Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating expenses:
Research and development	$ 2,580	$ 10,842	$ 12,384	$ 22,628
General and administrative	4,654	5,478	10,027	10,182
Total operating expenses	7,234	16,320	22,411	32,810
Loss from operations	(7,234)	(16,320)	(22,411)	(32,810)
Other income (expense):
Interest expense	(48)	(121)	(114)	(1,969)
Interest income	149	5	158	6
Loss on conversion of convertible notes	0	0	0	(711)
Other expense	0	(11)	0	(11)
Other income	43	0	46	0
Net loss and comprehensive loss	$ (7,090)	$ (16,447)	$ (22,321)	$ (35,495)
Net loss per share, basic	$ (0.16)	$ (0.38)	$ (0.52)	$ (0.94)
Net loss per share, diluted	$ (0.16)	$ (0.38)	$ (0.52)	$ (0.94)
Weighted average common shares outstanding, basic	43,230,523	43,041,856	43,221,712	37,564,936
Weighted average common shares outstanding, diluted	43,230,523	43,041,856	43,221,712	37,564,936