Stock-Based Compensation Expense (Tables)

6 Months Ended

Jun. 29, 2014

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 June 29, 2014:

	Shares (in thousands)		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2013	6,138		$	15.65
Granted	1,311		38.89
Exercised	(635	)	14.20
Forfeited or expired	(138	)	19.55
Outstanding as of June 29, 2014	6,676		$	20.27	7.3	$	118,374
Exercisable as of June 29, 2014	2,744		$	13.13	5.7	$	67,421
Options vested or expected to vest at   June 29, 2014 (1)	6,026		$	19.44	7.1	$	111,631

 (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
	June 29, 2014		June 30, 2013		June 29, 2014		June 30, 2013
Risk-free rate	2.7	%	2.0	%	2.7	%	2.0	%
Expected dividend yield	—	%	—	%	—	%	—	%
Expected volatility	41	%	42	%	41	%	42	%
Expected term (in years)	5.4		5.9		5.4		5.9

Nonvested Restricted Stock Shares Activity

The following table summarizes the Company's restricted stock award activity for the six-month period ended June 29, 2014:

	Shares (in thousands)	Weighted-Average Exercise Price		Aggregate Intrinsic Value (in thousands)
Nonvested as of December 31, 2013	—	$	—
Granted	20	34.05
Vested	—	—
Forfeited or expired	—	—
Nonvested as of June 29, 2014	20	$	34.05	$	73

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

The following table details 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
	June 29, 2014		June 30, 2013		June 29, 2014		June 30, 2013
Product cost of revenue	$	268	$	177	$	553	$	404
Service cost of revenue	44		47		107		110
Research, development, and engineering	988		650		2,044		1,463
Selling, general, and administrative	2,656		1,907		5,256		4,102
	$	3,956	$	2,781	$	7,960	$	6,079