Collaboration agreements - Contract Assets and Liabilities (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Contract liabilities
Balance at Beginning of Period	$ 147,653,000	$ 3,944,000
Additions	0	40,000,000
Deductions	3,302,000	1,746,000
Balance at End of Period	144,351,000	42,198,000
Amounts included in the contract liability at the beginning of the period	5,110,000	11,000
Janssen Agreement
Contract liabilities
Balance at Beginning of Period	15,800,000
Balance at End of Period	16,200,000
Contract assets	0	0
GSK Agreement
Contract liabilities
Balance at Beginning of Period	98,000,000
Balance at End of Period	97,300,000
Contract assets	0	0
2022 Merck Research Collaboration & License Agreement
Contract liabilities
Balance at Beginning of Period	30,000,000
Balance at End of Period	26,900,000
Contract assets	0	0
2014 & 2018 Collaboration and Commercial License Agreement and Supply Agreement Merck KGaA
Contract liabilities
Balance at Beginning of Period	3,900,000
Balance at End of Period	3,900,000
Contract assets	$ 0	$ 0