Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2014

Investments Debt And Equity Securities [Abstract]

Summary of Held-to-Maturity Marketable Securities

The amortized cost, unrealized gains and losses and estimated fair value of the Company’s held-to-maturity marketable securities as of December 31, 2014 were as follows:

	December 31, 2014
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash and cash equivalents
Corporate bonds	$	1,882	$	1	$	(1	)	$	1,882
Short term investments		—		—		—			—
Commercial paper		38,081		—		(26	)		38,055
Corporate bonds		73,260		2		(64	)		73,198
Total	$	113,223	$	3	$	(91	)	$	113,135

Summary of Continuous Unrealized Loss on Marketable Securities

The gross unrealized losses, estimated fair value and length of time the individual marketable securities were in a continuous loss position for those marketable securities in an unrealized loss position as of December 31, 2014 were as follows:

	December 31, 2014
	Less Than 12 Months					12 Months or Greater				Total
	Estimated FairValue		Unrealized Loss			Estimated FairValue		UnrealizedLoss		Estimated Fair Value		Unrealized Loss
	(in thousands)
Commercial paper	$	38,055	$	(26	)	$	—	$	—	$	38,055	$	(26	)
Corporate bonds		64,557		(65	)		—		—		64,557		(65	)
Total	$	102,612	$	(91	)	$	—	$	—	$	102,612	$	(91	)