Fair Value Measurements - Financial Assets and Liabilities Subject to Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial instruments carried at fair value (liability positions):
Long-term contingent consideration	$ (188,500)	$ (189,600)
Recurring Basis
Financial instruments carried at fair value (asset positions):
Derivative asset current, foreign currency forward contracts	34,300	0
Derivative asset noncurrent, foreign currency forward contracts	4,781	0
Total financial assets	4,335,030	3,811,763
Financial instruments carried at fair value (liability positions):
Derivative liability current, foreign currency forward contracts	(4,356)	(59,184)
Long-term contingent consideration	(188,500)	(189,600)
Derivative liability noncurrent, foreign currency forward contracts	(29)	(4,283)
Total financial liabilities	(192,885)	(253,067)
Recurring Basis \| Level 1
Financial instruments carried at fair value (asset positions):
Derivative asset current, foreign currency forward contracts	0	0
Derivative asset noncurrent, foreign currency forward contracts	0	0
Total financial assets	3,913,069	3,236,766
Financial instruments carried at fair value (liability positions):
Derivative liability current, foreign currency forward contracts	0	0
Long-term contingent consideration	0	0
Derivative liability noncurrent, foreign currency forward contracts	0	0
Total financial liabilities	0	0
Recurring Basis \| Level 2
Financial instruments carried at fair value (asset positions):
Derivative asset current, foreign currency forward contracts	34,300	0
Derivative asset noncurrent, foreign currency forward contracts	4,781	0
Total financial assets	421,961	574,997
Financial instruments carried at fair value (liability positions):
Derivative liability current, foreign currency forward contracts	(4,356)	(59,184)
Long-term contingent consideration	0	0
Derivative liability noncurrent, foreign currency forward contracts	(29)	(4,283)
Total financial liabilities	(4,385)	(63,467)
Recurring Basis \| Level 3
Financial instruments carried at fair value (asset positions):
Derivative asset current, foreign currency forward contracts	0	0
Derivative asset noncurrent, foreign currency forward contracts	0	0
Total financial assets	0	0
Financial instruments carried at fair value (liability positions):
Derivative liability current, foreign currency forward contracts	0	0
Long-term contingent consideration	(188,500)	(189,600)
Derivative liability noncurrent, foreign currency forward contracts	0	0
Total financial liabilities	(188,500)	(189,600)
Recurring Basis \| Money market funds
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	3,578,764	3,141,053
Recurring Basis \| Money market funds \| Level 1
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	3,578,764	3,141,053
Recurring Basis \| Money market funds \| Level 2
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	0	0
Recurring Basis \| Money market funds \| Level 3
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	0	0
Recurring Basis \| Commercial paper
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	31,998	0
Marketable securities	255,523	163,268
Recurring Basis \| Commercial paper \| Level 1
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	0	0
Marketable securities	0	0
Recurring Basis \| Commercial paper \| Level 2
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	31,998	0
Marketable securities	255,523	163,268
Recurring Basis \| Commercial paper \| Level 3
Financial instruments carried at fair value (asset positions):
Cash and cash equivalents	0	0
Marketable securities	0	0
Recurring Basis \| Corporate equity securities
Financial instruments carried at fair value (asset positions):
Marketable securities	218,764	195,781
Recurring Basis \| Corporate equity securities \| Level 1
Financial instruments carried at fair value (asset positions):
Marketable securities	218,764	15,650
Recurring Basis \| Corporate equity securities \| Level 2
Financial instruments carried at fair value (asset positions):
Marketable securities	0	180,131
Recurring Basis \| Corporate equity securities \| Level 3
Financial instruments carried at fair value (asset positions):
Marketable securities	0	0
Recurring Basis \| U.S. Treasury securities
Financial instruments carried at fair value (asset positions):
Marketable securities	46,539	0
Recurring Basis \| U.S. Treasury securities \| Level 1
Financial instruments carried at fair value (asset positions):
Marketable securities	46,539	0
Recurring Basis \| U.S. Treasury securities \| Level 2
Financial instruments carried at fair value (asset positions):
Marketable securities	0	0
Recurring Basis \| U.S. Treasury securities \| Level 3
Financial instruments carried at fair value (asset positions):
Marketable securities	0	0
Recurring Basis \| Government-sponsored enterprise securities
Financial instruments carried at fair value (asset positions):
Marketable securities	69,002	80,063
Recurring Basis \| Government-sponsored enterprise securities \| Level 1
Financial instruments carried at fair value (asset positions):
Marketable securities	69,002	80,063
Recurring Basis \| Government-sponsored enterprise securities \| Level 2
Financial instruments carried at fair value (asset positions):
Marketable securities	0	0
Recurring Basis \| Government-sponsored enterprise securities \| Level 3
Financial instruments carried at fair value (asset positions):
Marketable securities	0	0
Recurring Basis \| Corporate debt securities
Financial instruments carried at fair value (asset positions):
Marketable securities	95,359	231,598
Recurring Basis \| Corporate debt securities \| Level 1
Financial instruments carried at fair value (asset positions):
Marketable securities	0	0
Recurring Basis \| Corporate debt securities \| Level 2
Financial instruments carried at fair value (asset positions):
Marketable securities	95,359	231,598
Recurring Basis \| Corporate debt securities \| Level 3
Financial instruments carried at fair value (asset positions):
Marketable securities	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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