Stockholders' Equity and Stock-Based Compensation (Tables)

3 Months Ended

Mar. 26, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Employee stock purchase plan assumptions

	March 26, 2016			March 28, 2015
Employee Stock Purchase Plan:
Expected life	0.5 years			0.5 years
Volatility		39.1	%		37.2	%
Risk free interest rate		0.49	%		0.11	%
Dividends		—			—

Stock option plans activity

A summary of activity of stock options during the three months ended March 26, 2016 is as follows:

	Number of Shares Outstanding (Options)			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (inThousands)
Options
Outstanding at December 26, 2015		1,051,867		$	14.60		2.46	$	1,916
Exercised		(5,846	)	$	13.74
Cancelled		(137,633	)	$	16.26
Outstanding at March 26, 2016		908,388		$	14.36		2.60	$	1,269
Exercisable at March 26, 2016		799,365		$	14.09		2.34	$	1,265

Summary of activity for RSUs

A summary of activity for RSUs is as follows:

Summary of activity for RSUs	Number of RSUs			Weighted Average Fair Value
Outstanding RSUs as of December 26, 2015		713,243		$	15.99
Granted		137,718		$	13.29
Released		(108,305	)	$	17.13
Cancelled		(14,348	)	$	15.48
Outstanding RSUs as of March 26, 2016		728,308		$	15.32

Summary of activity for PSUs

A summary of activity for PSUs is as follows:

Summary of activity for PSUs	Number of PSUs			Weighted Average Fair Value
Outstanding PSUs as of December 26, 2015		60,000		$	18.35
Granted		67,500		$	12.78
Released		(13,333	)	$	18.04
Cancelled		(6,667	)	$	18.04
Outstanding PSUs as of March 26, 2016		107,500		$	14.91

PSUs valuation assumptions

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

	2016 Award		2015 Award
Grant Date Fair Value Per Share	$	12.78	$	18.35
Weighted-average assumptions/inputs:
Expected Dividend		—		—
Range of risk-free interest rates		0.92%	0.25%-1.1%
Range of expected volatilities for peer group	22%-93%		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 26, 2016		March 28, 2015
Cost of products	$	67	$	73
Cost of service		104		46
Research and development		285		280
Selling		492		500
General and administrative		741		672
Total stock-based compensation expense related to employee    stock options and employee stock purchases	$	1,689	$	1,571