CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 18,189	$ 13,281	$ 46,501	$ 37,407
Operating expenses:
Research and development	24,685	21,015	75,014	88,467
General and administrative	10,231	9,208	28,862	28,686
Restructuring charge		1,020	1,524	20,921
Total operating expenses	34,916	31,243	105,400	138,074
Loss from operations	(16,727)	(17,962)	(58,899)	(100,667)
Investment income, net	11	1,032	719	3,741
Non-cash interest expense on liability related to the sale of future royalties and convertible senior notes	(5,645)	(4,275)	(17,428)	(11,525)
Interest expense on convertible senior notes	(24)	(24)	(71)	(71)
Other income (expense), net	11	(521)	(81)	(425)
Net loss	$ (22,374)	$ (21,750)	$ (75,760)	$ (108,947)
Basic and diluted net loss per common share (in dollar per share)	$ (0.13)	$ (0.15)	$ (0.44)	$ (0.74)
Basic and diluted weighted average common shares outstanding (in shares)	174,508	148,479	172,215	148,143
Total comprehensive loss	$ (22,374)	$ (21,750)	$ (75,760)	$ (108,947)
License and milestone fees
Revenues:
Total revenues	97	79	1,325	5,237
Non-cash royalty revenue related to the sale of future royalties
Revenues:
Total revenues	18,087	$ 13,202	45,159	32,102
Research and development support
Revenues:
Total revenues	$ 5		$ 17	$ 68