Consolidated Statements of Convertible Preferred Shares and Shareholders’ Equity (Deficit) - USD ($) $ in Thousands	Series A Convertible Preferred Shares	Series B1 Convertible Preferred Shares	Series B2 Convertible Preferred Shares	Ordinary Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Beginning balance at Dec. 31, 2017	$ 41,820	$ 54,621
Beginning balance (in shares) at Dec. 31, 2017	2,800,001	3,947,198
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares			$ 25,756
Issuance of convertible preferred shares (in shares)			1,323,248
Ending balance at Dec. 31, 2018	$ 41,820	$ 54,621	$ 25,756
Ending balance (in shares) at Dec. 31, 2018	2,800,001	3,947,198	1,323,248
Beginning balance at Dec. 31, 2017				$ 5	$ 838	$ 69	$ (48,096)	$ (47,184)
Beginning balance (in shares) at Dec. 31, 2017				368,995
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards				$ 1	223			224
Issuance of restricted share awards (in shares)				95,644
Issuance of ordinary shares in exchange for surrender of vested share options				$ 4	(4)
Issuance of ordinary shares in exchange for surrender of vested share options (in shares)				340,728
Issuance of ordinary shares upon exercise of share options (in shares)				9,361
Share based compensation expense					800			800
Foreign currency translation adjustment						(1,820)		(1,820)
Net loss							(21,846)	(21,846)
Ending balance at Dec. 31, 2018				$ 10	1,857	(1,751)	(69,942)	(69,826)
Ending balance (in shares) at Dec. 31, 2018				814,728
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares			$ 1,583
Issuance of convertible preferred shares (in shares)			80,385
Conversion of convertible preferred shares to ordinary shares	$ (41,820)	$ (54,621)	$ (27,339)
Conversion of convertible preferred shares to ordinary shares (in shares)	(2,800,001)	(3,947,198)	(1,403,633)
Increase (decrease) in shareholders' equity (deficit)
Reclassification of warrant liability to additional paid-in capital and exercise of warrants				$ 9	10,018			10,027
Reclassification of warrant liability to additional paid-in capital and exercise of warrants (in shares)				723,992
Conversion of convertible preferred shares to ordinary shares				$ 146	123,634			123,780
Conversion of convertible preferred shares to ordinary shares (in shares)				11,647,529
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses				$ 59	56,322			56,381
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses (in shares)				4,637,666
Issuance of restricted share awards				$ 2	395			397
Issuance of restricted share awards (in shares)				83,947
Issuance of ordinary shares upon exercise of share options				$ 1	142			143
Issuance of ordinary shares upon exercise of share options (in shares)				85,839
Share based compensation expense					2,688			2,688
Foreign currency translation adjustment						216		216
Net loss							(30,608)	(30,608)
Ending balance at Dec. 31, 2019				$ 227	195,056	(1,535)	(100,550)	$ 93,198
Ending balance (in shares) at Dec. 31, 2019				17,993,701				17,993,701
Increase (decrease) in shareholders' equity (deficit)
Issuance of ordinary shares upon exercise of warrants				$ 1				$ 1
Issuance of ordinary shares upon exercise of warrants (in shares)				92,885
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses				$ 37	48,107			48,144
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses (in shares)				2,928,813
Issuance of ordinary shares upon exercise of share options				$ 1	270			271
Issuance of ordinary shares upon exercise of share options (in shares)				79,158
Share based compensation expense					6,514			6,514
Foreign currency translation adjustment						(1,658)		(1,658)
Net loss							(51,010)	(51,010)
Ending balance at Dec. 31, 2020				$ 266	$ 249,947	$ (3,193)	$ (151,560)	$ 95,460
Ending balance (in shares) at Dec. 31, 2020				21,094,557				21,094,557