Marketable Securities

9 Months Ended

Oct. 31, 2012

Note 2. Marketable Securities

At October 31, 2012, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses			Aggregate Fair Value
U.S. agency obligations	$	608,658	$	22	$	(5	)	$	608,675
U.S. treasury securities		70,147		—		(1	)		70,146
Commercial paper		42,697		—		—			42,697
Certificates of deposit		250		—		—			250
U.S. corporate securities		12,026		2		(1	)		12,027
Municipal securities		1,361		—		(1	)		1,360
Money market funds		51,047		—		—			51,047

	$	786,186	$	24	$	(8	)	$	786,202

Included in cash and cash equivalents	$	431,805	$	2	$	(2	)	$	431,805

Included in marketable securities	$	354,381	$	22	$	(6	)	$	354,397

At January 31, 2012, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses			Aggregate Fair Value
U.S. agency obligations	$	14,316	$	—	$	—		$	14,316
Commercial paper		23,785		1		(1	)		23,785
U.S. corporate securities		20,391		—		(11	)		20,380
Municipal securities		15,125		1		(1	)		15,125
Money market funds		27,152		—		—			27,152

	$	100,769	$	2	$	(13	)	$	100,758

Included in cash and cash equivalents	$	47,125	$	—	$	(1	)	$	47,124

Included in marketable securities	$	53,644	$	2	$	(12	)	$	53,634

We do not believe the unrealized losses represent other-than-temporary impairments based on our evaluation of available evidence as of January 31, 2012. All marketable securities held as of January 31, 2012 have not been in a continuous unrealized loss position for more than 12 months. Sales of available-for-sale securities resulted in no gains or losses during any of the periods presented. All of our marketable securities as of October 31, 2012 and January 31, 2012 mature within one year. Marketable securities on the balance sheets consist of securities with original or remaining maturities at the time of purchase of greater than three months and the remainder of the securities are reflected in cash and cash equivalents.