Stock-Based Compensation (Tables)

3 Months Ended

Mar. 28, 2015

Assumptions Used to Estimate The Fair Value of The Performance-based Stock Options and Restricted Stock Units

The assumptions used to estimate the fair value of the performance-based stock options and restricted stock units under the Monte Carlo Simulation model are as follows:

	Three Months Ended
	March 28, 2015			March 29, 2014
Risk-free interest rate		0.95% - 1.48	%		—
Expected dividend yield		0	%		—
Expected option life		4 years			—
Expected volatility		44.5	%		—
Weighted-average expected volatility		44.5	%		—

Fair Value of Options Granted

For stock options granted during the three months ended March 28, 2015 and March 29, 2014 valued using the Black-Scholes option-pricing model, we used the following assumptions:

	Three Months Ended
	March 28, 2015			March 29, 2014
Risk-free interest rate		0.99% - 1.06	%		1.10	%
Expected dividend yield		0	%		0	%
Expected option life		3 years			4 years
Expected volatility		42.3	%		42.5	%
Weighted-average expected volatility		42.3	%		42.5	%

Summary of Stock Option Activity

A summary of stock option activity and weighted-average exercise prices for the three months ended March 28, 2015 follows:

	Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value as of March 28, 2015
Outstanding at January 1, 2015		898,429		$	44.40
Granted		440,553			59.66
Forfeited		(37,523	)		55.28
Exercised		(59,749	)		32.67
Outstanding at March 28, 2015		1,241,710		$	50.04		5.1	$	11,185
Options exercisable at March 28, 2015		586,671		$	42.51		3.7	$	9,660

Summary of Restricted Stock Activity

The following table summarizes the restricted stock and restricted stock unit activity and weighted average grant-date fair values for the three months ended March 28, 2015:

	Shares			Weighted-Average Grant Date Fair Value
Non-vested at January 1, 2015		13,955		$	43.57
Granted		4,109			59.97
Forfeited		(1,397	)		59.97
Vested		(469	)		55.83
Non-vested at March 28, 2015		16,198		$	47.08