Marketable Securities

A summary of the Company’s cash, cash equivalents and marketable securities is shown below:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
As of March 31, 2015
Cash and cash equivalents:
Cash and money market funds	$	664,879	$	—	$	—		$	664,879
Total cash and cash equivalents	$	664,879	$	—	$	—		$	664,879
Marketable securities:
Government-sponsored enterprise securities (due within 1 year)	$	284,126	$	5	$	(16	)	$	284,115
Commercial paper (due within 1 year)	59,688		57		—			59,745
Corporate debt securities (due within 1 year)	148,958		18		(24		)	148,952
Corporate debt securities (due after 1 year through 5 years)	23,430		13		—			23,443
Total marketable securities	$	516,202	$	93	$	(40	)	$	516,255
Total cash, cash equivalents and marketable securities	$	1,181,081	$	93	$	(40	)	$	1,181,134

As of December 31, 2014
Cash and cash equivalents:
Cash and money market funds	$	625,259	$	—	$	—		$	625,259
Total cash and cash equivalents	$	625,259	$	—	$	—		$	625,259
Marketable securities:
Government-sponsored enterprise securities (due within 1 year)	$	463,788	$	14	$	(52	)	$	463,750
Commercial paper (due within 1 year)	51,674		72		—			51,746
Corporate debt securities (due within 1 year)	196,065		2		(66		)	196,001
Corporate debt securities (due after 1 year through 5 years)	50,443		—		(93		)	50,350
Total marketable securities	$	761,970	$	88	$	(211	)	$	761,847
Total cash, cash equivalents and marketable securities	$	1,387,229	$	88	$	(211	)	$	1,387,106

The Company has a limited number of marketable securities in insignificant loss positions as of March 31, 2015, which the Company does not intend to sell and has concluded it will not be required to sell before recovery of the amortized costs for the investment at maturity. There were no charges recorded for other-than-temporary declines in fair value of marketable securities nor gross realized gains or losses recognized in the three months ended March 31, 2015 and 2014.