Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of financial assets measured at fair value on a recurring basis

The following tables provide the financial assets measured at fair value on a recurring basis:

	Amortized Cost or Carrying Value		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value Hierarchy as of March 31, 2020						Aggregate Fair Value
							Level 1		Level 2		Level 3
Financial Assets:	(In thousands)
Cash and cash equivalents:
Money market funds	$	275,948	$	—	$	—	$	275,948	$	—	$	—	$	275,948
Total included in cash and cash equivalents	275,948		—		—		275,948		—		—		275,948
Marketable securities:
U.S. Treasury securities	193,234		1,927		—		195,161		—		—		195,161
Corporate debt securities and commercial paper	1,311,047		2,556		(10,895)		11,000		1,291,708		—		1,302,708
Total marketable securities	1,504,281		4,483		(10,895)		206,161		1,291,708		—		1,497,869
Strategic investments	5,750		1,944		—		—		—		7,694		7,694
Total financial assets	$	1,785,979	$	6,427	$	(10,895)	$	482,109	$	1,291,708	$	7,694	$	1,781,511

	Amortized Cost or Carrying Value		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value Hierarchy as of December 31, 2019						Aggregate Fair Value
							Level 1		Level 2		Level 3
Financial Assets:	(In thousands)
Cash and cash equivalents:
Money market funds	$	153,252	$	—	$	—	$	153,252	$	—	$	—	$	153,252
Reverse repurchase agreements	35,800		—		—		—		35,800		—		35,800
Total included in cash and cash equivalents	189,052		—		—		153,252		35,800		—		189,052
Marketable securities:
U.S. Treasury securities	215,847		241		(3)		216,085		—		—		216,085
Corporate debt securities and commercial paper	1,378,487		4,516		(55)		5,000		1,377,948		—		1,382,948
Total marketable securities	1,594,334		4,757		(58)		221,085		1,377,948		—		1,599,033
Strategic investments	5,500		—		—		—		—		5,500		5,500
Total financial assets	$	1,788,886	$	4,757	$	(58)	$	374,337	$	1,413,748	$	5,500	$	1,793,585

Schedule of contractual maturities of marketable securities

The following table summarizes the contractual maturities of marketable securities:

	As of March 31, 2020				As of December 31, 2019
	Amortized Cost		Aggregate Fair Value		Amortized Cost		Aggregate Fair Value
Financial Assets:	(In thousands)
Less than one year	$	787,710	$	788,246	$	859,996	$	861,181
One to three years	716,571		709,623		734,338		737,852
Total	$	1,504,281	$	1,497,869	$	1,594,334	$	1,599,033