Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Marketable Securities

The following is a summary of available-for-sale marketable securities held as of December 31, 2017 and 2016 (in thousands):

			Gross Unrealized					Aggregate Fair Value		Classification on Balance Sheet
	Amortized Cost									Short-Term Marketable Securities		Long-Term Marketable Securities
As of December 31, 2017			Gains		Losses
Commercial paper	$	6,951	$	—	$	(9	)	$	6,942	$	6,942	$	—
Corporate bonds	736,902		2		(3,829		)	733,075		289,378		443,697
U.S. government agency obligations	220,014		—		(1,764		)	218,250		102,234		116,016
	$	963,867	$	2	$	(5,602	)	$	958,267	$	398,554	$	559,713
As of December 31, 2016
Commercial paper	$	40,965	$	—	$	(45	)	$	40,920	$	40,920	$	—
Corporate bonds	984,650		123		(3,697		)	981,076		418,495		562,581
U.S. government agency obligations	267,473		35		(1,366		)	266,142		53,157		212,985
	$	1,293,088	$	158	$	(5,108	)	$	1,288,138	$	512,572	$	775,566

Schedule of Fair Value Measurement

The following table details the fair value measurements within the fair value hierarchy of the Company’s financial assets and liabilities as of December 31, 2017 and 2016 (in thousands):

	Total Fair Value			Fair Value Measurements at Reporting Date Using
				Level 1		Level 2		Level 3
As of December 31, 2017
Cash Equivalents and Marketable Securities:
Money market funds	$	22,649		$	22,649	$	—	$	—
Commercial paper	10,928			—		10,928		—
Corporate bonds	733,075			—		733,075		—
U.S. government agency obligations	218,248			—		218,248		—
Mutual funds	7,879			7,879		—		—
	$	992,779		$	30,528	$	962,251	$	—
Liabilities:
Contingent consideration obligation related to completed acquisitions	$	(8,631	)	$	—	$	—	$	(8,631	)
As of December 31, 2016
Cash Equivalents and Marketable Securities:
Money market funds	$	8,726		$	8,726	$	—	$	—
Commercial paper	40,920			—		40,920		—
Corporate bonds	981,076			—		981,076		—
U.S. government agency obligations	266,142			—		266,142		—
Mutual funds	4,022			4,022		—		—
	$	1,300,886		$	12,748	$	1,288,138	$	—
Liabilities:
Contingent consideration obligation related to completed acquisitions	$	(7,100	)	$	—	$	—	$	(7,100	)

Schedule of Activity of Major Classes of Assets Measured at Fair Value Using Level 3 Inputs

The following table reflects the activity for the Company’s major classes of liabilities measured at fair value using Level 3 inputs for the years ended December 31, 2017 and 2016 (in thousands):

	Other Liabilities: Contingent Consideration Obligation
Balance, January 1, 2016	$	—
Contingent consideration obligation related to Soha acquisition	(1,600		)
Contingent consideration obligation related to Cyberfend acquisition	(5,500		)
Balance, December 31, 2016	$	(7,100	)
Fair value adjustment to contingent consideration included in general and administrative expense	(2,781		)
Cash paid upon achievement of milestone	1,250
Balance, December 31, 2017	$	(8,631	)

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 December 31, 2017 and 2016 were as follows (in thousands):

	December 31, 2017		December 31, 2016
Due in 1 year or less	$	398,554	$	512,572
Due after 1 year through 5 years	559,713		775,566
	$	958,267	$	1,288,138