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 June 30, 2013
Cash and cash equivalents:
Cash and money market funds	$	530,567	$	—	$	—		$	530,567
U.S. Treasury securities	680		—		—			680
Total cash and cash equivalents	$	531,247	$	—	$	—		$	531,247
Marketable securities:
U.S. Treasury securities (due within 1 year)	$	3,050	$	—	$	—		$	3,050
Government-sponsored enterprise securities (due within 1 year)	598,440		17		(46		)	598,411
Commercial paper (due within 1 year)	192,702		176		—			192,878
Corporate debt securities (due within 1 year)	105,220		—		(110		)	105,110
Total marketable securities	$	899,412	$	193	$	(156	)	$	899,449
Total cash, cash equivalents and marketable securities	$	1,430,659	$	193	$	(156	)	$	1,430,696

As of 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

Alios’ $58.3 million and $70.0 million, respectively, of cash and money market funds as of June 30, 2013 and December 31, 2012, recorded on the Company’s condensed consolidated balance sheets in “Restricted cash and cash equivalents (Alios),” are not included in the above table.