Investments (Tables)

6 Months Ended

Jun. 30, 2016

Investments Schedule [Abstract]

Schedule of available-for-sale marketable securities

The following tables summarize available-for-sale marketable securities (in thousands):

Balance as of June 30, 2016:
	Cost			Gross Unrealized Gain			Gross Unrealized Loss			Estimated Fair Value
Short-term investments:
Asset-backed securities	$	51,338		$	43		$	(34	)	$	51,347
Commercial paper	75,678			21			—			75,699
Corporate debt securities	80,827			27			(20		)	80,834
Government agency securities	31,208			50			(1		)	31,257
Other securities	8,711			1			—			8,712
Amounts classified as cash equivalents	(24,694		)	(1		)	1			(24,694		)
Total short-term investments	$	223,068		$	141		$	(54	)	$	223,155
Investments:
Asset-backed securities	$	17,199		$	28		$	—		$	17,227
Corporate debt securities	33,824			123			(8		)	33,939
Government agency securities	—			—			—			—
Other securities	4,000			18			—			4,018
Total investments	$	55,023		$	169		$	(8	)	$	55,184

Balance as of December 31, 2015:
	Cost			Gross Unrealized Gain		Gross Unrealized Loss			Estimated Fair Value
Short-term investments:
Asset-backed securities	$	52,102		$	—	$	(129	)	$	51,973
Commercial paper	76,711			3		(9		)	76,705
Corporate debt securities	81,777			—		(177		)	81,600
Government agency securities	12,701			—		(17		)	12,684
Other securities	15,122			7		(1		)	15,128
Amounts classified as cash equivalents	(27,943		)	—		—			(27,943		)
Total short-term investments	$	210,470		$	10	$	(333	)	$	210,147
Investments:
Asset-backed securities	$	11,884		$	—	$	(66	)	$	11,818
Corporate debt securities	36,530			3		(119		)	36,414
Government agency securities	11,999			—		(55		)	11,944
Other securities	2,001			—		(2		)	1,999
Total investments	$	62,414		$	3	$	(242	)	$	62,175

Schedule of marketable securities with unrealized losses

The following table summarizes the fair value of the Company’s marketable securities with unrealized losses at June 30, 2016 and December 31, 2015, and the duration of time that such losses had been unrealized (in thousands):

Balance as of June 30, 2016:
	Less Than 12 months					More than 12 months					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Asset-backed securities	$	15,746	$	(9	)	$	2,079	$	(25	)	$	17,825	$	(34	)
Corporate debt securities	29,513		(21		)	5,844		(7		)	35,357		(28		)
Other securities	—		—			2,000		—			2,000		—
Total	$	45,259	$	(30	)	$	9,923	$	(32	)	$	55,182	$	(62	)

Balance as of December 31, 2015:
	Less Than 12 months					More than 12 months					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Asset-backed securities	$	57,866	$	(192	)	$	5,923	$	(3	)	$	63,789	$	(195	)
Corporate debt securities	101,701		(289		)	8,911		(7		)	110,612		(296		)
Government agency securities	24,628		(72		)	—		—			24,628		(72		)
Commercial Paper	11,374		(9		)	—		—			11,374		(9		)
Other securities	7,496		(3		)	—		—			7,496		(3		)
Total	$	203,065	$	(565	)	$	14,834	$	(10	)	$	217,899	$	(575	)

Schedule of amortized cost and estimated fair value of available-for-sale debt securities by contractual maturity

The following table summarizes the amortized cost and estimated fair value of available-for-sale debt securities at June 30, 2016 and December 31, 2015, by contractual maturity (in thousands):

	June 30, 2016				December 31, 2015
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Mature in one year or less	$	179,418	$	179,473	$	186,311	$	186,118
Mature after one year through three years	111,507		111,730		106,377		106,086
Mature in more than three years	11,860		11,831		8,139		8,061
Total	$	302,785	$	303,034	$	300,827	$	300,265