Collaboration Agreements - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Janssen Agreement
Contract liabilities
Deferred revenue beginning balance	$ 0
Deferred revenue, Additions	40,000
Deferred revenue, Deductions	1,735
Deferred revenue ending balance	38,265
Amounts included in the contract liability at the beginning of the period	0
Performance obligations satisfied in previous periods	0
Merck KGaA
Contract liabilities
Deferred revenue beginning balance	3,944	$ 3,987
Deferred revenue, Additions	0	0
Deferred revenue, Deductions	11	11
Deferred revenue ending balance	3,933	3,976
Amounts included in the contract liability at the beginning of the period	11	11
Performance obligations satisfied in previous periods	$ 0	$ 0