Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Ordinary Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2020	$ 178,434	$ 12,507	$ 771,194	$ 373	$ (605,640)
Balance, Shares at Dec. 31, 2020		98,283,603
Share-based compensation expense	6,268		6,268
Exercise of share options	2,822	$ 172	2,650
Exercise of share options, Shares		1,319,493
Vesting of restricted stock units, net of shares withheld for taxes	(296)	$ 6	(302)
Vesting of restricted stock units, net of shares withheld for taxes, shares		45,746
Sale of ordinary shares and non-voting ordinary shares, net of issuance costs	143,711	$ 3,310	140,401
Sale of ordinary shares and non-voting ordinary shares, net of issuance costs, Shares		24,115,755
Issuance costs associated with sale of voting and non-voting ordinary shares	(6,289)
Foreign currency translation	(64)			(64)
Unrealized loss on available for sale debt securities	(113)			(113)
Net loss attributable to ordinary shareholders	(35,182)				(35,182)
Balance at Mar. 31, 2021	295,580	$ 15,995	920,211	196	(640,822)
Balance, Shares at Mar. 31, 2021		123,764,597
Balance at Dec. 31, 2020	178,434	$ 12,507	771,194	373	(605,640)
Balance, Shares at Dec. 31, 2020		98,283,603
Foreign currency translation	(438)
Unrealized loss on available for sale debt securities	(121)
Net loss attributable to ordinary shareholders	(71,791)
Balance at Jun. 30, 2021	264,374	$ 16,010	925,981	(186)	(677,431)
Balance, Shares at Jun. 30, 2021		123,883,097
Balance at Mar. 31, 2021	295,580	$ 15,995	920,211	196	(640,822)
Balance, Shares at Mar. 31, 2021		123,764,597
Share-based compensation expense	5,541		5,541
Exercise of share options	9	$ 2	7
Exercise of share options, Shares		15,725
Issuance of ESPP shares	301	$ 13	288
Issuance of ESPP shares, Shares		102,775
Issuance costs associated with sale of voting and non-voting ordinary shares	(66)		(66)
Foreign currency translation	(374)			(374)
Unrealized loss on available for sale debt securities	(8)			(8)
Net loss attributable to ordinary shareholders	(36,609)				(36,609)
Balance at Jun. 30, 2021	264,374	$ 16,010	925,981	(186)	(677,431)
Balance, Shares at Jun. 30, 2021		123,883,097
Balance at Dec. 31, 2021	209,950	$ 16,253	940,675	3,246	(750,224)
Balance, Shares at Dec. 31, 2021		125,674,095
Share-based compensation expense	4,660		4,660
Exercise of share options	(1)	$ 28	(29)
Exercise of share options, Shares		222,381
Vesting of restricted stock units, net of shares withheld for taxes	(3)	$ 1	(4)
Vesting of restricted stock units, net of shares withheld for taxes, shares		3,217
Ordinary shares issued as part of a consulting agreement	1	$ 1
Ordinary shares issued as part of consulting agreement, Shares		5,252
Foreign currency translation	5,595			5,595
Unrealized loss on available for sale debt securities	(260)			(260)
Net loss attributable to ordinary shareholders	(44,296)				(44,296)
Balance at Mar. 31, 2022	175,646	$ 16,283	945,302	8,581	(794,520)
Balance, Shares at Mar. 31, 2022		125,904,945
Balance at Dec. 31, 2021	$ 209,950	$ 16,253	940,675	3,246	(750,224)
Balance, Shares at Dec. 31, 2021		125,674,095
Exercise of share options, Shares	397,534
Foreign currency translation	$ 23,045
Unrealized loss on available for sale debt securities	(261)
Net loss attributable to ordinary shareholders	(95,212)
Balance at Jun. 30, 2022	146,272	$ 16,353	949,325	26,030	(845,436)
Balance, Shares at Jun. 30, 2022		126,436,213
Balance at Mar. 31, 2022	175,646	$ 16,283	945,302	8,581	(794,520)
Balance, Shares at Mar. 31, 2022		125,904,945
Share-based compensation expense	3,956		3,956
Exercise of share options	1	$ 24	(23)
Exercise of share options, Shares		175,153
Issuance of ESPP shares	136	$ 46	90
Issuance of ESPP shares, Shares		356,115
Foreign currency translation	17,450			17,450
Unrealized loss on available for sale debt securities	(1)			(1)
Net loss attributable to ordinary shareholders	(50,916)				(50,916)
Balance at Jun. 30, 2022	$ 146,272	$ 16,353	$ 949,325	$ 26,030	$ (845,436)
Balance, Shares at Jun. 30, 2022		126,436,213