Deferred royalty obligation - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Aug. 25, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Royalty Obligation [Line Items]
Royalty purchase agreement	$ 325,000
Proceeds from royalties	$ 225,000	$ 75,000		$ 225,000
Royalties, percent of worldwide sales	7.00%
Royalties, percent of milestone payments	7.00%
Royalties, percent of performance tests	10.00%
Royalties, high-single-digit percentage rate	10.00%
Royalty cap, period of payment	36 months
Royalty cap, payment percentage	200.00%
Royalty cap, termination period	27 months
Buyout percent	50.00%
Buyout, percent of payments	50.00%
Transaction costs		1,900		7,000
Proceeds from royalties, net of transaction costs		73,100		$ 218,000
Royalties, effective interest rate	10.00%
Cumulative catch-up adjustment, deferred royalty obligation		4,972	$ 15,402
Minimum
Royalty Obligation [Line Items]
Royalties, royalty cap	225.00%
Royalty obligation		675,000	506,300
Royalty cap, obligation		580,100	438,800
Maximum
Royalty Obligation [Line Items]
Royalties, royalty cap	250.00%
Royalty obligation		750,000	562,500
Royalty cap, obligation		$ 600,000	$ 450,000
ZYNLONTA
Royalty Obligation [Line Items]
Royalties, percent of worldwide sales	7.00%
Cami
Royalty Obligation [Line Items]
Royalties, percent of worldwide sales	7.00%