Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue:
Revenues	$ 4,933	$ 2,101	$ 13,515	$ 4,134
Operating expenses:
Research and development	15,066	15,002	51,559	53,437
General and administrative	4,342	4,921	16,757	17,144
Total operating expenses	19,408	19,923	68,316	70,581
Operating loss	(14,475)	(17,822)	(54,801)	(66,447)
Other income (expense):
Interest income	1,022	723	1,941	2,076
Non-cash interest expense related to sale of future royalties	(631)	(207)	(2,045)	(573)
Other income (expense), net	22	(55)	26	(59)
Loss before income taxes	(14,062)	(17,361)	(54,879)	(65,003)
Provision for income taxes	18	39	84	87
Net loss	$ (14,080)	$ (17,400)	$ (54,963)	$ (65,090)
Net loss per share - basic and diluted (in dollars per share)	$ (0.06)	$ (0.11)	$ (0.28)	$ (0.45)
Shares used to compute net loss per share - basic and diluted (in shares)	227,452,883	152,026,112	193,655,660	145,810,175
Comprehensive loss:
Net loss	$ (14,080)	$ (17,400)	$ (54,963)	$ (65,090)
Unrealized gain on available-for-sale investments, net of tax	43	13	28	288
Comprehensive loss	(14,037)	(17,387)	(54,935)	(64,802)
Non Cash Royalty Revenue [Member]
Revenue:
Revenues	40	446	662	754
Government Contract [Member]
Revenue:
Revenues	4,893	0	12,853	0
Grant [Member]
Revenue:
Revenues	$ 0	$ 1,655	$ 0	$ 3,380