Investments

Available-for-Sale Securities

Available-for-sale investments at September 27, 2015 were as follows:



(in thousands)	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government treasuries and agencies securities	$	144,033		$	353	$	(18	)	$	144,368
Money market funds	37,139			—		—			37,139
Asset-backed securities	39,656			17		(17		)	39,656
Corporate bonds	261,206			184		(367		)	261,023
International government bonds	1,007			—		(3		)	1,004
Corporate commercial paper	8,546			—		—			8,546
Bank deposits	14,803			—		—			14,803
Repurchase agreements	128			—		—			128
Municipal bonds	5,978			35		(2		)	6,011
Total available-for-sale investments	512,496			589		(407		)	512,678
Less amounts classified as cash equivalents	(45,314		)	—		—			(45,314		)
Short-term investments	$	467,182		$	589	$	(407	)	$	467,364

Available-for-sale investments at March 29, 2015 were as follows:



(in thousands)	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government treasuries and agencies securities	$	135,570		$	398	$	(23	)	$	135,945
Money market funds	55,578			—		—			55,578
Asset-backed securities	31,830			9		(9		)	31,830
Corporate bonds	245,229			567		(121		)	245,675
International government bonds	1,010			—		(4		)	1,006
Corporate commercial paper	4,999			—		—			4,999
Bank deposits	16,915			—		—			16,915
Repurchase agreements	191			—		—			191
Municipal bonds	6,001			45		(2		)	6,044
Total available-for-sale investments	497,323			1,019		(159		)	498,183
Less amounts classified as cash equivalents	(60,068		)	—		—			(60,068		)
Short-term investments	$	437,255		$	1,019	$	(159	)	$	438,115

The cost and estimated fair value of available-for-sale securities at September 27, 2015, by contractual maturity, were as follows:



(in thousands)	Amortized Cost		Estimated Fair Value
Due in 1 year or less	$	130,921	$	130,974
Due in 1-2 years	142,268		142,417
Due in 2-5 years	239,299		239,287
Total investments in available-for-sale securities	$	512,488	$	512,678

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses as of September 27, 2015, aggregated by investment category and length of time that individual securities have been in a continuous loss position.



	Less Than 12 Months					12 Months or Greater				Total
(in thousands)	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	151,943	$	(366	)	$	—	$	—	$	151,943	$	(366	)
Asset-backed securities	17,306		(17		)	—		—		17,306		(17		)
U.S. government treasuries and agencies securities	38,447		(18		)	—		—		38,447		(18		)
Municipal bonds	2,003		(3		)	—		—		2,003		(3		)
International government bonds	1,004		(3		)	—		—		1,004		(3		)
Total	$	210,703	$	(407	)	$	—	$	—	$	210,703	$	(407	)

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses, as of March 29, 2015, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position.



	Less Than 12 Months					12 Months or Greater				Total
(in thousands)	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	67,367	$	(121	)	$	—	$	—	$	67,367	$	(121	)
Asset-backed securities	17,736		(9		)	—		—		17,736		(9		)
U.S. government treasuries and agencies securities	18,478		(23		)	—		—		18,478		(23		)
Municipal bonds	1,001		(2		)	—		—		1,001		(2		)
International government bonds	1,006		(4		)	—		—		1,006		(4		)
Total	$	105,588	$	(159	)	$	—	$	—	$	105,588	$	(159	)

Currently, a significant portion of the Company’s available-for-sale investments that it holds are high grade instruments. As of September 27, 2015, the unrealized losses on the Company’s available-for-sale investments represented an insignificant amount in relation to its total available-for-sale portfolio. Substantially all of the Company’s unrealized losses on its available-for-sale marketable debt instruments can be attributed to fair value fluctuations in an unstable credit environment that resulted in a decrease in the market liquidity for debt instruments. Because the Company has the ability to hold these investments until a recovery of fair value, which may be maturity, the Company did not consider these investments to be other-than-temporarily impaired at September 27, 2015 and March 29, 2015.

Non-marketable Equity Securities

In the quarter ended December 28, 2014, the Company purchased common stock of a privately-held company for $4 million. This investment (included under Other Assets on the Condensed Consolidated Balance Sheets) is accounted for as a cost-method investment, as the Company owns less than 20% of the voting securities and does not have the ability to exercise significant influence over operating and financial policies of the entity. The Company did not record any impairment charge for this investment during the three and six months ended September 27, 2015.