Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue from Contract with Customer, Including Assessed Tax	$ 0	$ 112	$ 85	$ 618
Operating expenses:
Research and development	19,926	10,737	38,129	20,810
General and administrative	9,321	5,150	15,979	11,094
Total operating expenses	29,247	15,887	54,108	31,904
Operating loss	(29,247)	(15,775)	(54,023)	(31,286)
Other income (expense):
Interest income, net	157	23	192	32
Non-cash interest expense related to sale of future royalties	(323)	(334)	(663)	(800)
Foreign exchange loss, net	(2)	0	(2)	(1)
Loss before income taxes	(29,415)	(16,086)	(54,496)	(32,055)
Provision for income taxes	15	30	35	68
Net loss	$ (29,430)	$ (16,116)	$ (54,531)	$ (32,123)
Net loss per share - basic and diluted (in dollars per share)	$ (0.23)	$ (0.13)	$ (0.43)	$ (0.27)
Shares used to compute net loss per share - basic and diluted (in shares)	126,428,298	120,925,570	126,111,777	118,174,099
Comprehensive loss:
Net loss	$ (29,430)	$ (16,116)	$ (54,531)	$ (32,123)
Unrealized loss on available-for-sale investments, net of tax	(100)	(4)	(335)	(9)
Comprehensive loss	(29,530)	(16,120)	(54,866)	(32,132)
Customer Service Contracts [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	0	0	13
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 0	$ 112	$ 85	$ 605