CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue				$ 165
Operating expenses:
Research and development	$ 17,182	$ 5,655	$ 32,906	9,561
General and administrative	6,718	2,823	12,987	7,800
Total operating expenses	23,900	8,478	45,893	17,361
Loss from operations	(23,900)	(8,478)	(45,893)	(17,196)
Total other income, net:
Interest income	112	781	735	1,400
Other income, net	174	427	573	700
Net loss	$ (23,614)	$ (7,270)	$ (44,585)	$ (15,096)
Net loss per share — basic and diluted	$ (0.58)	$ (4.97)	$ (2.93)	$ (13.67)
Weighted-average common shares outstanding — basic and diluted	40,465,705	1,463,421	15,195,000	1,104,454
Comprehensive loss:
Net loss	$ (23,614)	$ (7,270)	$ (44,585)	$ (15,096)
Other comprehensive (loss) income, net of tax:
Unrealized (loss) gain on available-for-sale securities	(125)	(27)	(83)	102
Unrealized (loss) gain on foreign currency translation	(26)		(26)
Total other comprehensive (loss) income	(151)	(27)	(109)	102
Comprehensive loss	$ (23,765)	$ (7,297)	$ (44,694)	$ (14,994)