Marketable securities (Tables)

6 Months Ended

Sep. 30, 2013

Available-for-sale debt securities consist of the following:

(In thousands)	September 30, 2013
	Estimated fair value		Gains in accumulated other comprehensive income		Losses in accumulated other comprehensive income
Current:
Municipal bonds and notes	$	11,727	$	11	$	–
Government agency bonds		75,462		169		(1	)
Commercial paper		82,357		–		–
Certificates of deposit		99,966		22		(15	)
Corporate bonds		487,845		981		(148	)
Total current securities		757,357		1,183		(164	)

Non-current:
Municipal bonds and notes		7,895		24		–
Government agency bonds		178,710		184		(226	)
Commercial paper		2,850		–		–
Certificates of deposit		3,000		–		–
Corporate bonds		1,143,934		3,040		(5,652	)
Auction rate securities		3,198		–		–
Variable rate demand notes		29,140		–		–
Total non-current securities		1,368,727		3,248		(5,878	)
Total available-for-sale debt securities	$	2,126,084	$	4,431	$	(6,042	)

(In thousands)	March 31, 2013
	Estimated fair value		Gains in accumulated other comprehensive income		Losses in accumulated other comprehensive income
Current:
Municipal bonds and notes	$	34,025	$	34	$	–
Government agency bonds		87,227		125		(10	)
Commercial paper		144,293		–		–
Certificates of deposit		47,977		–		(2	)
Corporate bonds		425,676		1,286		(33	)
Total current securities		739,198		1,445		(45	)

Non-current:
Municipal bonds and notes		12,852		37		–
Government agency bonds		186,577		434		(19	)
Certificates of deposit		22,999		–		–
Corporate bonds		1,084,194		5,290		(2,150	)
Auction rate securities		3,198		–		(752	)
Variable rate demand notes		1,500		–		–
Total non-current securities		1,311,320		5,761		(2,921	)
Total available-for-sale debt securities	$	2,050,518	$	7,206	$	(2,966	)

Contractual maturities of available-for-sale debt securities

Contractual maturities of available-for-sale debt securities at September 30, 2013 are as follows:

(In thousands)

	Estimated fair value
Within one year	$	757,357
1-5 years		1,329,877
5-10 years		4,402
After 10 years		34,448
	$	2,126,084

- 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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