Unaudited Condensed Consolidated Statements of Operations and Comprehensive Loss - 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	$ 2,309	$ 11,368	$ 8,989	$ 22,225
General and administrative	3,412	3,992	8,894	7,688
Restructuring charges	44		902
Gain from lease termination and asset sale			(508)
Total operating expenses	5,765	15,360	18,277	29,913
Loss from operations	(5,765)	(15,360)	(18,277)	(29,913)
Other income (expense):
Interest income	67	27	90	63
Interest expense	(511)	(247)	(925)	(491)
Other expense, net	(53)	(5)	(30)	(12)
Total other income (expense)	(497)	(225)	(865)	(440)
Net loss	(6,262)	(15,585)	(19,142)	(30,353)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities, net	23	8	(15)	6
Comprehensive loss	$ (6,239)	$ (15,577)	$ (19,157)	$ (30,347)
Net loss per share, basic	$ (0.15)	$ (0.59)	$ (0.45)	$ (1.16)
Weighted average shares of common stock outstanding, basic	42,430,487	26,369,636	42,278,932	26,189,664
Net loss per share, diluted	$ (0.15)	$ (0.59)	$ (0.45)	$ (1.16)
Weighted average shares of common stock outstanding, diluted	42,430,487	26,369,636	42,278,932	26,189,664