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)
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
December 31, 2011
Cash and cash equivalents:
Cash and money market funds	$	362,035	$	—	$	—		$	362,035
Government-sponsored enterprise securities	113,302		—		(17		)	113,285
Total cash and cash equivalents	$	475,337	$	—	$	(17	)	$	475,320
Marketable securities:
U.S. Treasury securities (due within 1 year)	$	22,105	$	2	$	—		$	22,107
Government-sponsored enterprise securities (due within 1 year)	471,589		8		(102		)	471,495
Total marketable securities	$	493,694	$	10	$	(102	)	$	493,602
Total cash, cash equivalents and marketable securities	$	969,031	$	10	$	(119	)	$	968,922

Alios’ $70.0 million and $51.9 million, respectively, of cash and money market funds as of December 31, 2012 and 2011, recorded on the Company’s consolidated balance sheets in “Restricted cash and cash equivalents (Alios),” are not included in the above table.