Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of Cash and Cash Equivalents, Available-for-sale Securities Reconciliation

The Company's cash and cash equivalents, short-term investments, and long-term investments consist of the following:

	September 30, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	90,472	$	—	$	—		$	90,472
Money market funds	45		—		—			45
Total	90,517		—		—			90,517
Short-term investments:
Commercial paper	20,930		4		(1		)	20,933
Corporate bonds	31,786		3		(22		)	31,767
Asset-backed securities	491		—		—			491
U.S. government agencies	159,135		3		(119		)	159,019
Total	212,342		10		(142		)	212,210
Long-term investments:
Asset-backed securities	2,855		1		—			2,856
Corporate bonds	37,490		32		(20		)	37,502
Total	40,345		33		(20		)	40,358
Total	$	343,204	$	43	$	(162	)	$	343,085

	December 31, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	72,673	$	—	$	—		$	72,673
Money market funds	473		—		—			473
Commercial paper	13,591		—		—			13,591
Total	86,737		—		—			86,737
Short-term investments:
Commercial paper	14,782		5		—			14,787
Corporate bonds	13,490		—		(11		)	13,479
Asset-backed securities	1,235							1,235
U.S. government agencies	127,660				(42		)	127,618
Total	157,167		5		(53		)	157,119
Long-term investments:
Asset-backed securities	5,091		2		—			5,093
U.S. government agencies	29,501		—		(71		)	29,430
Corporate bonds	11,243		—		(41		)	11,202
Total	45,835		2		(112		)	45,725
Total	$	289,739	$	7	$	(165	)	$	289,581

Schedule of changes to accumulated other comprehensive income

The following table shows the changes to accumulated other comprehensive income (loss) for the nine months ended September 30, 2017 (in thousands):

	Unrealized Gain (Loss), net on Investments
Balance at December 31, 2016	$	(156	)
Change in net realized gain (loss) on investments	32
Amounts reclassified for net realized gain (loss) included in net income	4
Other comprehensive income (loss), net	36
Balance at September 30, 2017	$	(120	)

Schedule of Assets Measured on Recurring Basis

The following table sets forth by level within the fair value hierarchy the fair value of the Company's available-for-sale securities measured on a recurring basis, excluding cash and money market funds:

	September 30, 2017
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	20,933	$	—	$	20,933
U.S. government agencies	—		159,019		—		159,019
Corporate bonds	—		69,269		—		69,269
Asset-backed securities	—		3,347		—		3,347
Total	$	—	$	252,568	$	—	$	252,568

	December 31, 2016
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	28,378	$	—	$	28,378
U.S. government agencies	—		157,048		—		157,048
Corporate bonds	—		24,681		—		24,681
Asset-backed securities	—		6,328		—		6,328
Total	$	—	$	216,435	$	—	$	216,435

Schedule of Available-for-Sale Securities by Contractual Maturity

The following summarizes the fair value of securities classified as available-for-sale by contractual, or effective, maturity:

	September 30, 2017
	Mature within One Year		After One Year through Two Years		Over Two Years		Fair Value
	(in thousands)
Commercial paper	$	20,933	$	—	$	—	$	20,933
U.S. government agencies	159,019		—		—		159,019
Corporate bonds	32,783		27,037		9,449		69,269
Asset-backed securities	1,781		1,000		566		3,347
Total	$	214,516	$	28,037	$	10,015	$	252,568

Summary of Gains (Losses) Recognized From Forward Contracts and Other Foreign Currency Transactions

The following summarizes the gains (losses) recognized in Other expense, net on the condensed consolidated statement of operations, from forward contracts and other foreign currency transactions:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2017			2016			2017			2016
	(in thousands)
Net loss from forward contracts	$	(463	)	$	(82	)	$	(1,585	)	$	(9	)
Other foreign currency transactions gain	431			(2		)	1,424			(276		)
Total foreign exchange gain (loss), net	$	(32	)	$	(84	)	$	(161	)	$	(285	)