Stock-Based Compensation Plans (Tables)

12 Months Ended

Mar. 31, 2012

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-Based compensation expense

(In thousands)	2012			2011			2010
Stock-based compensation included in:
Cost of revenues	$	5,630		$	4,825		$	5,180
Research and development		32,310			28,780			25,766
Selling, general and administrative		29,478			26,653			24,590
Restructuring charges		—			—			945
Stock-based compensation effect on income before taxes		67,418			60,258			56,481
Income tax effect		(19,214	)		(18,561	)		(17,105	)
Net stock-based compensation effect on net income	$	48,204		$	41,697		$	39,376

Summary of options outstanding

	Stock Options									Employee Stock Purchase Plan
	2012			2011			2010			2012			2011			2010
Expected life of options (years)		5.1			5.1			5.2			1.3			1.3			1.3
Expected stock price volatility		0.31			0.35			0.35			0.29			0.31			0.33
Risk-free interest rate		1.1	%		1.8	%		2.5	%		0.2	%		0.3	%		0.6	%
Dividend yield		2.4	%		2.5	%		2.7	%		2.4	%		2.3	%		2.5	%

Summary of shares available for grant

	2012			2011			2010
Risk-free interest rate		0.7	%		1.0	%		1.6	%
Dividend yield		2.2	%		2.5	%		2.7	%

Summary of option plans activity

(Shares and intrinsic value in thousands)	Number of Shares		Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (1)
Vested (i.e., exercisable)		15,349	$	28.78		2.84	$	133,990
Expected to vest		2,323	$	25.51		5.12	$	25,474
Total vested and expected to vest		17,672	$	28.35		3.14	$	159,464
Total outstanding		17,788	$	28.32		3.14	$	160,941

Stock options Plans under outstanding and exercisable

(Shares in thousands)	Shares Available for Grant
March 28, 2009		11,052
Additional shares reserved		5,000
Stocks options granted		(2,461	)
Stock options cancelled		314
RSUs granted		(1,885	)
RSUs cancelled		302
April 3, 2010		12,322
Additional shares reserved		4,500
Stocks options granted		(2,345	)
Stock options cancelled		365
RSUs granted		(2,043	)
RSUs cancelled		365
April 2, 2011		13,164
Additional shares reserved		4,500
Stocks options granted		(207	)
Stock options cancelled		70
RSUs granted		(2,977	)
RSUs cancelled		358
March 31, 2012		14,908

Summary of restricted stock unit activity and related information

	Options Outstanding
(Shares in thousands)	Number of Shares			Weighted-Average Exercise Price Per Share
March 28, 2009		41,021		$	32.51
Granted		2,461		$	21.19
Exercised		(1,600	)	$	22.95
Forfeited/cancelled/expired		(10,856	)	$	37.04
April 3, 2010		31,026		$	30.51
Granted		2,345		$	26.36
Exercised		(5,704	)	$	25.42
Forfeited/cancelled/expired		(2,698	)	$	50.69
April 2, 2011		24,969		$	29.11
Granted		207		$	34.79
Exercised		(3,622	)	$	24.70
Forfeited/cancelled/expired		(3,766	)	$	37.35
March 31, 2012		17,788		$	28.32

Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Weighted-average assumptions in estimation of fair value of employee purchase plan

	Options Outstanding						Options Exercisable
			Weighted-		Weighted-				Weighted-
(Shares in thousands)			Average		Average				Average
			Remaining		Exercise				Exercise
Range of	Options		Contractual Term		Price Per		Options		Price Per
Exercise Prices	Outstanding		(Years)		Share		Exercisable		Share
$15.95 - $19.98		292		2.9	$	18.29		247	$	18.38
$20.14 - $29.93		12,512		3.6	$	24.30		10,525	$	24.36
$30.04 - $38.51		1,450		3.4	$	34.59		1,043	$	35.12
$40.11 - $42.46		3,534		1.4	$	40.82		3,534	$	40.82
		17,788		3.1	$	28.32		15,349	$	28.78

Restricted Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Weighted-average assumptions in estimation of fair value of employee purchase plan

	RSUs Outstanding
(Shares and intrinsic value in thousands)	Number of Shares			Weighted- Average Grant- Date Fair Value Per Share		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (1)
March 28, 2009		2,970		$	22.99
Granted		1,885		$	20.38
Vested (2)		(901	)	$	22.16
Cancelled		(302	)	$	22.56
April 3, 2010		3,652		$	21.70
Granted		2,043		$	25.14
Vested (2)		(1,192	)	$	22.23
Cancelled		(288	)	$	21.99
April 2, 2011		4,215		$	23.19
Granted		2,977		$	33.69
Vested (2)		(1,543	)	$	23.11
Cancelled		(410	)	$	25.18
March 31, 2012		5,239		$	29.01		2.7	$	191,126
Expected to vest as of March 31, 2012		4,729		$	29.15		2.6	$	172,513