Stock-Based Compensation

3 Months Ended

Jun. 30, 2015

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

Stock-based compensation cost is measured at the grant date based on the fair value of the award. The fair value of RSUs is estimated using the Company's stock price on the grant date. The fair value of options and employee stock purchase rights is estimated using the Black-Scholes model on the grant date. The Black-Scholes model determines the fair value of share-based payment awards based on assumptions including the Company's stock price on the date of grant, volatility over the term of the awards, actual and projected employee stock option exercise behaviors and risk free interest rate. The MSUs were valued using the Monte Carlo pricing model, which uses the Company's stock price, the Index value, expected volatilities of the Company's stock price and the Index, correlation coefficients and risk free interest rates to determine the fair value.

The Company did not grant options or employee stock purchase rights during the three months ended June 30, 2015 and 2014.

The weighted average grant-date fair value per share of the RSUs awarded was $6.09 and $8.85 during the three months ended June 30, 2015 and 2014, respectively. The weighted average grant-date fair value per share was calculated based on the fair market value of the Company’s common stock on the respective grant dates.

During the first quarter of fiscal 2016, the Company revised the estimated forfeiture rate used in determining the amount of stock-based compensation from 6.1% to 7.4%, which the Company believes is indicative of the rate it will experience during the remaining vesting period of currently outstanding unvested grants.

The following tables summarize the allocation of the stock-based compensation expense (in thousands):



Stock-based compensation expense by type of grant:	Three months ended June 30,
	2015			2014
Stock options and stock purchase rights	$	207		$	414
RSUs	5,897			4,784
	6,104			5,198
Stock-based compensation (capitalized to) expensed from inventory	(12		)	18
Total stock-based compensation expense	$	6,092		$	5,216



Stock-based compensation expense by cost centers:	Three months ended June 30,
	2015			2014
Cost of revenues	$	105		$	29
Research and development	4,060			3,271
Selling, general and administrative	1,939			1,898
	$	6,104		$	5,198
Stock-based compensation (capitalized to) expensed from inventory	(12		)	18
Total stock-based compensation expense	$	6,092		$	5,216

As of June 30, 2015, the amount of unrecognized stock-based compensation cost, net of estimated forfeitures, related to unvested stock options and unvested RSUs was $25.1 million which will be recognized over a weighted average period of 1.3 years.