Marketable Securities (Tables)

12 Months Ended

Jan. 31, 2015

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

The amortized cost, gross unrealized gains (losses) and fair values of available-for-sale securities by major security type and class of security as of January 31, 2015 and 2014 are as follows:


	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Fair Value
As of January 31, 2015
Short-term Investments:
Corporate bonds	$	56,594	$	20	$	(24	)	$	56,590
Municipal and pre-refunded municipal bonds		30,509		41		(2	)		30,548
Certificates of deposit		11,127		5		—			11,132
Treasury bills		2,033		3		—			2,036
Commercial paper		3,938		2		—			3,940

		104,201		71		(26	)		104,246

Long-term Investments:
Corporate bonds		46,754		22		(40	)		46,736
Municipal and pre-refunded municipal bonds		42,840		113		(6	)		42,947
Certificates of deposit		3,066		—		—			3,066
Treasury bills		7,111		9		—			7,120
Mutual funds, held in rabbi trust		3,816		16		(54	)		3,778
Federal government agencies		799		2		—			801

		104,386		162		(100	)		104,448

	$	208,587	$	233	$	(126	)	$	208,694

As of January 31, 2014
Short-term Investments:
Corporate bonds	$	100,856	$	56	$	(41	)	$	100,871
Municipal and pre-refunded municipal bonds		85,000		98		(2	)		85,096
Certificates of deposit		35,844		13		(1	)		35,856
Treasury bills		24,873		10		—			24,883
Commercial paper		35,101		7		(1	)		35,107

		281,674		184		(45	)		281,813

Long-term Investments:
Corporate bonds		208,446		268		(162	)		208,552
Municipal and pre-refunded municipal bonds		125,934		415		(8	)		126,341
Certificates of deposit		4,000		—		(2	)		3,998
Treasury bills		21,551		21		—			21,572
Mutual funds, held in rabbi trust		1,591		108		(33	)		1,666
Federal government agencies		4,287		6		—			4,293

		365,809		818		(205	)		366,422

	$	647,483	$	1,002	$	(250	)	$	648,235

Gross Unrealized Losses and Fair Value of Marketable Securities

The following tables show the gross unrealized losses and fair value of the Company’s marketable securities with unrealized losses that are not deemed to be other-than-temporarily impaired aggregated by the length of time that individual securities have been in a continuous unrealized loss position, at January 31, 2015 and January 31, 2014, respectively.


	January 31, 2015
	Less Than 12 Months					12 Months or Greater					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate bonds	$	55,384	$	(63	)	$	383	$	(1	)	$	55,767	$	(64	)
Municipal and pre-refunded municipal bonds		4,672		(8	)		—		—			4,672		(8	)
Certificates of deposit		1,600		—			—		—			1,600		—
Treasury bills		—		—			—		—			—		—
Commercial paper		747		—			—		—			747		—
Mutual funds, held in rabbi trust		3,778		(54	)		—		—			3,778		(54	)
Federal government agencies		—		—			—		—			—		—

Total	$	66,181	$	(125	)	$	383	$	(1	)	$	66,564	$	(126	)


	January 31, 2014
	Less Than 12 Months					12 Months or Greater					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate bonds	$	147,731	$	(203	)	$	—	$	—		$	147,731	$	(203	)
Municipal and pre-refunded municipal bonds		6,291		(10	)		—		—			6,291		(10	)
Certificates of deposit		12,746		(3	)		—		—			12,746		(3	)
Treasury bills		6,606		—			—		—			6,606		—
Commercial paper		6,640		(1	)		—		—			6,640		(1	)
Mutual funds, held in rabbi trust		1,666		(33	)		—		—			1,666		(33	)
Federal government agencies		1,753		—			—		—			1,753		—

Total	$	183,433	$	(250	)	$	—	$	—		$	183,433	$	(250	)

- 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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