Income Taxes - Schedule of Components of Income Tax Income (Loss) Before Provision (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
United Kingdom	$ (156,711)	$ (120,320)
Foreign	3,183	2,636
Loss before income taxes	$ (153,528)	$ (117,684)

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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+ Details