The Company’s Amended and Restated 2017 Incentive Stock Plan (the “2017 Plan”) authorizes the Compensation Committee of the Board of Directors to issue up to 5,126,950 shares of various stock awards including stock options, performance-based restricted stock units, restricted stock units and other forms of equity-based awards to key employees and directors. Options granted and outstanding vest over the requisite service period and expire ten years from the date of grant. The following tables summarize stock option activity in the past three years.

Stock compensation expense was approximately $1,715, $4,257 and $3,626 for the years ended December 31, 2019, 2018 and 2017, respectively, and are included in general and administrative expenses. During 2019, the Company reversed previously recognized compensation expense of $2,031 related to the resignation of the Company’s President and Chief Executive Officer effective October 25, 2019. Total unrecognized compensation cost related to non-vested share based compensation arrangements at December 31, 2019 was approximately $3,353 which will be recognized over the next three years, as such compensation is earned.

Year	Options		Exercise Price
2019		235,474	$	18.54
2018		255,072	$	21.30
2017		397,759	$	14.30

Options exercised in 2019, 2018 and 2017 were as follows:

Year	Options		Exercise Price
2019		221,695	$11.62 to $14.30
2018		191,169	$9.97 to $20.93
2017		375,292	$9.97 to $20.93

In addition, options totaling 268,545, 86,411 and 218,130 expired or were forfeited during the years ended December 31, 2019, 2018 and 2017, respectively.

Options outstanding and exercisable at December 31, 2019, 2018 and 2017 were as follows:

Year	Outstanding		Range of Exercise Prices	Exercisable		Weighted Average Exercise Price
2019		710,893	$10.10 to $21.30		486,382	$	17.31
2018		965,659	$10.10 to $21.30		521,202	$	16.08
2017		988,167	$9.97 to $20.93		539,993	$	16.23

The fair value of options granted is estimated using an option pricing model based on the assumptions set forth in the following table. The Company uses historical data to estimate employee exercise and departure behavior. The risk free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant and through the expected term. The dividend yield rate is based on the Company’s historical dividend yield. The expected volatility is derived from historical volatility of the Company’s shares and those of similar companies measured against the market as a whole. The Company used the binomial lattice option pricing model based on the assumptions set forth in the following table.

	2019			2018			2017
Risk free interest rate		2.70	%		2.90	%		2.50	%
Expected dividend yield		2.76	%		2.50	%		3.80	%
Expected life of award (years)		6.17			4.00			4.10
Expected volatility		44.89	%		42.50	%		50.00	%
Fair value per option	$	5.78		$	6.30		$	4.47

The following table provides a summary of stock option activity for the period ended December 31, 2019:

	Shares			Average Exercise Price		Weighted Average Life (in Years)
Outstanding at December 31, 2018		965,659		$	16.69
Options granted		235,474			18.54
Options exercised		(221,695	)		13.26
Canceled or forfeited		(268,545	)		18.36
Expired		—			—
Outstanding at December 31, 2019		710,893			17.75		5.96
Exercisable at December 31, 2019		486,382		$	17.31		4.72

The intrinsic value of a stock option is the amount by which the market value of the underlying stock exceeds the exercise price of the option. The intrinsic value of stock options exercised in 2019, 2018 and 2017 was $732, $1,745 and $2,813, respectively.

The following table provides a summary of restricted stock units, including performance-based restricted stock units, and restricted stock activity for the year ended December 31, 2019:

	Shares			Average Grant-Date Fair Value
Unvested shares at December 31, 2018		423,795
Granted		253,318		$	18.14
Vested		(151,823	)		15.35
Forfeited		(256,023	)		16.95
Unvested shares at December 31, 2019		269,267

Restricted stock units are rights to receive shares of common stock, subject to forfeiture and other restrictions, which vest over a one or three year period. Restricted stock units are considered to be non-vested shares under the accounting guidance for share-based payment and are not reflected as issued and outstanding shares until the restrictions lapse. At that time, the shares are released to the grantee and the Company records the issuance of the shares. Restricted stock awards are valued based on the market price of the underlying shares on the grant date. Compensation expense is recognized on a straight-line basis over the requisite service period. At December 31, 2019, restricted stock awards had vesting periods through October 2022.

Included in the December 31, 2019 unvested shares are 112,541 performance-based restricted stock units. The fair value of these awards is calculated using the market price of the underlying common stock on the date of grant. In determining fair value per share, the Company does not take into account performance-based vesting requirements. For these awards, the performance-based vesting requirements determines the number of shares that ultimately vest, which can vary from 0% to 200% of target depending on the level of achievement of established performance criteria. Compensation expense is recognized over the requisite service period subject to adjustment based on the probable number of shares expected to vest under the performance condition.