Note 3. Stock-Based Compensation

The Company accounts for all share-based payments in accordance with ASC Topic 718, "Compensation—Stock Compensation" ("ASC 718"). Stock‑based compensation expense included in operating expenses for the thirteen and twenty-six-week periods ended March 3, 2018 and March 4, 2017 was as follows:


	Thirteen Weeks Ended				Twenty-Six Weeks Ended
	March 3,		March 4,		March 3,		March 4,
	2018		2017		2018		2017
Stock options	$	1,128	$	1,075	$	2,322	$	2,187
Restricted share awards		670		1,012		1,572		2,334
Restricted stock units		1,821		1,233		3,575		2,275
Associate Stock Purchase Plan		76		67		120		129
Total		3,695		3,387		7,589		6,925
Deferred income tax benefit		(1,083)		(1,288)		(2,224)		(2,632)
Stock-based compensation expense, net	$	2,612	$	2,099	$	5,365	$	4,293

Stock options

The fair value of each option grant is estimated on the date of grant using the Black‑Scholes option pricing model with the following assumptions:


	Twenty-Six Weeks Ended
	March 3,		March 4,
	2018		2017
Expected life (in years)	4.0		4.1
Risk-free interest rate	1.87	%	1.16	%
Expected volatility	22.13	%	20.50	%
Expected dividend yield	2.30	%	2.40	%
Weighted-average grant-date fair value	$12.25		$9.29

A summary of the Company’s stock option activity for the twenty-six-week period ended March 3, 2018 is as follows:


	Options	Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding on September 2, 2017	1,743	$	70.88
Granted	436		79.60
Exercised	(232)		70.80
Canceled/Forfeited	(31)		72.68
Outstanding on March 3, 2018	1,916	$	72.85	4.8	$	26,947
Exercisable on March 3, 2018	764	$	73.60	3.6	$	10,167

The unrecognized share‑based compensation cost related to stock option expense at March 3, 2018 was $9,912 and will be recognized over a weighted average period of 2.6 years. The total intrinsic value of options exercised, which represents the difference between the exercise price and market value of common stock measured at each individual exercise date, during the twenty-six-week periods ended March 3, 2018 and March 4, 2017 was $5,283 and $9,100, respectively.

Restricted share awards

A summary of the non‑vested restricted share award (“RSA”) activity under the Company’s 2005 Omnibus Incentive Plan and 2015 Omnibus Incentive Plan for the twenty-six-week period ended March 3, 2018 is as follows:


	Shares	Weighted-Average Grant-Date Fair Value
Non-vested restricted share awards at September 2, 2017	160	$	80.49
Granted	—		—
Vested	(88)		79.36
Canceled/Forfeited	(3)		82.27
Non-vested restricted share awards at March 3, 2018	69	$	81.75

The fair value of each RSA is the closing stock price on the New York Stock Exchange of the Company’s Class A common stock on the date of grant. Upon vesting, a portion of the RSA award may be withheld to satisfy the statutory income tax withholding obligation. The remaining RSAs will be settled in shares of the Company’s Class A common stock when vested. The unrecognized compensation cost related to RSAs at March 3, 2018 was $3,259 and will be recognized over a weighted average period of 1.4 years.

Restricted stock units

A summary of the Company’s non-vested Restricted Stock Unit (“RSU”) award activity for the twenty-six-week period ended March 3, 2018 is as follows:


	Shares	Weighted-Average Grant-Date Fair Value
Non-vested restricted stock unit awards at September 2, 2017	313	$	66.66
Granted	166		81.00
Vested	(78)		66.60
Canceled/Forfeited	(13)		71.56
Non-vested restricted stock unit awards at March 3, 2018	388	$	72.65

The fair value of each RSU is the closing stock price on the New York Stock Exchange of the Company’s Class A common stock on the date of grant. Upon vesting, a portion of the RSU award may be withheld to satisfy the statutory income tax withholding obligation. The remaining RSUs will be settled in shares of the Company’s Class A common stock when vested. These awards accrue dividend equivalents on outstanding units (in the form of additional stock units) based on dividends declared on the Company’s Class A common stock and these dividend equivalents convert to unrestricted common stock on the vesting dates of the underlying RSUs. The dividend equivalents are not included in the RSU table above. The unrecognized compensation cost related to the RSUs at March 3, 2018 was $22,955 and is expected to be recognized over a weighted average period of 3.7 years.