Stockholders' Equity and Stock-Based Compensation (Tables)

6 Months Ended

Jun. 29, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Employee Stock Purchase Plan Assumptions

	Three Months Ended		Six Months Ended
	June 29, 2019	June 30, 2018	June 29, 2019	June 30, 2018
Employee Stock Purchase Plan:
Expected life	0.5 years	0.5 years	0.5 years	0.5 years
Volatility	41.3%	27.2%	39.1%	37.2%
Risk free interest rate	2.51%	1.61%	1.86%	0.91%
Dividends	—	—	—	—

Summary of Activity of Stock Options

A summary of activity of stock options during the six months ended June 29, 2019 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 29, 2018		83,394		$	15.80		1.19	$	988
Exercised		(70,100	)		15.72
Cancelled		—		—
Outstanding at June 29, 2019		13,294			16.19		1.05		246
Exercisable at June 29, 2019		13,294		$	16.19		1.05	$	246

Summary of Activity for RSUs

A summary of activity for RSUs during the six months ended June 29, 2019 is as follows:

Summary of activity for RSUs	Number of RSUs			Weighted Average Fair Value
Outstanding RSUs as of December 29, 2018		769,003		$	31.39
Granted		339,822			28.68
Released		(303,127	)		28.47
Cancelled		(45,576	)		32.36
Outstanding RSUs as of June 29, 2019		760,122		$	31.28

Summary of Activity for PSUs

A summary of activity for PSUs for the six months ended June 29, 2019 is as follows:

Summary of activity for PSUs	Number of PSUs			Weighted Average Fair Value
Outstanding PSUs as of December 29, 2018		112,163		$	22.37
Granted		43,429			19.09
Released		(16,066	)		25.09
Cancelled		(1,138	)		26.75
Outstanding PSUs as of June 29, 2019		138,388		$	20.99

PSUs Valuation Assumptions

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

	2019 Award		2018 Award
Grant Date Fair Value Per Share	$13.12-$23.75		$20.73-$25.18
Weighted-average assumptions/inputs:
Expected Dividend		—		—
Range of risk-free interest rates	2.45%		2.39%-2.63%
Range of expected volatilities for peer group	22%-63%		22%-66%

Stock-based Compensation Expense

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):

	Three Months Ended				Six Months Ended
	June 29, 2019		June 30, 2018		June 29, 2019		June 30, 2018
Cost of products	$	272	$	133	$	532	$	231
Cost of service		209		186		394		341
Research and development		739		506		1,511		983
Selling		740		737		1,544		1,270
General and administrative		1,240		1,117		2,333		2,192
Total stock-based compensation expense related to employee stock options and employee stock purchases	$	3,200	$	2,679	$	6,314	$	5,017