(11) Stock-Based Compensation Plans

The components of stock compensation expense for the three years ended December 31, 2017 were as follows:


	2017		2016		2015
	(in thousands)
2007 Stock Incentive Plan	$	4,207	$	3,681	$	4,102
Employee Stock Purchase Plan		63		36		48
Total Stock Compensation Expense	$	4,270	$	3,717	$	4,150

The significant stock compensation plans are described below.

The 2007 Stock Incentive Plan (the “2007 Plan”) was adopted on May 24, 2007. Under this 2007 Plan, a total of 2,000,000 shares are authorized for stock based compensation available in the form of either restricted stock awards (“RSA’s”) or stock options. On May 28, 2015, the Company’s shareholders authorized an increase in the number of shares of Common Stock available for grant by 800,000 shares bringing the total to 2,800,000 shares authorized. The RSA’s are subject to service-based vesting, typically between one and four years, where a specific period of continued employment must pass before an award vests. With the modified retrospective adoption of ASU 2016-09 on January 1, 2017, the Company no longer reduces stock-based compensation by estimated forfeitures and instead accounts for forfeitures when they occur. For any vesting tranche of an award, the cumulative amount of compensation cost recognized is equal to the portion of the grant‑date fair value of the award tranche that is actually vested at that date.

As of December 31, 2017, the Company has granted 2,615,960 RSA’s under the 2007 Plan. Of this amount, 166,744 shares were cancelled and returned to the pool of shares which could be granted under the 2007 Plan resulting in a net number of 350,784 shares available as of December 31, 2017 for future issuance. The fair value of the restricted stock awards equaled the stock price at the date of grants.

The following table summarizes restricted stock acitivty under the 2007 Plan for the three years ended December 31, 2017:


		Weighted Average		Aggregate Grant
	Number Outstanding	Grant Date Fair Value		Date Fair Value
Balance as of December 31, 2014	525,356	$	13.71	$	8,786,611
Shares granted	146,440		18.53		2,713,159
Shares forfeited	—		—		—
Shares vested	(275,201)		15.87		(4,368,570)
Balance as of December 31, 2015	396,595	$	17.98	$	7,131,200
Shares granted	136,645		21.55		2,944,941
Shares forfeited	(20,377)		17.79		(362,536)
Shares vested	(213,528)		17.12		(3,655,269)
Balance as of December 31, 2016	299,335	$	20.24	$	6,058,336
Shares granted	215,603		24.89		5,365,731
Shares forfeited	(10,999)		24.38		(268,200)
Shares vested	(175,817)		19.61		(3,448,628)
Balance as of December 31, 2017	328,122	$	23.49	$	7,707,239

At December 31, 2017 the stock compensation expense related to the restricted stock awards that will be recognized over the average remaining vesting period of 1.7 years totalled $5.1 million. At December 31, 2017, the intrinsic value of unvested restricted stock awards is $8.2 million. The 2007 Plan was extend in May 2015 for 5 years until May 2020.

Under the Employee Stock Purchase Plan (“ESPP”), as amended and restated effective May 20, 2010, 250,000 shares of common stock have been reserved for issuance. Eligible employees may designate not more than 10% of their cash compensation to be deducted each pay period for the purchase of common stock under the Purchase Plan. Participants may purchase not more than 1,000 shares or $25,000 of common stock in any one calendar year. Each January 31 and July 31 shares of common stock are purchased with the employees’ payroll deductions from the immediately preceding six months at a price per share of 85% of the lesser of the market price of the common stock on the purchase date or the market price of the common stock on the date of entry into an offering period. In 2017, 2016, and 2015, 11,485, 11,014, and 10,374 shares of common stock, respectively, were issued under the ESPP. The Company issues new shares through its transfer agent upon employee stock purchase. The weighted average per share fair value of the employee’s purchase rights under the Purchase Plan for the rights granted was $7.39, $6.35 and $6.17 for 2017, 2016 and 2015, respectively.

The Company granted stock options under its 1996 Stock Option/Stock Issuance Plan (the “1996 Plan”), as amended and restated as of March 1, 2003, until the plan terminated in June 2006. In the year ended December 31, 2015, 49,000 options were exercised with a total intrinsic value at exercise date of approximately $0.3 million. There are no options remaining under the 1996 Plan.