Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating expenses:
Research and development	$ 14,149	$ 10,189	$ 28,102	$ 21,780
General and administrative	6,424	6,260	12,289	10,804
Total operating expenses	20,573	16,449	40,391	32,584
Loss from operations	(20,573)	(16,449)	(40,391)	(32,584)
Other expense (income), net:
Changes in fair value of warrant liabilities				16,240
Other expense (income), net	48	24	77	(517)
Total other expense (income), net	48	24	77	15,723
Loss before provision for (benefit from) income taxes, net	(20,621)	(16,473)	(40,468)	(48,307)
Provision for (benefit from) income taxes, net	9	(11)	77	67
Net loss and comprehensive loss	$ (20,630)	$ (16,462)	$ (40,545)	$ (48,374)
Net loss per common share, basic and diluted	$ (1.67)	$ (1.58)	$ (3.38)	$ (4.71)
Weighted-average shares used in computing net loss per common share, basic and diluted	12,350,660	10,395,732	12,011,199	10,276,180