Common Stock and Share-Based Compensation (Tables)

6 Months Ended

Jun. 27, 2020

Summary of Stock Options under Equity Plan and Non-Employee Director Plan

Information related to stock options under the Restated Employee Equity Incentive Plan and the Stock Option Plan for Non-Employee Directors is summarized as follows:

	Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (in thousands)
Outstanding at December 28, 2019		315,678		$	186.53
Granted		25,870			383.22
Forfeited		(2,595	)		241.84
Expired		—			—
Exercised		(57,926	)		120.81
Outstanding at June 27, 2020		281,027		$	217.67		6.14	$	97,280
Exercisable at June 27, 2020		92,818		$	185.56		5.11	$	35,110
Vested and expected to vest at June 27, 2020		256,784		$	216.12		6.09	$	89,287

Stock-Based Compensation Expense Included in Operating Expenses

The following table provides information regarding stock-based compensation expense included in operating expenses in the accompanying consolidated statements of comprehensive income:

	Thirteen weeks ended				Twenty-six weeks ended
	June 27, 2020		June 29, 2019		June 27, 2020		June 29, 2019
	(in thousands)				(in thousands)
Amounts included in advertising, promotional and selling expenses	$	1,147	$	1,121	$	1,852	$	1,598
Amounts included in general and administrative expenses		3,390		2,624		5,251		4,212
Total stock-based compensation expense	$	4,537	$	3,745	$	7,103	$	5,810

Weighted Average Assumptions used to Estimate Fair Value of Stock Options

Weighted average assumptions used to estimate fair values of stock options on the date of grants are as follows:

	2020
Expected Volatility		32.6	%
Risk-free interest rate		1.09	%
Expected Dividends		0.0	%
Exercise factor		2.12 times
Discount for post-vesting restrictions		0.0	%

Summary of Vesting Activities of Shares Issued Under Investment Share Program and Restricted Stock Awards

The following table summarizes vesting activities of shares issued under the investment share program and restricted stock awards:

	Number of Shares			Weighted Average Fair Value
Non-vested at December 28, 2019		122,142		$	213.52
Granted		40,316			325.12
Vested		(45,169	)		213.12
Forfeited		(3,318	)		241.05
Non-vested at June 27, 2020		113,971		$	252.36