Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

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

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

	December 31, 2019
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	84,102	$	—	$	—		$	84,102
Money market funds	58		—		—			58
Commercial paper	3,399		—		—			3,399
Total	87,559		—		—			87,559
Short-term marketable securities:
Commercial paper	2,239		—		—			2,239
Corporate bonds	33,048		51		(1		)	33,098
Asset-backed securities	2,438		11		—			2,449
U.S. government agencies	173,364		184		(3		)	173,545
Total	211,089		246		(4		)	211,331
Long-term marketable securities:
Asset-backed securities	40,001		193		(1		)	40,193
U.S. government agencies	46,447		370		—			46,817
Corporate bonds	32,236		262		—			32,498
Total	118,684		825		(1		)	119,508
Total	$	417,332	$	1,071	$	(5	)	$	418,398

	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	40,913	$	—	$	—		$	40,913
Money market funds	113		—		—			113
Total	41,026		—		—			41,026
Short-term marketable securities:
Commercial paper	3,237		—		—			3,237
Corporate bonds	30,906		—		(84		)	30,822
Asset-backed securities	10,447		—		(15		)	10,432
U.S. government agencies	203,734		9		(94		)	203,649
Total	248,324		9		(193		)	248,140
Long-term marketable securities:
Asset-backed securities	22,945		10		(28		)	22,927
U.S. government agencies	18,804		—		(53		)	18,751
Corporate bonds	35,322		3		(293		)	35,032
Total	77,071		13		(374		)	76,710
Total	$	366,421	$	22	$	(567	)	$	365,876

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 cash equivalents and marketable securities measured on a recurring basis:

	December 31, 2019
	Level 1		Level 2		Fair Value
	(in thousands)
Money market funds	$	58	$	—	$	58
Commercial paper	—		5,638		5,638
U.S. government agencies	—		220,362		220,362
Corporate bonds	—		65,596		65,596
Asset-backed securities	—		42,642		42,642
Total	$	58	$	334,238	$	334,296

	December 31, 2018
	Level 1		Level 2		Fair Value
	(in thousands)
Money market funds	$	113	$	—	$	113
Commercial paper	—		3,237		3,237
U.S. government agencies	—		222,400		222,400
Corporate bonds	—		65,854		65,854
Asset-backed securities	—		33,359		33,359
Total	$	113	$	324,850	$	324,963

Schedule of Investments Classified by Contractual Maturity

The following summarizes the fair value of marketable securities classified as available-for-sale debt securities by contractual maturity:

	December 31, 2019
	Mature within One Year		After One Year through Two Years		Over Two Years		Fair Value
	(in thousands)
Commercial paper	$	5,638	$	—	$	—	$	5,638
U.S. government agencies	173,546		46,816				220,362
Corporate bonds	33,098		23,251		9,247		65,596
Asset-backed securities	2,449		15,550		24,643		42,642
Total	$	214,731	$	85,617	$	33,890	$	334,238

Fair Value, by Balance Sheet Grouping [Table Text Block]

The following summarizes derivative financial instruments as of December 31, 2019 and 2018:

	December 31,
	2019			2018
Assets:	(in thousands)
Foreign currency forward contracts designated as cash flow hedge	$	427		$	32
Foreign currency forward contracts not designated as hedging instruments	515			—
Total	$	942		$	32
Liabilities:
Foreign currency forward contracts designated as cash flow hedge	$	(524	)	$	(72	)
Foreign currency forward contracts not designated as hedging instruments	(550		)	(44		)
Total	$	(1,074	)	$	(116	)

Derivative Instruments, Gain (Loss) [Table Text Block]

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

	Year Ended December 31,
	2019			2018			2017
Net gains (losses) from forward contracts	$	438		$	543		$	(1,665	)
Other foreign currency transaction (losses) gains	(792		)	(1,120		)	1,310
Total foreign exchange loss, net	(354		)	(577		)	(355		)
Other expenses	(253		)	(224		)	(181		)
Other income (expense), net	$	(607	)	$	(801	)	$	(536	)