STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Dec. 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 included in the condensed consolidated statements of operations:

	Three Months Ended						Nine Months Ended
	December 31,						December 31,
(in thousands)	2013			2012			2013			2012
Cost of revenues	$	686		$	507		$	1,859		$	1,629
Research, development and engineering	1,688			1,336			4,708			3,715
Selling, general and administrative	3,669			2,848			10,429			8,829
Stock-based compensation included in operating expenses	5,357			4,184			15,137			12,544
Total stock-based compensation	6,043			4,691			16,996			14,173
Income tax benefit	(1,788		)	(1,342		)	(5,063		)	(4,256		)
Total stock-based compensation, net of tax	$	4,255		$	3,349		$	11,933		$	9,917

Summary of Stock Option Activity

The following is a summary of the Company’s stock option activity during the nine months ended December 31, 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, 2013	2,415		$	27.96
Options granted	297		$	44.75
Options exercised	(702	)	$	24.27
Options forfeited or expired	(13	)	$	33.28
Outstanding at December 31, 2013	1,997		$	31.71	4.2	$	29,100
Vested and expected to vest at December 31, 2013	1,952		$	31.52	4.1	$	28,834
Exercisable at December 31, 2013	1,364		$	28.40	3.4	$	24,373

Summary of Restricted Stock Activity

Restricted stock consists of awards of restricted stock and restricted stock units ("RSUs"). The following is a summary of the Company’s restricted stock activity during the nine months ended December 31, 2013:

	Number of Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Non-vested at March 31, 2013	1,025		$	33.34
Restricted stock granted	570		$	46.09
Restricted stock vested	(373	)	$	33.09
Restricted stock forfeited	(36	)	$	37.07
Non-vested at December 31, 2013	1,186		$	39.43

Valuation Assumptions

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:

	Three Months Ended						Nine Months Ended
	December 31,						December 31,
Employee Stock Options	2013			2012			2013			2012
Expected volatility	30.1		%	41.2		%	32.2		%	41.8		%
Risk-free interest rate	1.1		%	0.6		%	0.9		%	0.6		%
Expected dividend yield	0.9		%	1.2		%	0.9		%	1.2		%
Expected life (in years)	4.2			4.3			4.2			4.3
Weighted-average grant date fair value	$	10.15		$	10.10		$	11.15		$	10.31
ESPP (1)
Expected volatility							24.9		%	38.4		%
Risk-free interest rate							0.1		%	0.1		%
Expected dividend yield							0.9		%	1.1		%
Expected life (in years)							0.5			0.5
Weighted-average grant date fair value							$	9.58		$	8.95

⁽¹⁾No purchase rights were granted under the ESPP during the three months ended December 31, 2013 or 2012.