Stock-Based Compensation (Tables)

6 Months Ended

Sep. 30, 2014

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

Schedule of Assumptions Used

The fair values of the options and employee stock purchase rights granted are estimated as of the grant date using the Black-Scholes option-pricing model with the following weighted-average assumptions:

	Employee Stock Purchase Rights
	Three Months Ended September 30,
	2014			2013
Expected life (years)	0.5			0.5
Risk-free interest rate	0.1		%	0.1		%
Volatility	57		%	57		%
Dividend yield	—			—
Weighted average fair value	$	2.57		$	3.67

The Company did not grant options during the three months ended September 30, 2014 and 2013.

	Options				Employee Stock Purchase Rights
	Six months ended September 30,				Six months ended September 30,
	2014	2013			2014			2013
Expected life (years)	*	4.4			0.5			0.5
Risk-free interest rate	*	0.6		%	0.1		%	0.1		%
Volatility	*	49		%	57		%	57		%
Dividend yield	*	—		%	—		%	—		%
Weighted average fair value	*	$	2.95		$	2.57		$	3.67

* The Company did not grant options during the six months ended September 30, 2014.

Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units

The following table summarizes stock-based compensation expense related to stock options and RSUs (in thousands):

	Three Months Ended					Six Months Ended
	September 30,					September 30,
	2014		2013			2014		2013
Stock-based compensation expense by type of grant:
Stock options	$	292	$	737		$	706	$	1,339
Restricted stock units	3,936		3,099			8,720		6,223
	4,228		3,836			9,426		7,562
Stock-based compensation expensed from (capitalized to) inventory	2		(2		)	20		(14		)
Total stock-based compensation expense	$	4,230	$	3,834		$	9,446	$	7,548

Summary of Stock-Based Compensation Expense

The following table summarizes stock-based compensation expense as it relates to the Company’s Condensed Consolidated Statement of Operations (in thousands):

	Three Months Ended					Six Months Ended
	September 30,					September 30,
	2014		2013			2014		2013
Stock-based compensation expense by cost centers:
Cost of revenues	$	100	$	127		$	129	$	235
Research and development	2,776		1,524			6,047		3,322
Selling, general and administrative	1,352		2,185			3,250		4,005
	$	4,228	$	3,836		$	9,426	$	7,562
Stock-based compensation expensed from (capitalized to) inventory	2		(2		)	20		(14		)
Total stock-based compensation expense	$	4,230	$	3,834		$	9,446	$	7,548