On May 16, 2018, our shareholders approved our 2018 Stock Option and Stock Incentive Plan (the “2018 Plan” or the “Plan”), which supersedes our 2008 Stock Option and Stock Incentive Plan. All future stock compensation grants will be issued under the 2018 Plan. Under the terms of the Plan, our Board of Directors may grant up to 1,200,000 shares of common stock in the form of shares of restricted stock, restricted stock units, stock appreciation rights and stock options or combinations thereof to officers, directors, employees, important consultants and advisors. Grants under the Plan must be made within ten years of the date the Plan was approved. Stock options are exercisable upon the terms set forth in each grant agreement approved by the Board of Directors, but in no event more than ten years from the date of grant. Restricted stock and restricted stock units vest in accordance with the terms set forth in each applicable award agreement approved by our Board of Directors. At March 30, 2019, 1,085,954 shares were available for grant under the 2018 Plan.

We grant restricted stock to certain employees and members of our Board of Directors. Vesting of restricted stock is conditional based on continued employment or service for a specified period and, in certain circumstances, the attainment of performance goals. We retain the restricted stock, and any dividends paid thereon, until the vesting conditions have been met. For time-based restricted stock awards, compensation cost related to the stock is recognized on a straight-line basis over the vesting period and is calculated using the closing price per share of our common stock on the grant date. For performance-based restricted stock awards tied to growth in pre-tax income, compensation cost related to the stock is recognized over the performance period and is calculated using the closing price per share of our common stock on the grant date and an estimate of the probable outcome of the performance conditions. In 2019, we introduced performance shares that vest based on our total shareholder return ranking relative to the S&P Midcap 400 Growth Index over a three-year performance period. For performance-based restricted stock awards tied to total shareholder return, compensation cost related to the stock is recognized on a straight-line basis over the performance period and is calculated using the simulated fair value per share of our common stock based on the application of a Monte Carlo simulation model. Compensation cost related to restricted stock was $0.7 million for the thirteen weeks ended March 30, 2019 and March 31, 2018 and is classified as selling, general and administrative expense in the Consolidated Statements of Income.

The following table summarizes our restricted stock activity for the thirteen weeks ended March 30, 2019:

	Shares			Weighted Average Price
Balance at December 29, 2018		170,737		$	63.94
Granted		74,879		$	82.11
Vested		(24,849	)	$	50.81
Cancelled		(26,972	)	$	48.23
Balance at March 30, 2019		193,795		$	74.83

As of March 30, 2019, there was $7.9 million of unrecognized compensation cost related to unvested restricted stock, which is expected to be recognized over a weighted-average period of approximately 2.9 years.

Cash flows resulting from tax deductions in excess of the tax effect of compensation cost recognized in the financial statements are classified as operating cash flows. The excess tax benefit generated from restricted stock which vested was $0.2 million and $0.1 million in the thirteen weeks ended March 30, 2019 and March 31, 2018, respectively, and was credited to income tax expense.

We grant stock options to certain employees. We expense the grant-date fair value of stock options. Compensation cost is recognized on a straight-line basis over the vesting period for which related services are performed. The compensation cost charged against income was $0.2 million and $0.1 million for the thirteen weeks ended March 30, 2019 and March 31, 2018, respectively. The compensation costs were classified as selling, general and administrative expense in the Consolidated Statements of Income. No cost was capitalized during the thirteen weeks ended March 30, 2019.

We use the Black-Scholes option valuation model to estimate the fair value of stock options granted. Expected volatility and expected dividend yield are based on the actual historical experience of our common stock. The expected life represents the period of time that options granted are expected to be outstanding and was calculated using historical option exercise data. The risk-free rate was based on a U.S. Treasury security with terms equal to the expected time of exercise as of the grant date. During the thirteen weeks ended March 30, 2019 and March 31, 2018 we granted 28,538 and 61,514 stock options, respectively.

The following table summarizes our stock option activity for the thirteen weeks ended March 30, 2019:

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Term (In years)		Aggregate Intrinsic Value
Balance at December 29, 2018		188,469		$	66.14
Granted		28,538		$	82.56
Exercised		(33,228	)	$	58.81
Balance at March 30, 2019		183,779		$	70.01		4.1	$	3,321,984
Options exercisable at March 30, 2019		61,415		$	62.01		2.7	$	1,601,664

There were 33,228 options exercised during the thirteen weeks ended March 30, 2019. There were no options exercised in the thirteen weeks ended March 31, 2018. As of March 30, 2019, there was $1.9 million of unrecognized compensation cost related to non-vested stock options, which is expected to be recognized over a weighted-average period of 3.0 years.

Cash generated from stock option exercises was less than $0.1 million in the thirteen weeks ended March 30, 2019. There was no cash received from stock option exercises in the thirteen weeks ended March 31, 2018.

There was no excess tax benefit generated from stock options exercised in the thirteen weeks ended March 30, 2019 or March 31, 2018.

In May 2017, our shareholders’ approved the Dorman Products, Inc. Employee Stock Purchase Plan (the “ESPP”), which makes available 1,000,000 shares of our common stock for sale to eligible employees. There were no shares purchased under this plan in the thirteen weeks ended March 30, 2019 and March 31, 2018. During both the thirteen weeks ended March 30, 2019 and March 31, 2018, compensation cost under the Plan was less than $0.1 million.