Consolidated Consolidated Statements of Operations (Current Period Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating expenses
Research and development	$ 3,553,000	$ 3,705,000	$ 7,302,000	$ 7,213,000
General and administrative	3,552,000	4,088,000	6,784,000	7,678,000
Total operating expenses	7,105,000	7,793,000	14,086,000	14,891,000
Operating loss	(7,105,000)	(7,793,000)	(14,086,000)	(14,891,000)
Impairment charge on investment in equity securities	0	(2,990,000)	0	(2,990,000)
Interest income	1,073,000	983,000	2,211,000	1,833,000
Other expense, net	(17,000)	(30,000)	(52,000)	(63,000)
Loss before income taxes	(6,049,000)	(9,830,000)	(11,927,000)	(16,111,000)
Income taxes benefit	0	0	0	0
Net loss	$ (6,049,000)	$ (9,830,000)	$ (11,927,000)	$ (16,111,000)
Net loss per share of common stock - basic (in dollars per share)	$ (0.05)	$ (0.08)	$ (0.1)	$ (0.13)
Net loss per share of common stock - diluted (in dollars per share)	$ (0.05)	$ (0.08)	$ (0.1)	$ (0.13)
Weighted average shares outstanding used to compute net loss per share- basic (in shares)	125,732,140	126,622,798	125,525,959	126,623,450
Weighted average shares outstanding used to compute net loss per share - diluted (in shares)	125,732,140	126,622,798	125,525,959	126,623,450