Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 74,686	$ 81,146
Prepaid expenses and other current assets	469	562
Total current assets	75,155	81,708
Restricted cash	2,386	2,383
Property and equipment, net	739	798
Build-to-suit lease asset	8,829	8,888
Total assets	87,109	93,777
Current liabilities
Accounts payable	809	1,500
Accrued liabilities	2,726	4,093
Total current liabilities	3,535	5,593
Build-to-suit lease obligation	6,944	5,428
Total liabilities	10,479	11,021
Commitments and contingencies (Note 5)
Stockholders' equity
Common stock, $0.0001 par value, 100,000,000 and 100,000,000 shares authorized at March 31, 2018 and December 31, 2017, respectively; 36,069,791 and 35,938,126 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	4	4
Additional paid-in capital	459,839	456,984
Accumulated deficit	(383,213)	(374,232)
Total stockholders' equity	76,630	82,756
Total liabilities and stockholders’ equity	$ 87,109	$ 93,777

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).