Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue from Contract with Customer, Including Assessed Tax	$ 675,000	$ 85,000
Operating expenses:
Research and development	19,622,000	18,203,000
General and administrative	6,625,000	6,658,000
Total operating expenses	26,247,000	24,861,000
Operating loss	(25,572,000)	(24,776,000)
Other income (expense):
Interest income	642,000	35,000
Non-cash interest expense related to sale of future royalties	(178,000)	(340,000)
Foreign exchange loss, net	(3,000)	0
Loss before income taxes	(25,111,000)	(25,081,000)
Provision for income taxes	29,000	20,000
Net loss	$ (25,140,000)	$ (25,101,000)
Net loss per share - basic and diluted (in dollars per share)	$ (0.19)	$ (0.20)
Shares used to compute net loss per share - basic and diluted (in shares)	135,213,196	125,795,255
Comprehensive loss:
Net loss	$ (25,140,000)	$ (25,101,000)
Unrealized gain (loss) on available-for-sale investments, net of tax	229,000	(235,000)
Comprehensive loss	(24,911,000)	(25,336,000)
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	278,000	85,000
Grant [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 397,000	$ 0