Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities
Net loss	$ (62,957)	$ (69,037)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,260	3,268
Amortization of intangible assets	417	443
Impairment of property and equipment	1,177
Impairment of intangible assets	5,006
Non-cash lease expense	664
Accretion of discounts and amortization of premiums on marketable securities	(1,371)	(800)
Stock-based compensation	10,114	13,472
Loss from remeasurement of fair value of contingent consideration	25	570
(Gain) loss on disposal of property and equipment	(4)	3
Deferred income tax	(2,320)	(99)
Changes in operating assets and liabilities:
Payment of contingent consideration		(3,322)
Accounts receivable	11,815	989
Income tax receivable		(346)
Prepaid expenses and other assets	671	1,631
Accounts payable	409	(26)
Deferred revenue	(11,468)	(9,246)
Accrued clinical trial and manufacturing expenses	1,483	(2,076)
Accrued expenses and other liabilities	(454)	(3,090)
Operating lease liabilities	94
Net cash used in operating activities	(43,439)	(67,666)
Cash Flows from Investing Activities
Purchase of marketable securities	(224,927)	(179,277)
Proceeds from maturities of marketable securities	196,410	214,314
Purchase of property and equipment	(1,183)	(2,007)
Proceeds from sale of property and equipment		10
Net cash (used in) provided by investing activities	(29,700)	33,040
Cash Flows from Financing Activities
Payment of contingent consideration		(3,481)
Proceeds from employee stock purchase plan	164	366
Proceeds from exercise of stock options and warrants	532	1,328
Net cash provided by (used in) financing activities	696	(1,787)
Effect of exchange rate changes	(262)	(450)
Net decrease in cash, cash equivalents and restricted cash	(72,705)	(36,863)
Cash, cash equivalents and restricted cash at beginning of period	126,778	158,082
Cash, cash equivalents and restricted cash at end of period	54,073	121,219
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Purchase of property and equipment in accounts payable and accrued liabilities	31	363
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash and cash equivalents	53,605	120,751
Restricted cash	468	468
Cash, cash equivalents and restricted cash at end of period	$ 54,073	$ 121,219