Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development	$ 13,953	$ 11,591
General and administrative	5,865	4,544
Total operating expenses	19,818	16,135
Loss from operations	(19,818)	(16,135)
Other income (expense), net:
Changes in fair value of warrant liabilities		(16,240)
Other income (expense), net	(29)	541
Total other income (expense), net	(29)	(15,699)
Loss before provision for income taxes, net	(19,847)	(31,834)
Provision for income taxes, net	68	78
Net loss and comprehensive loss	$ (19,915)	$ (31,912)
Net loss per common share, basic and diluted	$ (1.71)	$ (3.14)
Weighted-average shares used in computing net loss per common share, basic and diluted	11,667,967	10,156,628