Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	$ 834,832	$ 717,043
Gross Unrealized Gains	141	411
Gross Unrealized Losses	(175)	(120)
Debt Securities, Available-for-sale	834,798	717,334
Cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	90,110	137,783
Debt Securities, Available-for-sale	90,110	137,783
Cash equivalents [Member] \| Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	52,425	40,027
Debt Securities, Available-for-sale	52,425	40,027
Cash equivalents [Member] \| Time deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	37,685	36,756
Debt Securities, Available-for-sale	37,685	36,756
Cash equivalents [Member] \| Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost		61,000
Debt Securities, Available-for-sale		61,000
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	638,416	442,277
Gross Unrealized Gains	139	259
Gross Unrealized Losses	(67)	(63)
Debt Securities, Available-for-sale	638,488	442,473
Short-term investments [Member] \| Time deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	32,163	28,302
Debt Securities, Available-for-sale	32,163	28,302
Short-term investments [Member] \| Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	354,800	264,000
Gross Unrealized Gains	27	12
Gross Unrealized Losses	(13)	(19)
Debt Securities, Available-for-sale	354,814	263,993
Short-term investments [Member] \| Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	251,453	149,975
Gross Unrealized Gains	112	247
Gross Unrealized Losses	(54)	(44)
Debt Securities, Available-for-sale	251,511	150,178
Long-term investments [Member] \| Government and corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	106,306	136,983
Gross Unrealized Gains	2	152
Gross Unrealized Losses	(108)	(57)
Debt Securities, Available-for-sale	$ 106,200	$ 137,078

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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