Income Taxes (Tables)

12 Months Ended

Dec. 31, 2024

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

Income (loss) before provision for income taxes consisted of the following (in thousands):

	Year Ended December 31,
	2024	2023
United Kingdom	(156,711)	(120,320)
Foreign	3,183	2,636
Loss before provision for income taxes	(153,528)	(117,684)

Schedule of Components of Income Tax Expense (Benefit)

The income tax provision for the years then ended comprised (in thousands):

	Year Ended December 31,
	2024		2023
Current income tax provision
United Kingdom	$	—	$	—
Foreign	2,031		1,893
Total current expense:	$	2,031	$	1,893
Deferred income tax benefit:
United Kingdom	—		—
Foreign	(437)		(1,113)
Total deferred income tax benefit:	$	(437)	$	(1,113)
Total provision for income taxes	$	1,594	$	780

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of income tax expense computed at the statutory UK corporation tax rate to income taxes as reflected in the consolidated financial statements is as follows (in thousands):

	Year Ended December 31,
	2024		2023
Corporation tax at UK statutory rate	$	(38,382)	$	(27,656)
Permanent differences	27		1
UK R&D tax credit	14,375		10,720
Change in valuation allowance	25,410		20,971
State income taxes	57		23
Deferred tax asset true-up	676		187
Return to provision	(1,214)		(2,259)
Share-based compensation	774		33
Change in UK tax rate	—		(1,258)
Other	(129)		18
	$	1,594	$	780

Schedule of Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2024 and 2023 consist of the following (in thousands):

	Year Ended December 31,
	2024		2023
Net operating loss carryforward	$	84,927	$	64,747
Reserves and accruals	647		564
Share-based compensation	18,205		14,159
Charitable contributions	126		36
Total deferred tax assets	103,905		79,506
Valuation allowance	$	(100,090)	$	(76,072)
Depreciation	(41)		(98)
Total deferred tax liabilities	(41)		(98)
Net deferred tax assets	$	3,774	$	3,336

Summary of Valuation Allowance

Changes in the valuation allowance for deferred tax assets during the years ended December 31, 2024 and 2023 related primarily to the increases in net operating loss and were as follows (in thousands):

	Year Ended December 31,
	2024		2023
Valuation allowance at beginning of year	$	76,072	$	51,909
Increases recorded to income tax provision	25,411		20,971
Increases recorded to CTA	(1,393)		3,192
Valuation allowance at end of year	$	100,090	$	76,072