Fair Value Measurements (Tables)

6 Months Ended

Sep. 30, 2012

Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]

Schedule of Fair Value, Assets and LIabilities Measured on Recurring Basis

Assets and liabilities measured at fair value on a recurring basis at September 30, 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	$	137,836	$	—	$	—	$	137,836
Marketable equity securities	4,435		—		—		4,435
Corporate bonds and debt	—		725,686		5,681		731,367
Government agency bonds	—		480,505		—		480,505
Deposit accounts	—		298,899		—		298,899
Municipal bonds	—		20,068		—		20,068
Auction rate securities	—		—		34,302		34,302
Total assets measured at fair value	$	142,271	$	1,525,158	$	39,983	$	1,707,412
Liabilities
Contingent consideration	$	—	$	—	$	16,632	$	16,632
Total liabilities measured at fair value	$	—	$	—	$	16,632	$	16,632

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
Money market fund deposits	$	232,219	$	—	$	—	$	232,219
Marketable equity securities	5,264		—		—		5,264
Corporate bonds and 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

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

The following tables present a reconciliation for all assets and liabilities measured at fair value on a recurring basis, excluding accrued interest components, using significant unobservable inputs (Level 3) for the three months ended September 30, 2012, and the year ended March 31, 2012 (amounts in thousands):

Six months ended September 30, 2012	Auction Rate  Securities			Corporate Debt		Contingent Consideration		Total Losses
Balance at March 31, 2012	$	10,246		$	4,625	$	—	$	—
Total gains or losses (realized and unrealized):
Included in earnings	(334		)	—		—		(334		)
Purchases, sales, issuances, and settlements, net	—			1,056		—		—
Additions	24,390			—		16,632		—
Balance at September 30, 2012	$	34,302		$	5,681	$	16,632	$	(334	)

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

Fair Value, by Balance Sheet Grouping

Assets measured at fair value on a recurring basis are presented/classified on the condensed consolidated balance sheets at September 30, 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
Cash and cash equivalents	$	137,836	$	298,899	$	—	$	436,735
Short-term investments	—		1,116,675		—		1,116,675
Long-term investments	4,435		109,584		39,983		154,002
Total assets measured at fair value	$	142,271	$	1,525,158	$	39,983	$	1,707,412

Assets measured at fair value on a recurring basis are presented/classified in 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
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