Condensed Consolidated Statements of Shareholders’ Equity - USD ($) $ in Thousands	Total	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE (LOSS)/ INCOME	ACCUMULATED DEFICIT	Ordinary shares COMMON STOCK	Deferred shares COMMON STOCK
Beginning balance (in shares) at Dec. 31, 2022					42,631,794	1
Beginning balance at Dec. 31, 2022	$ 181,280	$ 458,825	$ (16,867)	$ (261,146)	$ 440	$ 28
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)					3,790
Exercise of share options	0
Issuance of ordinary shares under ATM offering, net of issuance costs (in shares)					113,420
Issuance of ordinary shares under ATM facility, net of issuance costs	1,188	1,187			$ 1
Issuance of ordinary shares to settle vested restricted stock units (in shares)					30,481
Issuance of ordinary shares to settle vested restricted stock units	0	(1)			$ 1
Shares tendered for withholding taxes	(109)	(109)
Share-based compensation expense	4,071	4,071
Unrealized (loss) gain on foreign currency translation	(578)		(578)
Net loss	(24,208)			(24,208)
Ending balance (in shares) at Mar. 31, 2023					42,779,485	1
Ending balance at Mar. 31, 2023	161,644	463,973	(17,445)	(285,354)	$ 442	$ 28
Beginning balance (in shares) at Dec. 31, 2022					42,631,794	1
Beginning balance at Dec. 31, 2022	181,280	458,825	(16,867)	(261,146)	$ 440	$ 28
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(52,543)
Ending balance (in shares) at Jun. 30, 2023					45,760,250	0
Ending balance at Jun. 30, 2023	166,396	496,342	(16,728)	(313,689)	$ 471	$ 0
Beginning balance (in shares) at Mar. 31, 2023					42,779,485	1
Beginning balance at Mar. 31, 2023	161,644	463,973	(17,445)	(285,354)	$ 442	$ 28
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)					125,079
Exercise of share options	1				$ 1
Issuance of ordinary shares under ATM offering, net of issuance costs (in shares)					2,824,202
Issuance of ordinary shares under ATM facility, net of issuance costs	26,932	26,904			$ 28
Issuance of ordinary shares under employee share purchase plan (in shares)					23,843
Issuance of ordinary shares under employee share purchase plan	189	189
Cancellation of deferred share (in shares)						(1)
Cancellation of deferred share	0	28				$ (28)
Issuance of warrants to purchase ordinary shares	687	687
Issuance of ordinary shares to settle vested restricted stock units (in shares)					7,641
Issuance of ordinary shares to settle vested restricted stock units	0
Share-based compensation expense	4,561	4,561
Unrealized (loss) gain on foreign currency translation	717		717
Net loss	(28,335)			(28,335)
Ending balance (in shares) at Jun. 30, 2023					45,760,250	0
Ending balance at Jun. 30, 2023	$ 166,396	496,342	(16,728)	(313,689)	$ 471	$ 0
Beginning balance (in shares) at Dec. 31, 2023	61,943,471				61,943,471	0
Beginning balance at Dec. 31, 2023	$ 225,744	621,645	(16,926)	(379,610)	$ 635	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)					86,510
Exercise of share options	220	219			$ 1
Issuance of ordinary shares under ATM offering, net of issuance costs (in shares)					2,509,798
Issuance of ordinary shares under ATM facility, net of issuance costs	26,219	26,194			$ 25
Issuance of ordinary shares to settle vested restricted stock units (in shares)					50,705
Issuance of ordinary shares to settle vested restricted stock units	0
Issuance of ordinary shares to settle warrants exercised (in shares)					3,752,050
Issuance of ordinary shares to settle warrants exercised	37,258	37,220			$ 38
Shares tendered for withholding taxes	(185)	(185)
Share-based compensation expense	5,129	5,129
Unrealized (loss) gain on foreign currency translation	(36)		(36)
Net loss	(35,187)			(35,187)
Ending balance (in shares) at Mar. 31, 2024					68,342,534	0
Ending balance at Mar. 31, 2024	$ 259,162	690,222	(16,962)	(414,797)	$ 699	$ 0
Beginning balance (in shares) at Dec. 31, 2023	61,943,471				61,943,471	0
Beginning balance at Dec. 31, 2023	$ 225,744	621,645	(16,926)	(379,610)	$ 635	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (73,288)
Ending balance (in shares) at Jun. 30, 2024	68,387,469				68,387,469	0
Ending balance at Jun. 30, 2024	$ 226,273	695,353	(16,881)	(452,898)	$ 699	$ 0
Beginning balance (in shares) at Mar. 31, 2024					68,342,534	0
Beginning balance at Mar. 31, 2024	259,162	690,222	(16,962)	(414,797)	$ 699	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of share options (in shares)					3,845
Exercise of share options	0
Issuance of ordinary shares to settle vested restricted stock units (in shares)					4,438
Issuance of ordinary shares to settle vested restricted stock units	0
Vesting of equity awards under the employee purchase plan (in shares)					36,652
Issuance of ordinary shares under employee share purchase plan	210	210
Share-based compensation expense	4,921	4,921
Unrealized (loss) gain on foreign currency translation	81		81
Net loss	$ (38,101)			(38,101)
Ending balance (in shares) at Jun. 30, 2024	68,387,469				68,387,469	0
Ending balance at Jun. 30, 2024	$ 226,273	$ 695,353	$ (16,881)	$ (452,898)	$ 699	$ 0