt;No.&amp;#xA0;2018-06,&lt;/font&gt; &lt;i&gt;Income Taxes
 (Topic 740)&lt;/i&gt; pursuant to the SEC staff issued Staff Accounting
 Bulletin No.&amp;#xA0;118 (SAB 118), which allows companies to record
 the tax effects of the Tax Act on a provisional basis based on a
 reasonable estimate, and then, if necessary, subsequently adjust
 such amounts during a limited measurement period as more
 information becomes available. The measurement period ends when a
 company has obtained, prepared, and analyzed the information
 necessary to finalize its accounting, but cannot extend beyond one
 year from enactment.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In connection with the Company&amp;#x2019;s initial analysis of the Tax
 Act, it recorded a decrease of its net deferred tax assets of
 $7.2&amp;#xA0;million for the period ended December&amp;#xA0;31, 2017, to
 account for the rate reduction. This did not have an impact on the
 Company&amp;#x2019;s financial statements since its U.S. deferred tax
 assets are fully offset by a valuation allowance. However, given
 the significant complexity of the Tax Act, these estimates may be
 adjusted during the measurement period.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:IncomeTaxDisclosureTextBlock>
  <us-gaap:IncomeTaxesPaidNet contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_23" unitRef="iso4217_USD">73000</us-gaap:IncomeTaxesPaidNet>
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 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Income Taxes&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company uses the asset and liability method of accounting for
 income taxes. Under this method, deferred tax assets and
 liabilities are determined based on the differences between the
 financial reporting and the tax bases of assets and liabilities and
 are measured using the enacted tax rates and laws that will be in
 effect when the differences are expected to reverse. Management
 makes an assessment of the likelihood that the resulting deferred
 tax assets will be realized. A valuation allowance is provided when
 it is more likely than not that some portion or all of a deferred
 tax asset will not be realized. Due to the Company&amp;#x2019;s
 historical operating performance and the recorded cumulative net
 losses in prior fiscal periods, the net U.S. deferred tax assets
 have been offset by a full valuation allowance.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company recognizes uncertain income tax positions at the
 largest amount that is more likely than not to be sustained upon
 audit by the relevant taxing authority. An uncertain income tax
 position will not be recognized if it has less than a 50%
 likelihood of being sustained. Changes in recognition or
 measurement are reflected in the period in which judgment occurs.
 The Company recognizes interest and penalties related to the
 underpayment of income taxes as a component of provision for income
 taxes.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:IncomeTaxPolicyTextBlock>
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  <us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_10" unitRef="iso4217_USD">-12609000</us-gaap:NetCashProvidedByUsedInOperatingActivitiesContinuingOperations>
  <us-gaap:OperatingExpenses contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_3" unitRef="iso4217_USD">11754000</us-gaap:OperatingExpenses>
  <us-gaap:NetCashProvidedByUsedInFinancingActivitiesContinuingOperations contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_17" unitRef="iso4217_USD">46097000</us-gaap:NetCashProvidedByUsedInFinancingActivitiesContinuingOperations>
  <us-gaap:NetIncomeLoss contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_8" unitRef="iso4217_USD">-11525000</us-gaap:NetIncomeLoss>
  <us-gaap:NumberOfOperatingSegments contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="INF" id="id_12173116_D079D16D-B88F-48D5-A0B0-2766DEDE47ED_1_0" unitRef="Segment">1</us-gaap:NumberOfOperatingSegments>
  <us-gaap:OperatingIncomeLoss contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_4" unitRef="iso4217_USD">-11754000</us-gaap:OperatingIncomeLoss>
  <us-gaap:NewAccountingPronouncementsPolicyPolicyTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_0A9B2827-A7B7-40FA-8EC1-FC694D0CD551_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Recent Accounting Pronouncements Not Yet Effective&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In February 2016, the Financial Accounting Standards Board (FASB)
 issued FASB Accounting Standards Update (ASU) &lt;font style="white-space:nowrap"&gt;No.&amp;#xA0;2016-02,&lt;/font&gt; &lt;i&gt;Leases (Topic
 842)&lt;/i&gt;. The amendments in this update require that organizations
 recognize lease assets and lease liabilities on the balance sheet
 and disclose key information about leasing arrangements. This ASU
 is effective for financial statements issued for fiscal years
 beginning after December&amp;#xA0;15, 2018, and interim periods within
 those fiscal years, with early adoption permitted. The Company will
 adopt the new standard effective January&amp;#xA0;1, 2019 and expects
 its operating leases, as disclosed in Note 6 &amp;#x201C;Commitments and
 Contingencies&amp;#x201D;, to be subject to the new standard. The
 Company will &lt;font style="white-space:nowrap"&gt;&lt;font style="white-space:nowrap"&gt;recognize&amp;#xA0;right-of-use&amp;#xA0;assets&lt;/font&gt;&lt;/font&gt;
 and operating lease liabilities on its consolidated balance sheets
 upon adoption, which will increase its total assets and
 liabilities.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:NewAccountingPronouncementsPolicyPolicyTextBlock>
  <us-gaap:OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_F1FE371E-BB2D-467B-84DA-025E78124ADB_1_0">&lt;div&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;&lt;b&gt;1.&lt;/b&gt;&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;&lt;b&gt;The Company and Basis of
 Presentation&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Organization and Description of Business&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Sierra Oncology,&amp;#xA0;Inc. (together with its subsidiaries,
 collectively referred to as the &amp;#x201C;Company&amp;#x201D;), a Delaware
 corporation, is a clinical stage drug development company advancing
 targeted therapeutics for the treatment of patients with cancer.
 Sierra Oncology&amp;#x2019;s lead drug candidate is SRA737, a potent,
 highly selective, orally bioavailable small molecule inhibitor of
 Checkpoint kinase 1 (Chk1), a key regulator of cell cycle
 progression and the DNA Damage Response (DDR) replication stress
 response. Sierra Oncology is also advancing SRA141, a potent,
 selective and orally bioavailable small molecule inhibitor of cell
 division cycle 7 kinase (Cdc7) undergoing preclinical
 development.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company&amp;#x2019;s primary activities since inception have been
 conducting research and development activities, conducting
 preclinical and clinical testing, recruiting personnel, performing
 business and financial planning, identifying and evaluating
 additional drug candidates for potential &lt;font style="white-space:nowrap"&gt;in-licensing&lt;/font&gt; or acquisition, and
 raising capital to support development activities.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company has not generated any product revenue related to its
 primary business purpose to date, nor has it generated any income,
 and is subject to a number of risks and uncertainties, which
 include dependence on key individuals, the need to identify and
 successfully develop commercially viable products, the need to
 obtain regulatory approval for its products and commercialize them,
 and the need to obtain adequate additional financing to fund the
 development of its product candidates.&lt;/p&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;&lt;font style="white-space:nowrap"&gt;Follow-On&lt;/font&gt;
 Offering&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 On March&amp;#xA0;6, 2018, the Company completed an underwritten public
 offering of an aggregate of 21,850,000 shares of common stock,
 including the underwriters&amp;#x2019; exercise of their overallotment
 option, at a price to the public of $2.25 per share. The aggregate
 net proceeds received by the Company from the offering were
 $46.0&amp;#xA0;million, net of underwriting discounts and commissions
 and offering expenses of $3.2&amp;#xA0;million.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock>
  <us-gaap:OtherNoncashIncomeExpense contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_5" unitRef="iso4217_USD">-41000</us-gaap:OtherNoncashIncomeExpense>
  <us-gaap:OtherNonoperatingIncomeExpense contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_5" unitRef="iso4217_USD">272000</us-gaap:OtherNonoperatingIncomeExpense>
  <us-gaap:ProceedsFromIssuanceOfCommonStock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_15" unitRef="iso4217_USD">45996000</us-gaap:ProceedsFromIssuanceOfCommonStock>
  <us-gaap:PropertyPlantAndEquipmentTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_FACB0E19-8B23-44FC-8713-F95BB4ADC826_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Property and equipment, net consists of the following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="76%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="9%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="9%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Software&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;273&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;254&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Computer equipment&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;93&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;93&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Leasehold improvements&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;79&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;79&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Furniture and fixtures&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Property and equipment, gross&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;429&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Less: accumulated depreciation&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(304&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(275&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total property and equipment, net&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;144&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;154&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:PropertyPlantAndEquipmentTextBlock>
  <us-gaap:ProceedsFromStockOptionsExercised contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_16" unitRef="iso4217_USD">101000</us-gaap:ProceedsFromStockOptionsExercised>
  <us-gaap:PropertyPlantAndEquipmentPolicyTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_4DE8A28E-927F-4A3C-8580-2AB0C007FDA8_1_0">&lt;div&gt;
 &lt;p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Property and Equipment, Net&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Property and equipment, net are stated at cost, less accumulated
 depreciation. Depreciation on property and equipment, excluding
 leasehold improvements, is computed using the straight-line method
 over the estimated useful lives of the respective assets, generally
 three to five years. Depreciation begins at the time the asset is
 placed in service. Maintenance and repairs are charged to
 operations as incurred. Upon sale or retirement of assets, the cost
 and related accumulated depreciation are removed from the condensed
 consolidated balance sheet and the resulting gain or loss is
 reflected in the condensed consolidated statement of operations.
 Leasehold improvements are amortized on a straight-line basis over
 the shorter of the estimated useful lives of the assets or the
 remaining lease term.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:PropertyPlantAndEquipmentPolicyTextBlock>
  <us-gaap:ResearchAndDevelopmentExpense contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_1" unitRef="iso4217_USD">8334000</us-gaap:ResearchAndDevelopmentExpense>
  <us-gaap:ResearchAndDevelopmentExpensePolicy contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_FBA735BD-8DFD-4E8F-AFF5-7EABE3BABE1F_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Research and Development Costs&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Research and development costs are expensed as incurred. The
 Company accounts for &lt;font style="white-space:nowrap"&gt;non-refundable&lt;/font&gt; advance payments for
 goods and services that will be used in future research and
 development activities as expenses when the goods have been
 received or when the service has been performed rather than when
 the payment is made. Depending on the timing of payments to service
 providers of research and development costs, the Company recognizes
 prepaid expenses or accrued expenses related to these costs. These
 prepaid or accrued expenses are based on management&amp;#x2019;s
 estimates of the work performed under service agreements and
 milestones achieved. In the event that a clinical trial is
 terminated early, the Company records an accrual for the estimated
 remaining costs to complete the trial in the period of
 termination.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Upfront payments made in connection with license agreements are
 expensed as research and developments costs, as the assets acquired
 do not have alterative future use. Contingent milestone payment
 obligations due to third parties under license agreements are
 expensed when the milestones are considered probable of
 occurring.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Research and development costs include fees incurred in connection
 with license agreements, compensation and other related costs for
 employees engaged in&amp;#xA0;research and development, costs
 associated with research and preclinical studies, clinical trials,
 regulatory activities, manufacturing activities to support clinical
 activities, fees paid to external service providers that conduct
 certain research and development, clinical, and manufacturing
 activities on behalf of the Company and an allocation of overhead
 expenses.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:ResearchAndDevelopmentExpensePolicy>
  <us-gaap:RestructuringAndRelatedActivitiesDisclosureTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_ADB71F47-6CE6-4B86-80C7-0B107094169F_1_0">&lt;div&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;&lt;b&gt;10.&lt;/b&gt;&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;&lt;b&gt;Restructuring Costs&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 In June 2016, the Company halted investment in PNT2258 and closed
 the related Phase 2 clinical trials to further enrollment. As a
 result, the Company closed its research facility in Plymouth,
 Michigan, renegotiated and terminated certain contracts, and
 implemented staff reductions in the United States and Canada.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The following table summarizes restructuring activities for the
 three months ended March&amp;#xA0;31, 2018:&lt;/p&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table cellspacing="0" cellpadding="0" width="68%" border="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" align="center"&gt;
 &lt;tr&gt;
 &lt;td width="84%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="13%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;&lt;b&gt;Contract&lt;br /&gt;
 Termination&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center"&gt;
 &lt;b&gt;(in&amp;#xA0;thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Accrual balance at December&amp;#xA0;31, 2017&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;137&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Cash payments&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(38&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:3.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Accrual balance at March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The accrual balance is currently expected to be substantially paid
 by the end of 2018.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:RestructuringAndRelatedActivitiesDisclosureTextBlock>
  <us-gaap:ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_C1EBA25C-E178-4927-B372-B193AC98E14F_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 In the accompanying condensed consolidated statements of
 operations, the Company recognized stock-based compensation expense
 for its employees and &lt;font style="WHITE-SPACE: nowrap"&gt;non-employees&lt;/font&gt; as follows:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="82%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;Three&amp;#xA0;Months&amp;#xA0;Ended&lt;br /&gt;
 March&amp;#xA0;31,&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Research and development&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;998&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,013&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 General and administrative&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;501&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;514&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total stock-based compensation&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,499&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,527&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock>
  <us-gaap:ScheduleOfAccruedLiabilitiesTableTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_E615FD6D-C7C2-4CEF-BAEA-4EB66467C9BE_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Accrued liabilities consist of the following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="76%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued research and development costs&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,994&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,763&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued employee-related costs&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;862&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,699&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued professional fees&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;753&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;317&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued restructuring costs (Note 10)&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;137&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Other&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;190&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;217&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total accrued liabilities&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;4,898&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;6,133&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfAccruedLiabilitiesTableTextBlock>
  <us-gaap:ScheduleOfCashAndCashEquivalentsTableTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_A7A21D78-12A4-4011-936E-8B2E3FA86066_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Cash and cash equivalents consist of the following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="74%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="6%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="6%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;/b&gt;&lt;br /&gt;
 &lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Cash&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;381&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;556&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Cash equivalents:&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Money market accounts&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,792&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total cash and cash equivalents&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,829&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;100,348&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfCashAndCashEquivalentsTableTextBlock>
  <us-gaap:ScheduleOfShareBasedCompensationActivityTableTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_F2D9AF38-5E58-4ECC-80F0-A0A4F695FE4D_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 A summary of activity under the 2008 Plan and 2015 Plan and related
 information is as follows:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="100%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="58%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="14" align="center"&gt;&lt;b&gt;Options Outstanding&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Shares&lt;br /&gt;
 Available&lt;br /&gt;
 for Grant&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Number&lt;br /&gt;
 of Shares&lt;br /&gt;
 Outstanding&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Weighted-&lt;br /&gt;
 Average&lt;br /&gt;
 Exercise&lt;br /&gt;
 Price Per&lt;br /&gt;
 Share&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Weighted-&lt;br /&gt;
 Average&lt;br /&gt;
 Remaining&lt;br /&gt;
 Contractual&lt;br /&gt;
 Term&lt;br /&gt;
 (Years)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;Aggregate&lt;br /&gt;
 Intrinsic&lt;br /&gt;
 Value of&lt;br /&gt;
 Outstanding&lt;br /&gt;
 Options&lt;br /&gt;
 (in&amp;#xA0;thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Outstanding &amp;#x2014; December&amp;#xA0;31, 2017&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,503,770&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;7,470,601&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3.09&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;8.12&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;12,363&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Awards authorized&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,095,808&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Options granted&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(2,854,350&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,854,350&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2.36&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Options exercised&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(64,458&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1.57&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Options forfeited/cancelled&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;57,662&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(57,662&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;5.65&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Outstanding &amp;#x2014; March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;802,890&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;10,202,831&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2.88&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;8.45&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3,050&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Exercisable &amp;#x2014; March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;4,582,347&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3.00&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;7.54&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,198&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Vested and expected to vest &amp;#x2014; March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;10,202,831&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2.88&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;8.45&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3,050&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfShareBasedCompensationActivityTableTextBlock>
  <us-gaap:ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_5AE7DF96-0184-49F8-9805-4D4365FED6A9_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The estimated grant-date fair values of all of the Company&amp;#x2019;s
 stock-based awards were calculated using the Black-Scholes option
 pricing model, based on assumptions as follows:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="74%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="3%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="3" align="center"&gt;&lt;b&gt;Three&amp;#xA0;Months&amp;#xA0;Ended&lt;br /&gt;
 March&amp;#xA0;31,&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" align="center"&gt;&lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" align="center"&gt;&lt;b&gt;2017&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Expected term (in years)&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;5.4&amp;#xA0;&amp;#x2013;&amp;#xA0;6.9&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;5.4&amp;#xA0;&amp;#x2013;7.0&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Expected volatility&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;88&amp;#xA0;&amp;#x2013;&amp;#xA0;91%&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;89&amp;#xA0;&amp;#x2013;&amp;#xA0;96%&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Risk-free interest rate&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;2.7&amp;#xA0;&amp;#x2013;&amp;#xA0;2.8%&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;2.0&amp;#xA0;&amp;#x2013;&amp;#xA0;2.3%&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Expected dividend rate&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;&amp;#x2014;%&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="center"&gt;&amp;#x2014;%&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock>
  <us-gaap:ScheduleOfStockByClassTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_218B046E-FF2C-4C8F-BECC-A12750891E92_1_0">&lt;div&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company is required to reserve and keep available out of its
 authorized but unissued shares of common stock a number of shares
 sufficient to effect the conversion of all outstanding options
 granted and available for grant under the incentive plans and
 shares reserved for issuance under the employee stock purchase
 plan.&lt;/p&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table cellspacing="0" cellpadding="0" width="76%" border="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" align="center"&gt;
 &lt;tr&gt;
 &lt;td width="73%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Outstanding stock options&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;10,202,831&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;7,470,601&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Shares reserved for future option grants&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;802,890&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,503,770&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Shares reserved under the 2015 employee stock purchase plan&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;700,000&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;700,000&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:3.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Total common stock reserved for issuance&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;11,705,721&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;9,674,371&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfStockByClassTextBlock>
  <us-gaap:SegmentReportingPolicyPolicyTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_E3A131B1-91D8-45E5-8347-996094A364C3_1_0">&lt;div&gt;
 &lt;p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Segment Information&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Operating segments are components of an enterprise for which
 separate financial information is available and is evaluated
 regularly by the Company&amp;#x2019;s chief operating decision maker in
 deciding how to allocate resources and assessing performance. The
 Company&amp;#x2019;s chief operating decision maker is its Chief
 Executive Officer.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company&amp;#x2019;s Chief Executive Officer views the
 Company&amp;#x2019;s operations and manages its business in one
 operating segment, which is the business of researching, developing
 and commercializing therapies for the treatment of patients with
 cancer. Accordingly, the Company has a single reporting
 segment.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:SegmentReportingPolicyPolicyTextBlock>
  <us-gaap:ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_AF8CDFD7-3C65-4B70-92A9-B3EA8BC7750E_1_0">&lt;div&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 As of March&amp;#xA0;31, 2018, the aggregate future &lt;font style="white-space:nowrap"&gt;non-cancelable&lt;/font&gt; minimum lease payments
 associated with these operating leases are as follows:&lt;/p&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table cellspacing="0" cellpadding="0" width="68%" border="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" align="center"&gt;
 &lt;tr&gt;
 &lt;td width="81%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="14%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;
 &lt;p style="margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; width:96.20pt; display:inline; font-size:8pt; font-family:Times New Roman;"&gt;
 &lt;b&gt;Years Ending December&amp;#xA0;31:&lt;/b&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;
 &lt;b&gt;Operating&amp;#xA0;Leases&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center"&gt;
 &lt;b&gt;(in&amp;#xA0;thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Remainder of 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;307&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2019&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;266&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2020&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;220&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2021&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;223&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 2022&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;178&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Thereafter&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom" align="right"&gt;
 &amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:3.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Total &lt;sup style="font-size:85%; vertical-align:top"&gt;(a)&lt;/sup&gt;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,194&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;(a)&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;Minimum lease payments have not been
 reduced by minimum sublease rentals of $0.1&amp;#xA0;million due in the
 future under sublease.&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock>
  <us-gaap:ScheduleOfRestructuringAndRelatedCostsTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_32483A0F-E9D1-4F56-AA9C-E06BE3FA24CA_1_0">&lt;div&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The following table summarizes restructuring activities for the
 three months ended March&amp;#xA0;31, 2018:&lt;/p&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table cellspacing="0" cellpadding="0" width="68%" border="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" align="center"&gt;
 &lt;tr&gt;
 &lt;td width="84%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="13%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;&lt;b&gt;Contract&lt;br /&gt;
 Termination&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center"&gt;
 &lt;b&gt;(in&amp;#xA0;thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Accrual balance at December&amp;#xA0;31, 2017&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;137&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Cash payments&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(38&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:3.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Accrual balance at March&amp;#xA0;31, 2018&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:ScheduleOfRestructuringAndRelatedCostsTextBlock>
  <us-gaap:ShareBasedCompensation contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_3" unitRef="iso4217_USD">1499000</us-gaap:ShareBasedCompensation>
  <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="2" id="id_12173116_3F4066BD-A92B-4F37-8C36-50760899EF04_1_3" unitRef="pure">0.91</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum>
  <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="2" id="id_12173116_3F4066BD-A92B-4F37-8C36-50760899EF04_1_6" unitRef="pure">0.00</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate>
  <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="2" id="id_12173116_3F4066BD-A92B-4F37-8C36-50760899EF04_1_2" unitRef="pure">0.88</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum>
  <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="3" id="id_12173116_3F4066BD-A92B-4F37-8C36-50760899EF04_1_4" unitRef="pure">0.027</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum>
  <us-gaap:ShareBasedCompensationOptionAndIncentivePlansPolicy contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_2C87DC13-4A64-4833-9255-E8C238E3660E_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Stock-Based Compensation&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company accounts for stock-based payments at fair value, which
 is measured using the Black-Scholes option-pricing model. For
 stock-based awards that vest subject to the satisfaction of a
 service requirement, the fair value measurement date for employee
 stock-based compensation awards is the date of grant and the
 expense is recognized on a straight-line basis over the vesting
 period.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 For stock-based awards that vest subject to the satisfaction of a
 service requirement and a performance component, the fair value
 measurement date is the date of grant and is recognized over the
 requisite service period as achievement of the performance
 objective becomes probable.&lt;/p&gt;
 &lt;p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 Stock-based compensation arrangements with &lt;font style="white-space:nowrap"&gt;non-employees&lt;/font&gt; are recognized at the
 grant date and remeasured to fair value at each reporting period.
 The expense is recognized over the vesting period, which is
 generally the service period.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:ShareBasedCompensationOptionAndIncentivePlansPolicy>
  <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="3" id="id_12173116_3F4066BD-A92B-4F37-8C36-50760899EF04_1_5" unitRef="pure">0.028</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum>
  <us-gaap:StockholdersEquityNoteDisclosureTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_185CFBD6-C085-4849-922D-20AEE0AE16DB_1_0">&lt;div&gt;
 &lt;table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" border="0" cellpadding="0" cellspacing="0" width="100%"&gt;
 &lt;tr style="page-break-inside:avoid"&gt;
 &lt;td width="4%" valign="top" align="left"&gt;&lt;b&gt;7.&lt;/b&gt;&lt;/td&gt;
 &lt;td align="left" valign="top"&gt;&lt;b&gt;Common Stock Reserved for
 Issuance&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The Company is required to reserve and keep available out of its
 authorized but unissued shares of common stock a number of shares
 sufficient to effect the conversion of all outstanding options
 granted and available for grant under the incentive plans and
 shares reserved for issuance under the employee stock purchase
 plan.&lt;/p&gt;
 &lt;p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table cellspacing="0" cellpadding="0" width="76%" border="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" align="center"&gt;
 &lt;tr&gt;
 &lt;td width="73%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="2" align="center" style="border-bottom:1.00pt solid #000000"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Outstanding stock options&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;10,202,831&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;7,470,601&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Shares reserved for future option grants&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;802,890&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,503,770&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr bgcolor="#CCEEFF" style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Shares reserved under the 2015 employee stock purchase plan&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;700,000&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;700,000&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:1.00px solid #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt"&gt;
 &lt;td valign="top"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; margin-left:3.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"&gt;
 Total common stock reserved for issuance&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;11,705,721&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;9,674,371&lt;/td&gt;
 &lt;td nowrap="nowrap" valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="font-size:1px;"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style=" margin-top:0pt ; margin-bottom:0pt; border-top:3.00px double #000000"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:StockholdersEquityNoteDisclosureTextBlock>
  <us-gaap:SignificantAccountingPoliciesTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_44D84C94-6D41-44C5-AD2E-294B81AB6098_1_0">&lt;div&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="100%" border="0"&gt;
 &lt;tr style="PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top" width="4%" align="left"&gt;&lt;b&gt;2.&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="top" align="left"&gt;&lt;b&gt;Summary of Significant Accounting
 Policies&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 &lt;b&gt;Basis of Presentation&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The condensed consolidated balance sheet as of March&amp;#xA0;31, 2018,
 the condensed consolidated statements of operations for the three
 months ended March&amp;#xA0;31, 2018 and 2017, the condensed
 consolidated statements of cash flows for the three months ended
 March&amp;#xA0;31, 2018 and 2017 and the condensed consolidated
 statement of stockholders&amp;#x2019; equity as of March&amp;#xA0;31, 2018
 are unaudited. The unaudited condensed consolidated financial
 statements have been prepared on the same basis as the annual
 consolidated financial statements and reflect, in the opinion of
 management, all adjustments of a normal and recurring nature that
 are necessary for the fair presentation of the Company&amp;#x2019;s
 condensed consolidated financial statements included in this
 report. The condensed consolidated financial data disclosed in
 these notes to the condensed consolidated financial statements
 related to the three-month periods are also unaudited. The
 condensed consolidated results of operations for the three months
 ended March&amp;#xA0;31, 2018 are not necessarily indicative of the
 results to be expected for the year ending December&amp;#xA0;31, 2018,
 or for any other future annual or interim period. The condensed
 consolidated balance sheet as of December&amp;#xA0;31, 2017 included
 herein was derived from the audited consolidated financial
 statements as of that date. These condensed consolidated financial
 statements should be read in conjunction with the Company&amp;#x2019;s
 audited consolidated financial statements included in the
 Company&amp;#x2019;s Annual Report on Form &lt;font style="WHITE-SPACE: nowrap"&gt;10-K&lt;/font&gt; for the year ended
 December&amp;#xA0;31, 2017, filed with the SEC on February&amp;#xA0;27,
 2018.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Use of Estimates&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The preparation of the condensed consolidated financial statements
 in conformity with U.S. generally accepted accounting principles
 requires management to make estimates and assumptions that affect
 the reported amounts of assets and liabilities and disclosure of
 contingent assets and liabilities at the date of the condensed
 consolidated financial statements and the reported amounts of
 expense during the reporting period. Significant estimates and
 assumptions made in the accompanying condensed consolidated
 financial statements include, but are not limited to the fair value
 of stock options issued, accruals such as research and development
 costs, and recoverability of the Company&amp;#x2019;s net deferred tax
 assets and related valuation allowance. The Company evaluates its
 estimates and assumptions on an ongoing basis using historical
 experience and other factors and adjusts those estimates and
 assumptions when facts and circumstances dictate. Actual results
 could materially differ from those estimates.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0px; FONT-SIZE: 1px; MARGIN-TOP: 18px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 0pt"&gt;
 &lt;b&gt;Foreign Currency&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The functional currency of the Company&amp;#x2019;s foreign subsidiaries
 is the U.S.&amp;#xA0;Dollar. Transactions denominated in currencies
 other than the functional currency are recorded at prevailing
 exchange rates during the period. At the end of each reporting
 period, monetary assets and liabilities are remeasured to the
 functional currency using exchange rates in effect at the balance
 sheet date. &lt;font style="WHITE-SPACE: nowrap"&gt;Non-monetary&lt;/font&gt;
 assets and liabilities are recorded at historical exchange rates.
 Gains and losses related to remeasurement are recorded in other
 income in the condensed consolidated statements of operations. The
 net foreign exchange transaction gains (losses) included in other
 income in the accompanying condensed consolidated statements of
 operations was insignificant for the three months ended
 March&amp;#xA0;31, 2018 and 2017.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Cash and Cash Equivalents&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company considers all highly liquid investments with an
 original maturity of three months or less from the date of purchase
 to be cash equivalents. Cash and cash equivalents consist primarily
 of funds invested in readily available checking and savings
 accounts and highly liquid investments in money market funds.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Restricted Cash&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Restricted cash, which consists of funds invested in a money market
 fund, represents collateral for a corporate credit card facility.
 Restricted cash at December&amp;#xA0;31, 2017 also included security
 deposits required for a facility lease that expired in February
 2018.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Concentrations of Credit Risk&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Financial instruments that subject the Company to significant
 concentrations of credit risk consist of cash, cash equivalents and
 restricted cash. All of the Company&amp;#x2019;s cash, cash equivalents
 and restricted cash are held at financial institutions in the
 United States and Canada that management believes to be of high
 credit quality. Deposits held in the United States and Canada with
 these financial institutions exceed federally insured limits.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The primary focus of the Company&amp;#x2019;s investment strategy is to
 preserve capital and meet liquidity requirements. The
 Company&amp;#x2019;s investment policy addresses the level of credit
 exposure by limiting the concentration in any one corporate issuer
 and establishing a minimum allowable credit rating.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Comprehensive Loss&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company had no components of comprehensive loss other than net
 loss for all periods presented.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Fair Value of Financial Instruments&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company&amp;#x2019;s cash and cash equivalents, restricted cash,
 other current assets, accounts payable, and accrued liabilities
 approximate their fair value at March&amp;#xA0;31, 2018 and
 December&amp;#xA0;31, 2017, due to their short duration.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The Company utilizes valuation techniques that maximize the use of
 observable inputs and minimize the use of unobservable inputs to
 the extent possible. The Company determines the fair value of its
 financial instruments based on assumptions that market participants
 would use in pricing an asset or liability in the principal or most
 advantageous market. When considering market participant
 assumptions in fair value measurements, the following fair value
 hierarchy distinguishes between observable and unobservable inputs,
 which are categorized in one of the following levels:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 4%; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;Level&lt;/i&gt;&lt;i&gt;&amp;#xA0;1&lt;/i&gt; &amp;#x2013; Inputs are unadjusted quoted
 prices in active markets for identical assets or liabilities at the
 measurement date;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 4%; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;Level&lt;/i&gt;&lt;i&gt;&amp;#xA0;2&lt;/i&gt; &amp;#x2013; Inputs are observable,
 unadjusted quoted prices in active markets for similar assets or
 liabilities, unadjusted quoted prices for identical or similar
 assets or liabilities in markets that are not active, or other
 inputs that are observable or can be corroborated by observable
 market data for substantially the full term of the related assets
 or liabilities; and&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 4%; MARGIN-TOP: 6pt"&gt;
 &lt;i&gt;Level&lt;/i&gt;&lt;i&gt;&amp;#xA0;3&lt;/i&gt; &amp;#x2013; Unobservable inputs that are
 significant to the measurement of the fair value of the assets or
 liabilities that are supported by little or no market data.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0px; FONT-SIZE: 1px; MARGIN-TOP: 18px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 0pt"&gt;
 &lt;b&gt;Property and Equipment, Net&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Property and equipment, net are stated at cost, less accumulated
 depreciation. Depreciation on property and equipment, excluding
 leasehold improvements, is computed using the straight-line method
 over the estimated useful lives of the respective assets, generally
 three to five years. Depreciation begins at the time the asset is
 placed in service. Maintenance and repairs are charged to
 operations as incurred. Upon sale or retirement of assets, the cost
 and related accumulated depreciation are removed from the condensed
 consolidated balance sheet and the resulting gain or loss is
 reflected in the condensed consolidated statement of operations.
 Leasehold improvements are amortized on a straight-line basis over
 the shorter of the estimated useful lives of the assets or the
 remaining lease term.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Other Assets&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Other assets consist primarily of restricted cash pledged as
 collateral for a corporate credit card facility, and long-term
 prepaid rent and refundable deposits on office leases.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Research and Development Costs&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Research and development costs are expensed as incurred. The
 Company accounts for &lt;font style="WHITE-SPACE: nowrap"&gt;non-refundable&lt;/font&gt; advance payments for
 goods and services that will be used in future research and
 development activities as expenses when the goods have been
 received or when the service has been performed rather than when
 the payment is made. Depending on the timing of payments to service
 providers of research and development costs, the Company recognizes
 prepaid expenses or accrued expenses related to these costs. These
 prepaid or accrued expenses are based on management&amp;#x2019;s
 estimates of the work performed under service agreements and
 milestones achieved. In the event that a clinical trial is
 terminated early, the Company records an accrual for the estimated
 remaining costs to complete the trial in the period of
 termination.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 Upfront payments made in connection with license agreements are
 expensed as research and developments costs, as the assets acquired
 do not have alterative future use. Contingent milestone payment
 obligations due to third parties under license agreements are
 expensed when the milestones are considered probable of
 occurring.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 Research and development costs include fees incurred in connection
 with license agreements, compensation and other related costs for
 employees engaged in&amp;#xA0;research and development, costs
 associated with research and preclinical studies, clinical trials,
 regulatory activities, manufacturing activities to support clinical
 activities, fees paid to external service providers that conduct
 certain research and development, clinical, and manufacturing
 activities on behalf of the Company and an allocation of overhead
 expenses.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Stock-Based Compensation&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company accounts for stock-based payments at fair value, which
 is measured using the Black-Scholes option-pricing model. For
 stock-based awards that vest subject to the satisfaction of a
 service requirement, the fair value measurement date for employee
 stock-based compensation awards is the date of grant and the
 expense is recognized on a straight-line basis over the vesting
 period.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 For stock-based awards that vest subject to the satisfaction of a
 service requirement and a performance component, the fair value
 measurement date is the date of grant and is recognized over the
 requisite service period as achievement of the performance
 objective becomes probable.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 Stock-based compensation arrangements with &lt;font style="WHITE-SPACE: nowrap"&gt;non-employees&lt;/font&gt; are recognized at the
 grant date and remeasured to fair value at each reporting period.
 The expense is recognized over the vesting period, which is
 generally the service period.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Income Taxes&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 The Company uses the asset and liability method of accounting for
 income taxes. Under this method, deferred tax assets and
 liabilities are determined based on the differences between the
 financial reporting and the tax bases of assets and liabilities and
 are measured using the enacted tax rates and laws that will be in
 effect when the differences are expected to reverse. Management
 makes an assessment of the likelihood that the resulting deferred
 tax assets will be realized. A valuation allowance is provided when
 it is more likely than not that some portion or all of a deferred
 tax asset will not be realized. Due to the Company&amp;#x2019;s
 historical operating performance and the recorded cumulative net
 losses in prior fiscal periods, the net U.S. deferred tax assets
 have been offset by a full valuation allowance.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The Company recognizes uncertain income tax positions at the
 largest amount that is more likely than not to be sustained upon
 audit by the relevant taxing authority. An uncertain income tax
 position will not be recognized if it has less than a 50%
 likelihood of being sustained. Changes in recognition or
 measurement are reflected in the period in which judgment occurs.
 The Company recognizes interest and penalties related to the
 underpayment of income taxes as a component of provision for income
 taxes.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0px; FONT-SIZE: 1px; MARGIN-TOP: 18px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 0pt"&gt;
 &lt;b&gt;Segment Information&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Operating segments are components of an enterprise for which
 separate financial information is available and is evaluated
 regularly by the Company&amp;#x2019;s chief operating decision maker in
 deciding how to allocate resources and assessing performance. The
 Company&amp;#x2019;s chief operating decision maker is its Chief
 Executive Officer.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The Company&amp;#x2019;s Chief Executive Officer views the
 Company&amp;#x2019;s operations and manages its business in one
 operating segment, which is the business of researching, developing
 and commercializing therapies for the treatment of patients with
 cancer. Accordingly, the Company has a single reporting
 segment.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Recent Accounting Pronouncements Not Yet Effective&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 In February 2016, the Financial Accounting Standards Board (FASB)
 issued FASB Accounting Standards Update (ASU) &lt;font style="WHITE-SPACE: nowrap"&gt;No.&amp;#xA0;2016-02,&lt;/font&gt; &lt;i&gt;Leases (Topic
 842)&lt;/i&gt;. The amendments in this update require that organizations
 recognize lease assets and lease liabilities on the balance sheet
 and disclose key information about leasing arrangements. This ASU
 is effective for financial statements issued for fiscal years
 beginning after December&amp;#xA0;15, 2018, and interim periods within
 those fiscal years, with early adoption permitted. The Company will
 adopt the new standard effective January&amp;#xA0;1, 2019 and expects
 its operating leases, as disclosed in Note 6 &amp;#x201C;Commitments and
 Contingencies&amp;#x201D;, to be subject to the new standard. The
 Company will &lt;font style="WHITE-SPACE: nowrap"&gt;&lt;font style="WHITE-SPACE: nowrap"&gt;recognize&amp;#xA0;right-of-use&amp;#xA0;assets&lt;/font&gt;&lt;/font&gt;
 and operating lease liabilities on its consolidated balance sheets
 upon adoption, which will increase its total assets and
 liabilities.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:SignificantAccountingPoliciesTextBlock>
  <us-gaap:StockIssuedDuringPeriodValueNewIssues contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_ED45E2BF-7FB1-4C0F-A33E-0298F12938E5_5005_6" unitRef="iso4217_USD">45996000</us-gaap:StockIssuedDuringPeriodValueNewIssues>
  <us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_ED45E2BF-7FB1-4C0F-A33E-0298F12938E5_5005_3" unitRef="iso4217_USD">101000</us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised>
  <us-gaap:SupplementalBalanceSheetDisclosuresTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_3EACDF32-0FA1-4734-BF93-6DBC071384FA_1_0">&lt;div&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="100%" border="0"&gt;
 &lt;tr style="PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top" width="4%" align="left"&gt;&lt;b&gt;5.&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="top" align="left"&gt;&lt;b&gt;Balance Sheet Components&lt;/b&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 &lt;b&gt;Cash and Cash Equivalents&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Cash and cash equivalents consist of the following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="74%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="6%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="6%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;/b&gt;&lt;br /&gt;
 &lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Cash&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;381&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;556&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Cash equivalents:&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Money market accounts&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99,792&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total cash and cash equivalents&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,829&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;100,348&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 In November 2016, the FASB issued new guidance ASU &lt;font style="WHITE-SPACE: nowrap"&gt;No.&amp;#xA0;2016-18,&lt;/font&gt; &lt;i&gt;Statement of Cash
 Flows (Topic 230): Restricted Cash&lt;/i&gt;, which requires the
 &lt;font style="WHITE-SPACE: nowrap"&gt;&lt;font style="WHITE-SPACE: nowrap"&gt;beginning-of-period&lt;/font&gt;&lt;/font&gt; and
 &lt;font style="WHITE-SPACE: nowrap"&gt;&lt;font style="WHITE-SPACE: nowrap"&gt;end-of-period&lt;/font&gt;&lt;/font&gt; totals on the
 statement of cash flows to include restricted cash and restricted
 cash equivalents, as well as disclosure of how the statement of
 cash flows reconciles to the balance sheet if restricted cash is
 shown separately from cash and cash equivalents on the balance
 sheet. The company adopted the guidance effective January&amp;#xA0;1,
 2018 retrospectively to all periods presented. As a result, the
 condensed consolidated statement of cash flows no longer presents
 transfers to or from restricted cash.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The following table provides a reconciliation of cash, cash
 equivalents and restricted cash reported in the condensed
 consolidated balance sheets to the amounts shown in the condensed
 consolidated statements of cash flows.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="78%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;/b&gt;&lt;br /&gt;
 &lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Cash and cash equivalents&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,829&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;125,025&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Restricted cash included in other assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;175&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;187&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total cash, cash equivalents and restricted cash shown in the
 condensed consolidated statement of cash flows&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;134,004&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;125,212&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Prepaid Expenses and Other Current Assets&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Prepaid expenses and other current assets consist of the
 following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="76%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Prepaid research and development project costs&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,242&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;549&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Prepaid insurance&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;276&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;478&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Other receivables&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;328&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;103&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Other&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;313&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;247&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total prepaid expenses and other current assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,159&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;1,377&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0px; FONT-SIZE: 1px; MARGIN-TOP: 18px"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 0pt"&gt;
 &lt;b&gt;Property and Equipment, net&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Property and equipment, net consists of the following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="76%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="9%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="9%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Software&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;273&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;254&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Computer equipment&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;93&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;93&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Leasehold improvements&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;79&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;79&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Furniture and fixtures&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;3&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Property and equipment, gross&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;448&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;429&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Less: accumulated depreciation&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(304&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;(275&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;)&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 5em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total property and equipment, net&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;144&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;154&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 Depreciation related to the Company&amp;#x2019;s property and equipment
 was $29,000 and $0.1&amp;#xA0;million for the three months ended
 March&amp;#xA0;31, 2018 and 2017, respectively.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 18pt"&gt;
 &lt;b&gt;Accrued Liabilities&lt;/b&gt;&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 6pt"&gt;
 Accrued liabilities consist of the following:&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="76%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;December&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued research and development costs&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,994&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,763&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued employee-related costs&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;862&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;2,699&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued professional fees&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;753&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;317&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Accrued restructuring costs (Note 10)&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;99&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;137&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Other&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;190&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;217&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total accrued liabilities&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;4,898&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;6,133&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;/table&gt;
 &lt;/div&gt;</us-gaap:SupplementalBalanceSheetDisclosuresTextBlock>
  <dei:TradingSymbol contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_8CE924CE-1C99-4F12-B286-90DAADA61E8B_1_0">SRRA</dei:TradingSymbol>
  <us-gaap:WeightedAverageNumberOfShareOutstandingBasicAndDiluted contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="0" id="id_12173116_808E0921-4417-4C90-A966-9BD7EE519419_1_10" unitRef="shares">59722743</us-gaap:WeightedAverageNumberOfShareOutstandingBasicAndDiluted>
  <us-gaap:UseOfEstimates contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_0BF71F4B-F3D4-41EE-8FA7-B600B438C7BC_1_0">&lt;div&gt;
 &lt;p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 &lt;b&gt;Use of Estimates&lt;/b&gt;&lt;/p&gt;
 &lt;p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;
 The preparation of the condensed consolidated financial statements
 in conformity with U.S. generally accepted accounting principles
 requires management to make estimates and assumptions that affect
 the reported amounts of assets and liabilities and disclosure of
 contingent assets and liabilities at the date of the condensed
 consolidated financial statements and the reported amounts of
 expense during the reporting period. Significant estimates and
 assumptions made in the accompanying condensed consolidated
 financial statements include, but are not limited to the fair value
 of stock options issued, accruals such as research and development
 costs, and recoverability of the Company&amp;#x2019;s net deferred tax
 assets and related valuation allowance. The Company evaluates its
 estimates and assumptions on an ongoing basis using historical
 experience and other factors and adjusts those estimates and
 assumptions when facts and circumstances dictate. Actual results
 could materially differ from those estimates.&lt;/p&gt;
 &lt;/div&gt;</us-gaap:UseOfEstimates>
  <srra:StockIssuanceCostsIncurredButNotYetPaid contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" decimals="-3" id="id_12173116_17B01CD6-8670-4658-808B-35D1740DC8AB_1_26" unitRef="iso4217_USD">209000</srra:StockIssuanceCostsIncurredButNotYetPaid>
  <srra:ScheduleOfCashCashEquivalentsAndRestrictedCashTableTextBlock contextRef="eol_PE635290--1810-Q0003_STD_90_20180331_0" id="id_12173116_3D1A9402-C35D-41FD-A570-5772F4540D36_1_0">&lt;div&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-TOP: 12pt"&gt;
 The following table provides a reconciliation of cash, cash
 equivalents and restricted cash reported in the condensed
 consolidated balance sheets to the amounts shown in the condensed
 consolidated statements of cash flows.&lt;/p&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 12pt; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;table style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; BORDER-COLLAPSE: collapse" cellspacing="0" cellpadding="0" width="76%" align="center" border="0"&gt;
 &lt;tr&gt;
 &lt;td width="78%"&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td valign="bottom" width="4%"&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;td&gt;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;/b&gt;&lt;br /&gt;
 &lt;b&gt;2018&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td style="BORDER-BOTTOM: #000000 1pt solid" valign="bottom" colspan="2" align="center"&gt;&lt;b&gt;March&amp;#xA0;31,&lt;br /&gt;
 2017&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" colspan="6" align="center"&gt;&lt;b&gt;(in
 thousands)&lt;/b&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Cash and cash equivalents&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;133,829&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;125,025&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 1em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Restricted cash included in other assets&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;175&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;187&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 1px solid; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; PAGE-BREAK-INSIDE: avoid" bgcolor="#CCEEFF"&gt;
 &lt;td valign="top"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman; MARGIN-LEFT: 3em; MARGIN-TOP: 0pt; TEXT-INDENT: -1em"&gt;
 Total cash, cash equivalents and restricted cash shown in the
 condensed consolidated statement of cash flows&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;134,004&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;$&lt;/td&gt;
 &lt;td valign="bottom" align="right"&gt;125,212&lt;/td&gt;
 &lt;td valign="bottom" nowrap="nowrap"&gt;&amp;#xA0;&lt;/td&gt;
 &lt;/tr&gt;
 &lt;tr style="FONT-SIZE: 1px"&gt;
 &lt;td valign="bottom"&gt;&lt;/td&gt;
 &lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
 &lt;td valign="bottom"&gt;
 &lt;p style="MARGIN-BOTTOM: 0pt; BORDER-TOP: #000000 3px double; MARGIN-TOP: 0pt"&gt;
 &amp;#xA0;&lt;/p&gt;
 &lt;/td&gt;
 &lt;td valign="bottom"&gt;
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