Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Financial assets and liabilities subject to fair value measurements (excluding restricted cash and cash equivalents (VIE))

The following table sets forth the Company’s financial assets and liabilities (excluding VIE cash and cash equivalents) subject to fair value measurements:

	Fair Value Measurements as of December 31, 2018
				Fair Value Hierarchy
	Total			Level 1		Level 2			Level 3
	(in thousands)
Financial instruments carried at fair value (asset position):
Cash equivalents:
Money market funds	$	1,226,603		$	1,226,603	$	—		$	—
U.S. Treasury securities	5,966			5,966		—			—
Government-sponsored enterprise securities	7,123			7,123		—			—
Commercial paper	58,268			—		58,268			—
Marketable securities:
Corporate equity securities	167,323			153,733		13,590			—
U.S. Treasury securities	6,026			6,026		—			—
Government-sponsored enterprise securities	10,704			10,704		—			—
Corporate debt securities	233,665			—		233,665			—
Commercial paper	100,390			—		100,390			—
Prepaid and other current assets:
Foreign currency forward contracts	19,023			—		19,023			—
Other assets:
Foreign currency forward contracts	1,514			—		1,514			—
Total financial assets	$	1,836,605		$	1,410,155	$	426,450		$	—
Financial instruments carried at fair value (liability position):
Other liabilities, current portion:
Foreign currency forward contracts	$	(340	)	$	—	$	(340	)	$	—
Other liabilities, excluding current portion:
Foreign currency forward contracts	(108		)	—		(108		)	—
Total financial liabilities	$	(448	)	$	—	$	(448	)	$	—

	Fair Value Measurements as of December 31, 2017
				Fair Value Hierarchy
	Total			Level 1		Level 2			Level 3
	(in thousands)
Financial instruments carried at fair value (asset position):
Cash equivalents:
Money market funds	$	614,951		$	614,951	$	—		$	—
Government-sponsored enterprise securities	12,678			12,678		—			—
Commercial paper	57,357			—		57,357			—
Marketable securities:
Corporate equity securities	74,821			74,821		—			—
Government-sponsored enterprise securities	2,303			2,303		—			—
Corporate debt securities	265,867			—		265,867			—
Commercial paper	80,263			—		80,263			—
Prepaid and other current assets:
Foreign currency forward contracts	13			—		13			—
Total financial assets	$	1,108,253		$	704,753	$	403,500		$	—
Financial instruments carried at fair value (liability position):
Other liabilities, current portion:
Foreign currency forward contracts	$	(13,642	)	$	—	$	(13,642	)	$	—
Other liabilities, excluding current portion:
Foreign currency forward contracts	(866		)	—		(866		)	—
Total financial liabilities	$	(14,508	)	$	—	$	(14,508	)	$	—