Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues	$ 6,401	$ 1,358	$ 8,582	$ 2,033
Operating expenses:
Research and development	17,480	18,813	36,493	38,435
General and administrative	5,177	5,598	12,415	12,223
Total operating expenses	22,657	24,411	48,908	50,658
Operating loss	(16,256)	(23,053)	(40,326)	(48,625)
Other income (expense):
Interest income	416	711	919	1,353
Non-cash interest expense related to sale of future royalties	(610)	(188)	(1,414)	(366)
Other income (expense), net	5	(1)	4	(4)
Loss before income taxes	(16,445)	(22,531)	(40,817)	(47,642)
Provision for income taxes	21	19	66	48
Net loss	$ (16,466)	$ (22,550)	$ (40,883)	$ (47,690)
Net loss per share - basic and diluted (in dollars per share)	$ (0.09)	$ (0.16)	$ (0.23)	$ (0.35)
Shares used to compute net loss per share - basic and diluted (in shares)	184,703,003	139,594,238	176,757,049	137,403,416
Comprehensive loss:
Net loss	$ (16,466)	$ (22,550)	$ (40,883)	$ (47,690)
Unrealized (loss) gain on available-for-sale investments, net of tax	(6)	46	(15)	275
Comprehensive loss	(16,472)	(22,504)	(40,898)	(47,415)
Non Cash Royalty Revenue [Member]
Revenues	37	30	622	308
Government Contract [Member]
Revenues	6,364	0	7,960	0
Grant [Member]
Revenues	$ 0	$ 1,328	$ 0	$ 1,725