Stock-Based Compensation (Tables)

6 Months Ended

Sep. 30, 2013

Summary of Stock-Based Compensation Expense

The Company accounts for its stock-based compensation at fair value. The following table summarizes stock-based compensation expense by financial statement line item for the three and six months ended September 30, 2013 and 2012 (in thousands):

	Three months ended September 30,					Six months ended September 30,
	2013		2012			2013			2012
Cost of revenues	$	224	$	213	$		429	$		383
Research and development		585		591			1,159			1,154
Selling, general and administrative		1,343		1,240			2,699			2,502
Total	$	2,152	$	2,044	$		4,287	$		4,039

Schedule of Weighted Average Assumptions used in Black-Scholes Valuation Model for Stock Options Granted

The weighted-average assumptions used in the Black-Scholes valuation model for stock options granted during the three and six months ended September 30, 2013 and 2012 are as follows:

	Three months ended September 30,						Six months ended September 30,
	2013			2012			2013			2012
Expected volatility		75.4	%		71.9	%		75.1	%		71.9	%
Risk-free interest rate		1.7	%		0.8	%		1.7	%		0.9	%
Expected life (years)		5.8			5.9			5.9			5.9
Dividend yield		None			None			None			None