STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Sep. 30, 2011

Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]

Stock-Based Compensation Expense Included in Statements of Operations [Table Text Block]

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

	Three Months Ended						Six Months Ended
	September 30,						September 30,
(in thousands)	2011			2010			2011			2010
Cost of revenues	$	559		$	565		$	1,105		$	1,098
Research, development and engineering	1,028			967			1,975			1,904
Selling, general and administrative	2,921			2,480			5,608			4,787
Stock-based compensation expense included in operating expenses	3,949			3,447			7,583			6,691
Total stock-based compensation expense	4,508			4,012			8,688			7,789
Income tax benefit	(1,441		)	(1,305		)	(2,723		)	(2,346		)
Total stock-based compensation expense, net of tax	$	3,067		$	2,707		$	5,965		$	5,443

Summary of Stock Option Activity [Table Text Block]

The following is a summary of the Company’s stock option activity during the six months ended September 30, 2011:

	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, 2011	5,360		$	25.58
Options granted	424		$	35.54
Options exercised	(795	)	$	20.95
Options forfeited or expired	(703	)	$	39.33
Outstanding at September 30, 2011	4,286		$	25.17	3.6	$	21,669
Vested and expected to vest at September 30, 2011	4,186		$	24.99	3.5	$	21,573
Exercisable at September 30, 2011	3,119		$	23.18	2.7	$	19,052

Summary of Restricted Stock Activity [Table Text Block]

The following is a summary of the Company’s restricted stock activity during the six months ended September 30, 2011:

	Number of Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Unvested at March 31, 2011	688		$	29.52
Restricted stock granted	390		$	36.36
Restricted stock vested	(68	)	$	27.90
Restricted stock forfeited	(28	)	$	29.64
Unvested at September 30, 2011	982		$	32.47

Valuation Assumptions [Table Text Block]

The fair value of stock options and ESPP shares granted during the respective periods is estimated on the date of grant using the following weighted average assumptions:

	Three Months Ended						Six Months Ended
	September 30,						September 30,
Employee Stock Options	2011			2010			2011			2010
Expected volatility	44.7		%	46.6		%	44.4		%	46.3		%
Risk-free interest rate	0.6		%	1.2		%	1.2		%	1.7		%
Expected dividends	0.6		%	0.7		%	0.6		%	0.7		%
Expected life (in years)	4.0			4.2			4.0			4.2
Weighted-average grant date fair value	$	10.85		$	11.14		$	12.18		$	11.22
ESPP
Expected volatility	38.7		%	41.8		%	38.7		%	41.8		%
Risk-free interest rate	0.1		%	0.2		%	0.1		%	0.2		%
Expected dividends	0.6		%	0.7		%	0.6		%	0.7		%
Expected life (in years)	0.5			0.5			0.5			0.5
Weighted-average grant date fair value	$	8.00		$	8.02		$	8.00		$	8.02