STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Mar. 31, 2013

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

Stock-Based Compensation Expense Included in Statements of Operations

The following table summarizes the amount of stock-based compensation expense included in the consolidated statements of operations for the periods presented:

	Fiscal Year Ended March 31,
(in thousands)	2013			2012			2011
Cost of revenues	$	2,020		$	2,212		$	2,202
Research, development and engineering	4,842			3,917			3,765
Selling, general and administrative	11,488			11,352			9,906
Stock-based compensation expense included in operating expenses	16,330			15,269			13,671
Total stock-based compensation	18,350			17,481			15,873
Income tax benefit	(5,479		)	(5,463		)	(4,892		)
Total stock-based compensation expense, net of tax	$	12,871		$	12,018		$	10,981

Summary of Stock Option Activity

The following is a summary of the Company’s stock option activity during fiscal year 2013:

	Options Outstanding
	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value
	(in thousands)				(in years)	(in thousands)
Outstanding at March 31, 2012	3,304		$	26.47
Options granted	428		$	33.23
Options exercised	(1,110	)	$	24.37
Options forfeited or expired	(207	)	$	34.45
Outstanding at March 31, 2013	2,415		$	27.96	3.6	$	39,206
Vested and expected to vest at March 31, 2013	2,388		$	27.89	3.6	$	38,919
Exercisable at March 31, 2013	1,713		$	25.56	2.7	$	31,918

Summary of Restricted Stock Activity

The following is a summary of the Company’s restricted stock activity during fiscal year 2013:

	Number of Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Non-vested at March 31, 2012	815		$	33.37
Restricted stock granted	584		$	32.22
Restricted stock vested	(254	)	$	31.24
Restricted stock forfeited	(120	)	$	32.59
Non-vested at March 31, 2013	1,025		$	33.34

Valuation Assumptions

The Company estimates the fair value of stock options and ESPP shares using a Black-Scholes option valuation model.  At the date of grant, the Company estimated the fair value of each stock option grant and purchase right granted under the ESPP using the following weighted average assumptions:

	Employee Stock Options									ESPP
Fiscal Year Ended March 31,	2013			2012			2011			2013			2012			2011
Expected volatility	41.8		%	45.3		%	45.7		%	32.4		%	37.3		%	38.7		%
Risk-free interest rate	0.6		%	1.0		%	1.4		%	0.1		%	0.1		%	0.2		%
Expected dividends	1.2		%	0.6		%	0.6		%	1.0		%	0.6		%	0.6		%
Expected life (in years)	4.3			4.0			4.2			0.5			0.5			0.5
Weighted-average grant date fair value	$	10.31		$	12.06		$	11.92		$	9.00		$	8.69		$	8.67