Leases - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) contract	Dec. 31, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Additional right-of-use assets recorded	$ 3,389	$ 0
Right-of-use assets	$ 2,790	$ 554
Weighted average discount rate	2.50%	3.75%
Weighted average remaining lease term	3 years 10 months 24 days	1 year 1 month 6 days
Menlo Park, California, U.S. and Sawston, UK
Lessee, Lease, Description [Line Items]
Additional right-of-use assets recorded	$ 2,359
Number of leases | contract	2
Oxfordshire, UK
Lessee, Lease, Description [Line Items]
Additional right-of-use assets recorded	$ 1,030
Number of leases | contract	1