Stock-Based Compensation (Tables)

9 Months Ended

Dec. 31, 2012

Stock-Based Compensation Recognized

The following table summarizes stock-based compensation expense by financial statement line item in the Company’s consolidated statements of operations (in thousands):

	Three Months  Ended December 31,				Nine Months  Ended December 31,
	2012		2011		2012		2011
Cost of product revenue	$	83	$	66	$	330	$	216
Research and development		333		397		1,331		1,269
Selling, general and administrative		1,520		1,310		5,238		4,419
	$	1,936	$	1,773	$	6,899	$	5,904

Components of Stock-Based Compensation

The components of stock-based compensation were as follows (in thousands):

	Three Months  Ended December 31,				Nine Months  Ended December 31,
	2012		2011		2012		2011
Stock options	$	583	$	612	$	2,135	$	2,116
Restricted stock		81		262		541		1,722
Restricted stock units		1,220		864		4,085		1,966
Employee stock purchase plan		52		35		138		100
	$	1,936	$	1,773	$	6,899	$	5,904

Summary of Stock Option Activity

The following table summarizes the stock option activity for the nine months ended December 31, 2012:

						Weighted
	Shares			Weighted		Average		Aggregate
	Underlying			Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	(in thousands)			Price		Term (years)		($000’s)
Outstanding at April 1, 2012		4,268		$	10.42		6.03
Granted		323			22.32
Exercised		(313	)		8.73
Cancelled and expired		(63	)		10.22
Outstanding at December 31, 2012		4,215		$	11.44		5.55	$	12,688
Exercisable at December 31, 2012		3,214		$	10.81		4.82	$	9,571
Options vested and expected to vest at December 31, 2012		3,985		$	11.43		5.43	$	11,825

Weighted-Average Assumptions Used to Calculate Fair Value of Options Granted

The fair value of options granted during the three and nine months ended December 31, 2012 and 2011 were calculated using the following weighted average assumptions:

	Three Months Ended						Nine Months Ended
	December 31,						December 31,
	2012			2011			2012			2011
Risk-free interest rate		0.63	%		0.92	%		0.77	%		1.49	%
Expected option life (years)		4.23			5.09			4.32			5.23
Expected volatility		58.1	%		55.1	%		56.4	%		52.7	%

Summary of Restricted Stock and Restricted Stock Units Activity

The following table summarizes the activity for the nine months ended December 31, 2012:

				Weighted Average
	Number of			Grant Date
	Shares (thousands)			Fair Value
Outstanding at April 1, 2012		871		$	15.76
Granted		397			22.32
Vested		(218	)		13.62
Forfeited		(26	)		20.27
Outstanding at December 31, 2012		1,024		$	18.64