Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	4,239	4,278	15,565	12,447
General and administrative	2,243	2,513	7,379	7,342
Total operating expenses	6,482	6,791	22,944	19,789
Loss from operations	(6,482)	(6,791)	(22,944)	(19,789)
Interest income	110	21	180	54
Other income (expense), net	4	66	(18)	370
Net loss	$ (6,368)	$ (6,704)	$ (22,782)	$ (19,365)
Net loss per share - basic	$ (0.07)	$ (0.07)	$ (0.25)	$ (0.22)
Net loss per share - diluted	$ (0.07)	$ (0.07)	$ (0.25)	$ (0.22)
Weighted average common shares outstanding - basic	90,823,597	90,548,972	90,774,146	88,211,362
Weighted average common shares outstanding - diluted	90,823,597	90,548,972	90,774,146	88,211,362
Comprehensive loss:
Net loss	$ (6,368)	$ (6,704)	$ (22,782)	$ (19,365)
Other comprehensive loss:
Unrealized gain (loss) on investments, net of tax of $0	3	(5)	(85)	3
Total other comprehensive income (loss)	3	(5)	(85)	3
Total comprehensive loss	$ (6,365)	$ (6,709)	$ (22,867)	$ (19,362)