Cash, cash equivalents and marketable securities - Composition of Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Cash and cash equivalents:
Amortized Cost	$ 1,361,980	$ 1,611,082
Unrealized Gains	0	2
Unrealized Losses	(44)	(21)
Fair Value	1,361,936	1,611,063
Marketable securities:
Amortized Cost	1,149,425	1,097,467
Unrealized Gains	1,896	380
Unrealized Losses	(2,173)	(10,683)
Fair Value	1,149,148	1,087,164
Total
Amortized Cost	2,511,405	2,708,549
Unrealized Gains	1,896	382
Unrealized Losses	(2,217)	(10,704)
Fair Value	2,511,084	2,698,227
Corporate bonds
Marketable securities:
Amortized Cost	428,002	370,445
Unrealized Gains	1,277	172
Unrealized Losses	(1,322)	(7,542)
Fair Value	427,957	363,075
Commercial paper
Marketable securities:
Amortized Cost	200,963	241,407
Unrealized Gains	212	71
Unrealized Losses	(30)	(286)
Fair Value	201,145	241,192
U.S. treasury securities
Marketable securities:
Amortized Cost	336,721	244,056
Unrealized Gains	251	33
Unrealized Losses	(616)	(1,173)
Fair Value	336,356	242,916
Certificates of deposit
Marketable securities:
Amortized Cost	132,314	158,607
Unrealized Gains	152	60
Unrealized Losses	(9)	(421)
Fair Value	132,457	158,246
Municipal securities
Marketable securities:
Amortized Cost		28,029
Unrealized Gains		4
Unrealized Losses		(584)
Fair Value		27,449
Non-U.S. government and supranational bonds
Marketable securities:
Amortized Cost	9,101	23,228
Unrealized Gains	1	0
Unrealized Losses	(119)	(629)
Fair Value	8,983	22,599
U.S. agency bonds
Marketable securities:
Amortized Cost	42,324	31,695
Unrealized Gains	3	40
Unrealized Losses	(77)	(48)
Fair Value	42,250	31,687
Cash
Cash and cash equivalents:
Amortized Cost	220,583	474,365
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	220,583	474,365
Money market funds
Cash and cash equivalents:
Amortized Cost	1,032,675	1,017,191
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	1,032,675	1,017,191
Commercial paper
Cash and cash equivalents:
Amortized Cost	106,312	111,996
Unrealized Gains	0	0
Unrealized Losses	(44)	(21)
Fair Value	106,268	111,975
Corporate bonds
Cash and cash equivalents:
Amortized Cost	859	1,542
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	859	1,542
U.S. treasury securities
Cash and cash equivalents:
Amortized Cost		5,988
Unrealized Gains		2
Unrealized Losses		0
Fair Value		$ 5,990
Certificates of deposit
Cash and cash equivalents:
Amortized Cost	1,551
Unrealized Gains	0
Unrealized Losses	0
Fair Value	$ 1,551