Marketable Securities (Tables)

6 Months Ended

Jul. 31, 2013

Amortized Cost, Gross Unrealized Gains (Losses) and Fair Value of Available-For-Sale Securities

The amortized cost, gross unrealized gains (losses) and fair value of available-for-sale securities by major security type and class of security as of July 31, 2013, January 31, 2013 and July 31, 2012 were as follows:


	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Fair Value
As of July 31, 2013
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	91,819	$	61	$	(9	)	$	91,871
Corporate bonds		79,637		22		(37	)		79,622
Certificates of deposit		29,870		24		—			29,894
Treasury bills		16,115		5		—			16,120
Commercial paper		8,284		8		—			8,292

		225,725		120		(46	)		225,799

Long-term Investments:
Municipal and pre-refunded municipal bonds		100,402		142		(54	)		100,490
Corporate bonds		95,795		51		(239	)		95,607
Certificates of deposit		3,801		1		(2	)		3,800
Treasury bills		8,218		6		—			8,224
Federal government agencies		7,800		—		(7	)		7,793
Mutual funds, held in rabbi trust		817		35		—			852

		216,833		235		(302	)		216,766

	$	442,558	$	355	$	(348	)	$	442,565

As of January 31, 2013
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	63,355	$	85	$	(17	)	$	63,423
Corporate bonds		88,432		106		(23	)		88,515
Certificates of deposit		40,870		25		—			40,895
Treasury bills		21,354		14		—			21,368
Commercial paper		10,775		8		(2	)		10,781
Federal government agencies		3,500		4		—			3,504

		228,286		242		(42	)		228,486

Long-term Investments:
Municipal and pre-refunded municipal bonds		52,925		76		(60	)		52,941
Corporate bonds		64,219		102		(61	)		64,260
Certificates of deposit		2,340		—		—			2,340
Treasury bills		19,724		13		—			19,737
Federal government agencies		5,974		5		(2	)		5,977
Auction rate securities		4,925		—		(595	)		4,330

		150,107		196		(718	)		149,585

	$	378,393	$	438	$	(760	)	$	378,071

As of July 31, 2012
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	28,019	$	95	$	(7	)	$	28,107
Corporate bonds		53,713		71		(8	)		53,776
Certificate of deposit		20,671		13		(2	)		20,682
Treasury bills		21,425		5		—			21,430
Commercial paper		7,279		8		—			7,287
Federal government agencies		4,608		—		—			4,608

		135,715		192		(17	)		135,890

Long-term Investments:
Municipal and pre-refunded municipal bonds		24,646		78		(23	)		24,701
Corporate bonds		47,905		150		(18	)		48,037
Certificate of deposit		4,514		2		—			4,516
Treasury bills		8,855		10		—			8,865
Federal government agencies		1,213		2		—			1,215
Auction rate securities		4,925		—		(595	)		4,330

		92,058		242		(636	)		91,664

	$	227,773	$	434	$	(653	)	$	227,554

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

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