Condensed Consolidated 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 expenses	$ 6,137	$ 3,902	$ 11,962	$ 8,253
General and administrative expenses	2,394	2,093	4,812	3,862
Total operating expenses	8,531	5,995	16,774	12,115
Loss from operations	(8,531)	(5,995)	(16,774)	(12,115)
Other income and expenses:
Grant income	1,081	678	2,670	1,442
Fair value adjustment for preferred stock tranche rights liability and anti-dilution warrants liability		(488)	1,265	296
R&D tax credits	186	155	370	353
Other income (expense), net	12	(47)	(30)	(75)
Loss before income taxes	(7,252)	(5,697)	(12,499)	(10,099)
Income tax benefit (expense)	50	(58)	50	(58)
Net loss	(7,202)	(5,755)	(12,449)	(10,157)
Cumulative dividends on Series A preferred stock	(106)	(106)	(213)	(213)
Accretion of redeemable convertible preferred stock to redemption value			(4,189)	(1,612)
Net loss attributable to common stockholders	$ (10,302)	$ (6,776)	$ (16,851)	$ (11,982)
Basic and diluted net loss per common share	$ (29.49)	$ (36.49)	$ (55.63)	$ (64.52)
Weighted-average common shares outstanding—basic and diluted	349,290	185,716	302,919	185,716
Net loss	$ (7,202)	$ (5,755)	$ (12,449)	$ (10,157)
Foreign currency translation adjustments	245	529	(72)	262
Comprehensive loss	(6,957)	(5,226)	(12,521)	(9,895)
Series A Preferred Stock
Other income and expenses:
Accretion of redeemable convertible preferred stock to redemption value	$ (2,994)	$ (915)	$ (4,189)	$ (1,612)