Equity Incentive Plans (Tables)

12 Months Ended

Mar. 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-based compensation expense

The following table presents the details of the Company's share-based compensation expense (amounts in thousands):

	Year Ended March 31,
	2012			2011			2010
Cost of sales	$	5,648	(1)	$	6,825	(1)	$	7,054	(1)
Research and development	14,719			12,874			12,194
Selling, general and administrative	17,922			17,113			17,530
Pre-tax effect of share-based compensation	38,289			36,812			36,778
Income tax benefit	4,889			4,493			4,563
Net income effect of share-based compensation	$	33,400		$	32,319		$	32,215

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

RSU share activity under the 2004 Plan is set forth below:

	Number of Shares
Nonvested shares at March 31, 2009	3,601,772
Granted	1,846,241
Forfeited/expired	(120,198	)
Vested	(689,867	)
Nonvested shares at March 31, 2010	4,637,948
Granted	1,766,257
Forfeited/expired	(171,967	)
Vested	(990,932	)
Nonvested shares at March 31, 2011	5,241,306
Granted	1,627,191
Forfeited/expired	(184,926	)
Vested	(1,191,351	)
Nonvested shares at March 31, 2012	5,492,220

Schedule of Share-based Compensation, Stock Options, Activity

Option activity under the Company's stock inventive plans in the three years ended March 31, 2012 is set forth below:

			Weighted
	Number of		Average Exercise
	Shares		Price per Share
Outstanding at March 31, 2009	10,081,533		$	24.20
Granted	12,000		27.03
Exercised	(1,492,866	)	22.03
Canceled	(140,888	)	27.79
Outstanding at March 31, 2010	8,459,779		24.52
Granted	—		—
Exercised	(2,885,365	)	23.09
Canceled	(77,490	)	29.39
Outstanding at March 31, 2011	5,496,924		25.21
Granted	—		—
Exercised	(2,129,260	)	25.53
Canceled	(6,667	)	25.05
Outstanding at March 31, 2012	3,360,997		$	25.00

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The fair values per share of stock options granted in the year ended March 31, 2010 were estimated utilizing the following assumptions:

	Year Ended March 31,
	2010
Expected term (in years)	6.50
Volatility	36	%
Risk-free interest rate	2.57	%
Dividend yield	5.00	%