Fair Value Measurements - Marketable Securities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Amortized Cost	$ 916,217	$ 1,610,775
Gross Unrealized Gains	0	1,194
Gross Unrealized Losses	(30,515)	(5,580)
Aggregate Fair Value	885,702	1,606,389
Short-Term Marketable Securities	263,369	540,574
Long-Term Marketable Securities	622,333	1,065,815
Commercial paper
Marketable Securities [Line Items]
Amortized Cost		25,056
Gross Unrealized Gains		0
Gross Unrealized Losses		(24)
Aggregate Fair Value		25,032
Short-Term Marketable Securities		25,032
Long-Term Marketable Securities		0
Corporate bonds
Marketable Securities [Line Items]
Amortized Cost	644,104	1,268,991
Gross Unrealized Gains	0	1,191
Gross Unrealized Losses	(21,749)	(4,275)
Aggregate Fair Value	622,355	1,265,907
Short-Term Marketable Securities	239,659	459,012
Long-Term Marketable Securities	382,696	806,895
Available-for-sale marketable securities, continuous unrealized loss position for more than 12 months	137,900
Unrealized loss related to corporate bonds	4,200
U.S. government agency obligations
Marketable Securities [Line Items]
Amortized Cost	272,113	316,728
Gross Unrealized Gains	0	3
Gross Unrealized Losses	(8,766)	(1,281)
Aggregate Fair Value	263,347	315,450
Short-Term Marketable Securities	23,710	56,530
Long-Term Marketable Securities	$ 239,637	$ 258,920