Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2016

Fair Value Disclosures [Abstract]

Schedule of Marketable Securities

The following is a summary of available-for-sale marketable securities held as of September 30, 2016 and December 31, 2015 (in thousands):

			Gross Unrealized							Classification on Balance Sheet
	Amortized Cost		Gains		Losses			Aggregate Fair Value		Short-Term Marketable Securities		Long-Term Marketable Securities
As of September 30, 2016
Commercial paper	$	37,307	$	26	$	(59	)	$	37,274	$	37,274	$	—
Corporate bonds	970,750		791		(805		)	970,736		426,218		544,518
U.S. government agency obligations	285,422		162		(76		)	285,508		65,552		219,956
	$	1,293,479	$	979	$	(940	)	$	1,293,518	$	529,044	$	764,474
As of December 31, 2015
Commercial paper	$	2,491	$	—	$	(4	)	$	2,487	$	2,487	$	—
Corporate bonds	995,100		73		(3,365		)	991,808		432,585		559,223
U.S. government agency obligations	239,587		41		(575		)	239,053		25,016		214,037
	$	1,237,178	$	114	$	(3,944	)	$	1,233,348	$	460,088	$	773,260

Schedule of Fair Value Measurement

The following table details the fair value measurements within the fair value hierarchy of the Company’s financial assets at September 30, 2016 and December 31, 2015 (in thousands):

	Total Fair Value		Fair Value Measurements at Reporting Date Using
			Level 1		Level 2		Level 3
As of September 30, 2016
Cash Equivalents and Marketable Securities:
Money market funds	$	5,205	$	5,205	$	—	$	—
Commercial paper	37,274		—		37,274		—
Corporate bonds	970,736		—		970,736		—
U.S. government agency obligations	285,508		—		285,508		—
Mutual funds	3,589		3,589		—		—
	$	1,302,312	$	8,794	$	1,293,518	$	—
As of December 31, 2015
Cash Equivalents and Marketable Securities:
Money market funds	$	1,250	$	1,250	$	—	$	—
Commercial paper	2,487		—		2,487		—
Corporate bonds	991,808		—		991,808		—
U.S. government agency obligations	239,053		—		239,053		—
Mutual funds	1,414		1,414		—		—
	$	1,236,012	$	2,664	$	1,233,348	$	—

Schedule of Contractual Maturities of Marketable Securities and Other Investment Related Assets

Contractual maturities of the Company’s available-for-sale marketable securities held as of September 30, 2016 and December 31, 2015 were as follows (in thousands):

	September 30, 2016		December 31, 2015
Due in 1 year or less	$	529,044	$	460,088
Due after 1 year through 5 years	764,474		773,260
	$	1,293,518	$	1,233,348