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)
December 31, 2013
Cash and cash equivalents:
Cash and money market funds	$	569,299	$	—	$	—		$	569,299
Total cash and cash equivalents	$	569,299	$	—	$	—		$	569,299
Marketable securities:
Government-sponsored enterprise securities (due within 1 year)	$	600,496	$	7	$	(53	)	$	600,450
Commercial paper (due within 1 year)	83,384		109		—			83,493
Corporate debt securities (due within 1 year)	189,674		14		(34		)	189,654
Corporate debt securities (due after 1 year through 5 years)	22,181		6		(7		)	22,180
Total marketable securities	$	895,735	$	136	$	(94	)	$	895,777
Total cash, cash equivalents and marketable securities	$	1,465,034	$	136	$	(94	)	$	1,465,076

December 31, 2012
Cash and cash equivalents:
Cash and money market funds	$	489,407	$	—	$	—		$	489,407
Total cash and cash equivalents	$	489,407	$	—	$	—		$	489,407
Marketable securities:
U.S. Treasury securities (due within 1 year)	$	111,350	$	2	$	(2	)	$	111,350
Government-sponsored enterprise securities (due within 1 year)	440,181		49		(5		)	440,225
Commercial paper (due within 1 year)	225,294		155		—			225,449
Corporate debt securities (due within 1 year)	15,429		1		(1		)	15,429
Corporate debt securities (due after 1 year through 5 years)	39,358		10		(13		)	39,355
Total marketable securities	$	831,612	$	217	$	(21	)	$	831,808
Total cash, cash equivalents and marketable securities	$	1,321,019	$	217	$	(21	)	$	1,321,215