Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Research and development (including related party expenses of $98 and $(217) for the three months ended June 30, 2020 and 2019, respectively, and $315 and $112 for the six months ended June 30, 2020 and 2019, respectively)	$ 18,178	$ 9,968	$ 42,493	$ 22,595
General and administrative	3,046	2,264	6,327	3,580
Total operating expenses	21,224	12,232	48,820	26,175
Loss from operations	(21,224)	(12,232)	(48,820)	(26,175)
Other income (expense), net:
Interest expense		(11)	(7)	(24)
Interest income	44	181	179	418
Grant income	1,036		1,365
Foreign currency transaction losses	(176)	(53)	(179)	(231)
Change in fair value of the redeemable convertible preferred stock tranche liability		1,450		1,676
Total other income (expense), net	904	1,567	1,358	1,839
Net loss and comprehensive loss	$ (20,320)	$ (10,665)	$ (47,462)	$ (24,336)
Net loss per share, basic and diluted	$ (1.72)	$ (2.90)	$ (5.99)	$ (6.62)
Weighted-average shares outstanding, basic and diluted	11,803,778	3,682,897	7,926,818	3,677,032