Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating expenses
Research and development	$ 4,467	$ 5,160	$ 11,680	$ 10,097
General and administrative	3,001	3,045	10,678	9,456
Total operating expenses	7,468	8,205	22,358	19,553
Operating loss	(7,468)	(8,205)	(22,358)	(19,553)
Impairment charge on investment in equity securities	0	0	(2,990)	0
Interest income	1,274	194	3,107	207
Other expense, net	(35)	0	(99)	(123)
Loss before income taxes	(6,229)	(8,011)	(22,340)	(19,469)
Income taxes	0	0	0	0
Net loss	(6,229)	(8,011)	(22,340)	(19,469)
Foreign currency translation adjustment	0	(54)	0	(54)
Comprehensive loss	$ (6,229)	$ (8,065)	$ (22,340)	$ (19,523)
Loss per share of common stock - basic and diluted (in dollars per share)	$ (0.05)	$ (0.06)	$ (0.18)	$ (0.15)
Weighted average shares outstanding - basic and diluted (in shares)	125,793	126,624	126,344	126,624