Income Taxes - Schedule of Components of Income Tax Income (Loss) Before Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
United Kingdom	$ (72,397)	$ (60,522)	$ (19,619)
Foreign	854	220	22
Loss before income taxes	$ (71,543)	$ (60,302)	$ (19,597)