Cash, cash equivalents and marketable securities - Composition of Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Cash and cash equivalents:
Amortized Cost	$ 969,352	$ 1,136,471
Unrealized Gains	14	1
Unrealized Losses	(24)	(12)
Fair Value	969,342	1,136,460
Marketable securities:
Amortized Cost	1,494,374	1,375,512
Unrealized Gains	3,501	2,167
Unrealized Losses	(64)	(1,270)
Fair Value	1,497,811	1,376,409
Total
Amortized Cost	2,463,726	2,511,983
Unrealized Gains	3,515	2,168
Unrealized Losses	(88)	(1,282)
Fair Value	2,467,153	2,512,869
Corporate bonds
Marketable securities:
Amortized Cost	704,069	515,301
Unrealized Gains	2,277	1,385
Unrealized Losses	(58)	(474)
Fair Value	706,288	516,212
U.S. treasury securities
Marketable securities:
Amortized Cost	373,920	425,677
Unrealized Gains	929	439
Unrealized Losses	(5)	(763)
Fair Value	374,844	425,353
Commercial paper
Marketable securities:
Amortized Cost	253,304	260,205
Unrealized Gains	163	191
Unrealized Losses	(1)	(11)
Fair Value	253,466	260,385
Certificates of deposit
Marketable securities:
Amortized Cost	163,081	171,892
Unrealized Gains	132	151
Unrealized Losses	0	(22)
Fair Value	163,213	172,021
Non-U.S. government and supranational bonds
Marketable securities:
Amortized Cost		2,437
Unrealized Gains		1
Unrealized Losses		0
Fair Value		2,438
Cash
Cash and cash equivalents:
Amortized Cost	160,698	111,718
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	160,698	111,718
Money market funds
Cash and cash equivalents:
Amortized Cost	452,315	861,824
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	452,315	861,824
Commercial paper
Cash and cash equivalents:
Amortized Cost	286,897	150,464
Unrealized Gains	6	1
Unrealized Losses	(24)	(9)
Fair Value	286,879	150,456
U.S. treasury securities
Cash and cash equivalents:
Amortized Cost	64,926
Unrealized Gains	8
Unrealized Losses	0
Fair Value	64,934
Corporate bonds
Cash and cash equivalents:
Amortized Cost	4,516	8,307
Unrealized Gains	0	0
Unrealized Losses	0	(3)
Fair Value	$ 4,516	8,304
Certificates of deposit
Cash and cash equivalents:
Amortized Cost		4,158
Unrealized Gains		0
Unrealized Losses		0
Fair Value		$ 4,158