Fair Value Measurements (Tables)

12 Months Ended

Mar. 31, 2012

Assets measured at fair value on a recurring basis (in details)

Assets measured at fair value on a recurring basis at March 31, 2012 are as follows (amounts in thousands):



	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Money market fund deposits	$	232,219	$	—	$	—	$	232,219
Marketable equity securities	5,264		—		—		5,264
Corporate bonds & debt	—		769,479		4,625		774,104
Government agency bonds	—		342,104		—		342,104
Deposit accounts	—		403,536		—		403,536
Municipal bonds	—		20,122		—		20,122
Auction rate securities	—		—		10,246		10,246
Total assets measured at fair value	$	237,483	$	1,535,241	$	14,871	$	1,787,595

Assets measured at fair value on a recurring basis at March 31, 2011 are as follows (amounts in thousands):



	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Money market fund deposits	$	464,669	$	—	$	—	$	464,669
Marketable equity securities	26,861		—		—		26,861
Corporate bonds & debt	—		519,526		3,500		523,026
Government agency bonds	—		430,591		—		430,591
Deposit accounts	—		239,255		—		239,255
Municipal bonds	—		11,457		—		11,457
Auction rate securities	—		—		12,475		12,475
Total assets measured at fair value	$	491,530	$	1,200,829	$	15,975	$	1,708,334

Reconciliation for all assets measured at fair value on a recurring basis

The following tables present a reconciliation for all assets measured at fair value on a recurring basis, excluding accrued interest components, using significant unobservable inputs (Level 3) for the years ended March 31, 2012 and March 31, 2011 (amounts in thousands):



Year ended March 31, 2012	Auction Rate Securities			Corporate Debt		Total Gains (Losses)
Balance at March 31, 2011	$	12,475		$	3,500	$	—
Total gains or losses (realized and unrealized):
Included in earnings	271			—		271
Included in other comprehensive income (loss)	—			—		—
Purchases, sales, issuances, and settlements, net	(2,500		)	1,125		—
Transfer into Level 3	—			—		—
Transfer out of Level 3	—			—		—
Balance at March 31, 2012	$	10,246		$	4,625	$	271



Year ended March 31, 2011	Auction Rate Securities			Put Option on Auction Rate Securities			Corporate Debt		Total Gains (Losses)
Balance at March 31, 2010	$	37,237		$	1,814		$	—	$	—
Total gains or losses (realized and unrealized):
Included in earnings	138			(1,814		)	—		(1,676		)
Included in other comprehensive income (loss)	—			—			—		—
Purchases, sales, issuances, and settlements, net	(24,900		)	—			3,500		—
Transfer into Level 3	—			—			—		—
Transfer out of Level 3	—			—			—		—
Balance at March 31, 2011	$	12,475		$	—		$	3,500	$	(1,676	)

Fair Value, by Balance Sheet Grouping [Table Text Block]

Assets measured at fair value on a recurring basis are presented/classified on the consolidated balance sheets at March 31, 2012 as follows (amounts in thousands):



	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Cash and cash equivalents	$	232,219	$	403,536	$	—	$	635,755
Short-term investments	782		822,472		—		823,254
Long-term investments	4,482		309,233		14,871		328,586
Total assets measured at fair value	$	237,483	$	1,535,241	$	14,871	$	1,787,595

Assets and liabilities measured at fair value on a recurring basis are presented/classified in the consolidated balance sheets at March 31, 2011 as follows (amounts in thousands):



	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Cash and cash equivalents	$	464,669	$	239,255	$	—	$	703,924
Short-term investments	16,553		523,019		—		539,572
Long-term investments	10,308		438,555		15,975		464,838
Total assets measured at fair value	$	491,530	$	1,200,829	$	15,975	$	1,708,334

- Definition

Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).

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- Definition

Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.

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- Definition

Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

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