Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2015

Investments Debt And Equity Securities [Abstract]

Schedule of Investments

The table below summarizes the Company’s investments (in thousands):

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		(Losses)			Fair Value
March 31, 2015
Cash equivalents:
Money market funds	$	17,089	$	—	$	—		$	17,089
Total		17,089		—		—			17,089
Available-for-sale securities:
Commercial paper securities	$	31,121	$	27	$	—		$	31,148
Corporate debt securities		23,261		5		—			23,266
U.S. government sponsored entity debt securities		146,062		—		(7	)		146,055
Total		200,444		32		(7	)		200,469
Total cash equivalents and available-for-sale securities	$	217,533	$	32	$	(7	)	$	217,558
December 31, 2014
Cash equivalents:
Money market funds	$	3,182	$	—	$	—		$	3,182
Total		3,182		—		—			3,182
Available-for-sale securities:
Commercial paper securities	$	33,715	$	33	$	—		$	33,748
Corporate debt securities		22,831		—		(18	)		22,813
U.S. government sponsored entity debt securities		163,671		—		(40	)		163,631
Total		220,217		33		(58	)		220,192
Total cash equivalents and available-for-sale securities	$	223,399	$	33	$	(58	)	$	223,374