CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Total revenues	$ 69	$ 198	$ 271	$ 296
Operating expenses:
Research and development	4,881	7,306	11,004	11,014
General and administrative	2,730	3,288	6,005	7,058
Total operating expenses	7,611	10,594	17,009	18,072
Operating loss	(7,542)	(10,396)	(16,738)	(17,776)
Other income, net	1,795	1,001	2,388	2,140
Loss from continuing operations before income taxes	(5,747)	(9,395)	(14,350)	(15,636)
Income tax expense	0	0	0	0
Loss from continuing operations	(5,747)	(9,395)	(14,350)	(15,636)
Loss from discontinued operations, net of income taxes	(8)	(11)	(16)	(19)
Net loss	$ (5,755)	$ (9,406)	$ (14,366)	$ (15,655)
Loss per share from continuing operations, basic (in dollars per share)	$ (0.13)	$ (0.22)	$ (0.34)	$ (0.37)
Loss per share from continuing operations, diluted (in dollars per share)	(0.13)	(0.22)	(0.34)	(0.37)
Loss per share from discontinued operations, basic (in dollars per share)	0	0	0	0
Loss per share from discontinued operations, diluted (in dollars per share)	0	0	0	0
Loss per share, basic (in dollars per share)	(0.13)	(0.22)	(0.34)	(0.37)
Loss per share, diluted (in dollars per share)	$ (0.13)	$ (0.22)	$ (0.34)	$ (0.37)
Weighted average shares outstanding - basic (in shares)	42,759	42,586	42,716	42,584
Weighted average shares outstanding - diluted (in shares)	42,759	42,586	42,716	42,584
Other comprehensive loss:
Unrealized (losses) gains on marketable securities, net of tax of $0	$ (2)	$ 12	$ (22)	$ (84)
Total other comprehensive (loss) gain	(2)	12	(22)	(84)
Comprehensive loss	$ (5,757)	$ (9,394)	$ (14,388)	$ (15,739)