CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Total revenues	$ 15,025	$ 15,542	$ 28,312	$ 24,126
Operating expenses:
Research and development	22,921	28,559	50,329	67,452
General and administrative	9,767	8,700	18,631	19,478
Restructuring charge	699	19,342	1,524	19,901
Total operating expenses	33,387	56,601	70,484	106,831
Loss from operations	(18,362)	(41,059)	(42,172)	(82,705)
Investment income, net	62	1,287	708	2,709
Non-cash interest expense on liability related to the sale of future royalties and convertible senior notes	(6,081)	(3,818)	(11,783)	(7,250)
Interest expense on convertible senior notes	(23)	(23)	(47)	(47)
Other income (expense), net	106	167	(92)	96
Net loss	$ (24,298)	$ (43,446)	$ (53,386)	$ (87,197)
Basic and diluted net loss per common share (in dollar per share)	$ (0.14)	$ (0.29)	$ (0.31)	$ (0.59)
Basic and diluted weighted average common shares outstanding (in shares)	174,354	148,129	171,055	147,972
Total comprehensive loss	$ (24,298)	$ (43,446)	$ (53,386)	$ (87,197)
License and milestone fees
Revenues:
Total revenues	945	5,079	1,228	5,158
Non-cash royalty revenue related to the sale of future royalties
Revenues:
Total revenues	14,075	10,412	27,072	18,900
Research and development support
Revenues:
Total revenues	$ 5	$ 51	$ 12	$ 68