Consolidated Consolidated Statements of Operations (Current Period Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses
Research and development	$ 3,412	$ 4,467	$ 10,714	$ 11,680
General and administrative	2,973	3,001	9,756	10,678
Total operating expenses	6,385	7,468	20,470	22,358
Operating loss	(6,385)	(7,468)	(20,470)	(22,358)
Impairment charge on investment in equity securities	(1,710)	0	(1,710)	(2,990)
Interest income	1,001	1,274	3,213	3,107
Other expense, net	(136)	(35)	(190)	(99)
Loss before income taxes	(7,230)	(6,229)	(19,157)	(22,340)
Income taxes benefit	0	0	0	0
Net loss	$ (7,230)	$ (6,229)	$ (19,157)	$ (22,340)
Net loss per share of common stock - basic (in dollars per share)	$ (0.06)	$ (0.05)	$ (0.15)	$ (0.18)
Net loss per share of common stock - diluted (in dollars per share)	$ (0.06)	$ (0.05)	$ (0.15)	$ (0.18)
Weighted average shares outstanding used to compute net loss per share- basic (in shares)	125,772,664	125,793,112	125,608,794	126,343,629
Weighted average shares outstanding used to compute net loss per share - diluted (in shares)	125,772,664	125,793,112	125,608,794	126,343,629