Investments (Tables)

The following tables summarize the Company’s investments (in thousands):


	July 30, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Short-term investments:
Available-for-sale:
Corporate debt securities	$	475,483	$	3,519	$	(154	)	$	478,848
U.S. government and agency debt		206,056		273		(53	)		206,276
Asset backed securities		51,489		132		(13	)		51,608
Foreign government and agency debt		14,603		14		(2	)		14,615
Municipal debt securities		28,873		41		(4	)		28,910
Held-to-maturity:
Time deposits		125,000		—		—			125,000

Total short-term investments		901,504		3,979		(226	)		905,257
Long-term investments:
Available-for-sale:
Auction rate securities		8,974		—		—			8,974

Total long-term investments		8,974		—		—			8,974

Total investments	$	910,478	$	3,979	$	(226	)	$	914,231


	January 30, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Short-term investments:
Available-for-sale:
Corporate debt securities	$	558,337	$	766	$	(1,282	)	$	557,821
U.S. government and agency debt		317,595		64		(254	)		317,405
Asset backed securities		76,711		81		(56	)		76,736
Foreign government and agency debt		21,370		2		(14	)		21,358
Municipal debt securities		31,211		45		(7	)		31,249

Total short-term investments		1,005,224		958		(1,613	)		1,004,569
Long-term investments:
Available-for-sale:
Auction rate securities		11,296		—		—			11,296

Total long-term investments		11,296		—		—			11,296

Total investments	$	1,016,520	$	958	$	(1,613	)	$	1,015,865

Gross realized gains and gross realized losses on sales of available-for-sale securities are presented in the following tables (in thousands):


	Three Months Ended						Six Months Ended
	July 30,			August 1,			July 30,			August 1,
	2016			2015			2016			2015
Gross realized gains	$	280		$	255		$	668		$	698
Gross realized losses		(19	)		(230	)		(243	)		(337	)

Total net realized gains	$	261		$	25		$	425		$	361

The contractual maturities of available-for-sale securities are presented in the following tables (in thousands):


	July 30, 2016				January 30, 2016
	Amortized		Estimated		Amortized		Estimated
	Cost		Fair Value		Cost		Fair Value
Due in one year or less	$	355,835	$	355,931	$	304,117	$	304,035
Due between one and five years		538,247		541,894		689,847		689,279
Due over five years		16,396		16,406		22,556		22,551

	$	910,478	$	914,231	$	1,016,520	$	1,015,865

For individual securities that have been in a continuous unrealized loss position, the fair value and gross unrealized loss for these securities aggregated by investment category and length of time in an unrealized position are presented in the following tables (in thousands):


	July 30, 2016
	Less than 12 months					12 months or more					Total
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
	Value		Loss			Value		Loss			Value		Loss
Corporate debt securities	$	57,734	$	(75	)	$	20,946	$	(79	)	$	78,680	$	(154	)
U.S. government and agency debt		60,760		(46	)		6,993		(7	)		67,753		(53	)
Asset backed securities		7,003		(6	)		3,994		(7	)		10,997		(13	)
Foreign government and agency debt		4,411		(2	)		—		—			4,411		(2	)
Municipal debt securities		1,296		(1	)		1,497		(3	)		2,793		(4	)

Total securities	$	131,204	$	(130	)	$	33,430	$	(96	)	$	164,634	$	(226	)


	January 30, 2016
	Less than 12 months					12 months or more					Total
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
	Value		Loss			Value		Loss			Value		Loss
Corporate debt securities	$	283,138	$	(1,237	)	$	14,383	$	(45	)	$	297,521	$	(1,282	)
U.S. government and agency debt		263,325		(254	)		—		—			263,325		(254	)
Asset backed securities		46,646		(56	)		—		—			46,646		(56	)
Foreign government and agency debt		16,458		(14	)		—		—			16,458		(14	)
Municipal debt securities		2,943		(5	)		1,571		(2	)		4,514		(7	)

Total securities	$	612,510	$	(1,566	)	$	15,954	$	(47	)	$	628,464	$	(1,613	)