Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer, Including Assessed Tax	$ 2,101	$ 0	$ 4,134	$ 85
Operating expenses:
Research and development	15,002	22,466	53,437	60,595
General and administrative	4,921	6,960	17,144	22,939
Total operating expenses	19,923	29,426	70,581	83,534
Operating loss	(17,822)	(29,426)	(66,447)	(83,449)
Other income (expense):
Interest income	723	458	2,076	650
Non-cash interest expense related to sale of future royalties	(207)	(325)	(573)	(988)
Other expense, net	(55)	0	(59)	(2)
Loss before income taxes	(17,361)	(29,293)	(65,003)	(83,789)
Provision for income taxes	39	16	87	51
Net loss	$ (17,400)	$ (29,309)	$ (65,090)	$ (83,840)
Net loss per share - basic and diluted (in dollars per share)	$ (0.11)	$ (0.23)	$ (0.45)	$ (0.66)
Shares used to compute net loss per share - basic and diluted (in shares)	152,026,112	126,889,718	145,810,175	126,374,424
Comprehensive loss:
Net loss	$ (17,400)	$ (29,309)	$ (65,090)	$ (83,840)
Unrealized gain (loss) on available-for-sale investments, net of tax	13	(109)	288	(444)
Comprehensive loss	(17,387)	(29,418)	(64,802)	(84,284)
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	446	0	754	85
Grant [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,655	$ 0	$ 3,380	$ 0