Stock-Based Compensation Expense (Tables)

6 Months Ended

Jul. 03, 2016

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

Summary of Stock Option Activity

The following table summarizes the Company’s stock option activity for the six-month period ended July 3, 2016:

	Shares (in thousands)		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2015	6,644		$	28.27
Granted	1,687		33.55
Exercised	(461	)	18.88
Forfeited or expired	(125	)	37.06
Outstanding as of July 3, 2016	7,745		$	29.84	7.3	$	102,823
Exercisable as of July 3, 2016	3,408		$	21.92	5.6	$	72,213
Options vested or expected to vest as of July 3, 2016 (1)	7,025		$	29.13	7.2	$	98,222

 (1) In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest are calculated by applying an estimated forfeiture rate to the unvested options.

Weighted-Average Assumptions Used in Estimating Fair Values of Stock Options Granted

The fair values of stock options granted in each period presented were estimated using the following weighted-average assumptions:

	Three-months Ended				Six-months Ended
	July 3, 2016		July 5, 2015		July 3, 2016		July 5, 2015
Risk-free rate	1.7	%	2.1	%	1.7	%	2.1	%
Expected dividend yield	0.84	%	1.25	%	0.84	%	1.25	%
Expected volatility	41	%	40	%	41	%	40	%
Expected term (in years)	5.4		5.4		5.5		5.4

Nonvested Restricted Stock Shares Activity

The following table summarizes the Company's restricted stock activity for the six-month period ended July 3, 2016:

	Shares (in thousands)	Weighted-Average Grant Fair Value		Aggregate Intrinsic Value (in thousands)(1)
Nonvested as of December 31, 2015	20	$	34.05
Granted	—	—
Vested	—	—
Forfeited or expired	—	—
Nonvested as of July 3, 2016	20	$	34.05	$	862

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The following table presents the stock-based compensation expense by caption for each period presented on the Consolidated Statements of Operations (in thousands):

	Three-months Ended				Six-months Ended
	July 3, 2016		July 5, 2015		July 3, 2016		July 5, 2015
Cost of revenue	$	229	$	349	$	522	$	816
Research, development, and engineering	1,397		1,153		3,576		2,967
Selling, general, and administrative	2,831		2,985		7,163		7,367
Discontinued operations	—		144		—		427
	$	4,457	$	4,631	$	11,261	$	11,577