Stockholders' Equity and Stock-Based Compensation (Tables)

3 Months Ended

Mar. 28, 2015

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

Stock options valuation assumptions

	March 28, 2015	March 29, 2014
Stock Options:
Expected life	—	4.6 years
Volatility	—	56.8%
Risk free interest rate	—	1.53%
Dividends	—	—
Employee Stock Purchase Plan:
Expected life	0.5 years	0.5 years
Volatility	37.2%	32.6%
Risk free interest rate	0.11%	1.00%
Dividends	—	—

Employee stock purchase plan valuation assumptions

	March 28, 2015	March 29, 2014
Stock Options:
Expected life	—	4.6 years
Volatility	—	56.8%
Risk free interest rate	—	1.53%
Dividends	—	—
Employee Stock Purchase Plan:
Expected life	0.5 years	0.5 years
Volatility	37.2%	32.6%
Risk free interest rate	0.11%	1.00%
Dividends	—	—

Stock option plans activity

A summary of activity of stock options during the three months ended March 28, 2015 is as follows:

	Number of Shares Outstanding (Options)		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in Thousands)
Options
Outstanding at December 27, 2014	1,382,993		$	13.92	3.41	$	4,108
Exercised	(127,814	)	11.82
Granted	—		—
Cancelled	(3,263	)	15.57
Outstanding at March 28, 2015	1,251,916		$	14.14	3.17	$	4,069
Exercisable at March 28, 2015	992,179		$	13.57	2.72	$	3,757

Summary of activity for RSUs

A summary of activity for RSUs is as follows:

RSUs	Number of RSUs		Weighted Average Fair Value
Outstanding RSUs as of December 27, 2014	563,337		$	17.90
Granted	71,533		17.92
Released	(127,096	)	17.78
Cancelled	(8,399	)	16.56
Outstanding RSUs as of March 28, 2015	499,375		$	17.96

PSUs valuation assumptions

The assumptions for the valuation of PSUs are summarized as follows:

PSUs	2015 Awards
Number of PSUs granted and outstanding as of March 28, 2015	40,000
Weighted-average assumptions/inputs:
Expected Dividend	—
Range of risk-free interest rates	0.25%-1.1%
Range of expected volatilities for peer group	23%-65%

Stock-based compensation expense for all share-based payment awards

Stock-based compensation expense for all share-based payment awards made to the Company’s employees and directors pursuant to the employee stock option and employee stock purchase plans by function were as follows (in thousands):

	March 28, 2015		March 29, 2014
Cost of products	$	73	$	61
Cost of service	46		84
Research and development	280		340
Selling	500		427
General and administrative	672		722
Total stock-based compensation expense related to employee stock options and employee stock purchases	$	1,571	$	1,634