Stock-Based Employee Compensation (Tables)

3 Months Ended

Jun. 28, 2015

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

Compensation Expense

The following table summarizes stock-based compensation expense by line items appearing in the Company’s Condensed Consolidated Statement of Operations:

	Three Months Ended
(in thousands)	June 28, 2015			June 29, 2014
Cost of revenue	$	683		$	316
Research and development	3,632			2,521
Selling, general and administrative	3,552			2,122
Discontinued operations	(32		)	54
Total stock-based compensation expense	$	7,835		$	5,013

Stock Option Activity

The following is a summary of the Company's stock option activity and related weighted average exercise prices for each category:

	Three Months Ended June 28, 2015
(shares in thousands)	Shares		Price
Beginning stock options outstanding	3,680		$	7.71
Granted	420		21.85
Exercised (1)	(467	)	7.19
Canceled	(33	)	7.45
Ending stock options outstanding	3,600		$	9.44
Ending stock options exercisable	2,177		$	7.12

(1) Upon exercise, the Company issues new shares of common stock.

Nonvested Restricted Stock Units Activity

The following table summarizes the Company's restricted stock unit activity and related weighted-average exercise prices for each category for the three months ended June 28, 2015:

	Three Months Ended June 28, 2015
(shares in thousands)	Shares		Weighted-average grant date fair value per share
Beginning RSUs outstanding	3,457		$	10.58
Granted	1,381		21.96
Released	(915	)	9.13
Forfeited	(159	)	12.32
Ending RSUs outstanding	3,764		$	15.04

Nonvested Performance-based Units Activity

The following table summarizes the Company's performance stock unit activity and related weighted-average exercise prices for each category for the three months ended June 28, 2015:

	Three Months Ended June 28, 2015
(shares in thousands)	Shares		Weighted-average grant date fair value per share
Beginning PSUs outstanding	517		$	8.06
Granted	3		8.50
Released	(89	)	7.77
Forfeited	(137	)	8.55
Ending PSUs outstanding	294		$	7.92

Fair Value Assumptions

The following weighted average assumptions were used to calculate the fair value of the market-based equity award using a Monte Carlo simulation model:

	June 15, 2015			June 15, 2014
Estimated fair value	$	33.08		$	21.00
Expected volatility	41.22		%	34.60		%
Expected term (in years)	1.80			1.80
Risk-free interest rate	0.65		%	0.38		%
Dividend yield	—		%	—		%

Employee Stock Purchase Plan Activity

Activity under the Company's ESPP for the three months ended June 28, 2015 is summarized in the following table:

(in thousands, except per share amounts)
Number of shares issued	230
Average issuance price	$	16.82
Number of shares available at June 28, 2015	4,148