Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue from Contract with Customer, Including Assessed Tax	$ 112,000	$ 523,000	$ 618,000	$ 3,425,000
Operating expenses:
Research and development	10,737,000	5,114,000	20,810,000	6,656,000
General and administrative	5,150,000	3,896,000	11,094,000	5,886,000
Restructuring costs	0	39,000	0	103,000
Total operating expenses	15,887,000	9,049,000	31,904,000	12,645,000
Operating loss	(15,775,000)	(8,526,000)	(31,286,000)	(9,220,000)
Other income and (expenses):
Interest income	23,000	23,000	32,000	64,000
Non-cash interest expense related to sale of future royalties	(334,000)	(446,000)	(800,000)	(937,000)
Foreign exchange loss, net	0	(2,000)	(1,000)	(2,000)
Loss before income taxes	(16,086,000)	(8,951,000)	(32,055,000)	(10,095,000)
Provision for income taxes	30,000	26,000	68,000	179,000
Net loss	$ (16,116,000)	$ (8,977,000)	$ (32,123,000)	$ (10,274,000)
Net loss per share - basic and diluted (in dollars per share)	$ (0.13)	$ (0.12)	$ (0.27)	$ (0.15)
Shares used to compute net loss per share - basic and diluted (in shares)	120,925,570	74,675,131	118,174,099	67,676,138
Comprehensive loss:
Net loss	$ (16,116,000)	$ (8,977,000)	$ (32,123,000)	$ (10,274,000)
Unrealized loss on available-for-sale investments	(4,000)	0	(9,000)	0
Comprehensive loss	(16,120,000)	(8,977,000)	(32,132,000)	(10,274,000)
Customer Service Contracts [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	92,000	13,000	191,000
Royalty [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	193,000	0	2,962,000
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 112,000	$ 238,000	$ 605,000	$ 272,000