Investments

Available-for-Sale Securities

Available-for-sale investments at March 30, 2014 were as follows:



(in thousands)	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government treasuries and agencies securities	$	112,268		$	76	$	(91	)	$	112,253
Money market funds	53,430			—		—			53,430
Asset-backed securities	22,330			11		(9		)	22,332
Corporate bonds	199,598			335		(127		)	199,806
International government bonds	3,023			—		(9		)	3,014
Corporate commercial paper	6,246			—		—			6,246
Bank deposits	18,538			—		—			18,538
Repurchase agreements	46			—		—			46
Municipal bonds	9,196			32		(18		)	9,210
Total available-for-sale investments	424,675			454		(254		)	424,875
Less amounts classified as cash equivalents	(62,271		)	—		—			(62,271		)
Short-term investments	$	362,404		$	454	$	(254	)	$	362,604

Available-for-sale investments at March 31, 2013 were as follows:



(in thousands)	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government treasuries and agencies securities	$	87,356		$	24	$	(1	)	$	87,379
Money market funds	79,083			—		—			79,083
Asset-backed securities	9,860			2		(7		)	9,855
Corporate bonds	58,733			33		(50		)	58,716
International government bonds	3,069			1		(4		)	3,066
Bank deposits	16,583			—		—			16,583
Municipal bonds	2,089			5		—			2,094
Total available-for-sale investments	256,773			65		(62		)	256,776
Less amounts classified as cash equivalents	(90,443		)	—		—			(90,443		)
Short-term investments	$	166,330		$	65	$	(62	)	$	166,333

The cost and estimated fair value of available-for-sale debt securities at March 30, 2014, by contractual maturity, were as follows:



(in thousands)	Amortized Cost		Estimated Fair Value
Due in 1 year or less	$	173,850	$	173,891
Due in 1-2 years	101,275		101,378
Due in 2-5 years	149,550		149,606
Total investments in available-for-sale debt securities	$	424,675	$	424,875

The cost and estimated fair value of available-for-sale debt securities at March 31, 2013, by contractual maturity, were as follows:



(in thousands)	Amortized Cost		Estimated Fair Value
Due in 1 year or less	$	186,747	$	186,771
Due in 1-2 years	25,053		25,038
Due in 2-5 years	44,973		44,967
Total investments in available-for-sale debt securities	$	256,773	$	256,776

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses as of March 30, 2014, 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	$	52,783	$	(127	)	$	—	$	—	$	52,783	$	(127	)
Asset-backed securities	11,156		(9		)	—		—		11,156		(9		)
U.S. government treasuries and agencies securities	36,403		(91		)	—		—		36,403		(91		)
Municipal bonds	$	4,000	$	(18	)	—		—		4,000		(18		)
International government bonds	3,014		(9		)	—		—		3,014		(9		)
Total	$	107,356	$	(254	)	$	—	$	—	$	107,356	$	(254	)

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses, as of March 31, 2013, 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	$	32,009	$	(50	)	$	—	$	—	$	32,009	$	(50	)
Asset-backed securities	6,473		(7		)					6,473		(7		)
U.S. government treasuries and agencies securities	3,324		(1		)	—		—		3,324		(1		)
International government bonds	1,007		(4		)	—		—		1,007		(4		)
Total	$	42,813	$	(62	)	$	—	$	—	$	42,813	$	(62	)

Currently, a significant portion of the Company’s available-for-sale investments that it holds are high grade instruments. As of March 30, 2014, 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 March 30, 2014 or March 31, 2013.

Non-Marketable Equity Securities

The Company accounts for its equity investments in privately held companies under the cost method. These investments are subject to periodic impairment review and measured and recorded at fair value when they are deemed to be other-than-temporarily impaired. In determining whether a decline in value of its investment has occurred and is other than temporary, an assessment was made by considering available evidence, including the general market conditions, the investee’s financial condition, near-term prospects, market comparables and subsequent rounds of financing. The valuation also takes into account the investee’s capital structure, liquidation preferences for its capital and other economic variables. The valuation methodology for determining the decline in value of non-marketable equity securities is based on inputs that require management's judgment.

During fiscal 2013, the Company determined that the carrying values of two of its non-marketable private equity investments were impaired and recorded a $1.7 million other-than-temporary impairment loss during the period. During fiscal 2012 the Company determined that the carrying values of two of its non-marketable private equity investments were impaired and recorded a $3.4 million other-than-temporary impairment loss during the period. Also during fiscal 2012, the Company sold a non-marketable equity security for $2.6 million and recorded a gain on sale of $0.6 million in the period. The aggregate carrying value of the Company’s non-marketable equity securities was zero as of March 30, 2014 and March 31, 2013, respectively. The Company did not recognize any impairment loss in fiscal 2014.