STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Dec. 31, 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						Nine Months Ended
	December 31,						December 31,
(in thousands)	2011			2010			2011			2010
Cost of revenues	$	559		$	574		$	1,664		$	1,672
Research, development and engineering	953			958			2,928			2,862
Selling, general and administrative	3,067			2,644			8,675			7,431
Stock-based compensation expense included in operating expenses	4,020			3,602			11,603			10,293
Total stock-based compensation expense	4,579			4,176			13,267			11,965
Income tax benefit	(1,448		)	(1,298		)	(4,172		)	(3,644		)
Total stock-based compensation expense, net of tax	$	3,131		$	2,878		$	9,095		$	8,321

Summary of Stock Option Activity [Table Text Block]

The following is a summary of the Company’s stock option activity during the nine months ended December 31, 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	613		$	34.75
Options exercised	(1,301	)	$	20.82
Options forfeited or expired	(796	)	$	39.03
Outstanding at December 31, 2011	3,876		$	25.86	3.6	$	38,710
Vested and expected to vest at December 31, 2011	3,780		$	25.68	3.6	$	38,443
Exercisable at December 31, 2011	2,775		$	23.60	2.7	$	33,850

Summary of Restricted Stock Activity [Table Text Block]

The following is a summary of the Company’s restricted stock activity during the nine months ended December 31, 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	(192	)	$	27.46
Restricted stock forfeited	(50	)	$	30.02
Unvested at December 31, 2011	836		$	33.29

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						Nine Months Ended
	December 31,						December 31,
Employee Stock Options	2011			2010			2011			2010
Expected volatility	48.1		%	45.3		%	45.6		%	45.9		%
Risk-free interest rate	0.6		%	0.9		%	1.1		%	1.4		%
Expected dividends	0.6		%	0.6		%	0.6		%	0.6		%
Expected life (in years)	4.0			4.2			4.0			4.2
Weighted-average grant date fair value	$	11.86		$	12.88		$	12.08		$	11.86
ESPP
Expected volatility							38.7		%	41.8		%
Risk-free interest rate							0.1		%	0.2		%
Expected dividends							0.6		%	0.7		%
Expected life (in years)							0.5			0.5
Weighted-average grant date fair value							$	8.00		$	8.02