Condensed 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, 2018	$ 41,820	$ 54,621	$ 25,756
Beginning balance (in shares) at Dec. 31, 2018	2,800,001	3,947,198	1,323,248
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares			$ 1,583
Issuance of convertible preferred shares (in shares)			80,385
Ending balance at Mar. 31, 2019	$ 41,820	$ 54,621	$ 27,339
Ending balance (in shares) at Mar. 31, 2019	2,800,001	3,947,198	1,403,633
Beginning balance at Dec. 31, 2018				$ 10	$ 1,857	$ (1,751)	$ (69,942)	$ (69,826)
Beginning balance (in shares) at Dec. 31, 2018				814,728
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards				$ 1	103			104
Issuance of restricted share awards (in shares)				27,304
Issuance of ordinary shares upon exercise of share options (in shares)				3
Share based compensation expense					172			172
Foreign currency translation adjustment						1,080		1,080
Net loss							(6,503)	(6,503)
Ending balance at Mar. 31, 2019				$ 11	2,132	(671)	(76,445)	(74,973)
Ending balance (in shares) at Mar. 31, 2019				842,035
Beginning balance at Dec. 31, 2018	$ 41,820	$ 54,621	$ 25,756
Beginning balance (in shares) at Dec. 31, 2018	2,800,001	3,947,198	1,323,248
Beginning balance at Dec. 31, 2018				$ 10	1,857	(1,751)	(69,942)	(69,826)
Beginning balance (in shares) at Dec. 31, 2018				814,728
Increase (decrease) in shareholders' equity (deficit)
Foreign currency translation adjustment								(432)
Net loss								(16,720)
Ending balance at Jun. 30, 2019				$ 226	193,178	(2,183)	(86,662)	104,559
Ending balance (in shares) at Jun. 30, 2019				17,900,731
Beginning balance at Mar. 31, 2019	$ 41,820	$ 54,621	$ 27,339
Beginning balance (in shares) at Mar. 31, 2019	2,800,001	3,947,198	1,403,633
Increase (decrease) in convertible preferred shares
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)
Beginning balance at Mar. 31, 2019				$ 11	2,132	(671)	(76,445)	(74,973)
Beginning balance (in shares) at Mar. 31, 2019				842,035
Increase (decrease) in shareholders' equity (deficit)
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
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)				702,557
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses of $8.4 million				$ 59	56,469			56,528
Number of shares issued (in shares)				4,637,666
Issuance of restricted share awards				$ 1	292			293
Issuance of restricted share awards (in shares)				56,643
Issuance of ordinary shares upon exercise of share options					21			21
Issuance of ordinary shares upon exercise of share options (in shares)				14,301
Share based compensation expense					612			612
Foreign currency translation adjustment						(1,512)		(1,512)
Net loss							(10,217)	(10,217)
Ending balance at Jun. 30, 2019				$ 226	193,178	(2,183)	(86,662)	104,559
Ending balance (in shares) at Jun. 30, 2019				17,900,731
Beginning balance at Dec. 31, 2019				$ 227	195,056	(1,535)	(100,550)	$ 93,198
Beginning 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 share options					2			$ 2
Issuance of ordinary shares upon exercise of share options (in shares)				1,071
Issuance of ordinary shares upon exercise of warrants (in shares)				21,435
Share based compensation expense					2,121			2,121
Foreign currency translation adjustment						(2,184)		(2,184)
Net loss							(11,324)	(11,324)
Ending balance at Mar. 31, 2020				$ 227	197,179	(3,719)	(111,874)	81,813
Ending balance (in shares) at Mar. 31, 2020				18,016,207
Beginning balance at Dec. 31, 2019				$ 227	195,056	(1,535)	(100,550)	$ 93,198
Beginning balance (in shares) at Dec. 31, 2019				17,993,701				17,993,701
Increase (decrease) in shareholders' equity (deficit)
Foreign currency translation adjustment								$ (2,185)
Net loss								(23,438)
Ending balance at Jun. 30, 2020				$ 228	198,507	(3,720)	(123,989)	$ 71,026
Ending balance (in shares) at Jun. 30, 2020				18,091,657				18,091,657
Beginning balance at Mar. 31, 2020				$ 227	197,179	(3,719)	(111,874)	$ 81,813
Beginning balance (in shares) at Mar. 31, 2020				18,016,207
Increase (decrease) in shareholders' equity (deficit)
Issuance of ordinary shares upon exercise of share options					9			9
Issuance of ordinary shares upon exercise of share options (in shares)				4,000
Issuance of ordinary shares upon exercise of warrants				$ 1				1
Issuance of ordinary shares upon exercise of warrants (in shares)				71,450
Share based compensation expense					1,319			1,319
Foreign currency translation adjustment						(1)		(1)
Net loss							(12,115)	(12,115)
Ending balance at Jun. 30, 2020				$ 228	$ 198,507	$ (3,720)	$ (123,989)	$ 71,026
Ending balance (in shares) at Jun. 30, 2020				18,091,657				18,091,657