The Company has two equity incentive compensation plans: a 2006 Stock Incentive Plan and a 2016 Stock Incentive Plan.

2006 Stock Incentive Plan – The 2006 Stock Incentive Plan authorized the issuance of incentive stock options (“ISOs”) and non-qualified stock options (“NQOs”), restricted stock, restricted stock units, stock appreciation rights, direct stock issuances and other stock-based awards to the Company’s officers, directors or key employees or to consultants that do business with the Company for up to an aggregate of 1,715,000 shares of common stock. In June 2016, this plan was terminated, except to the extent of issued and outstanding unvested stock awards and options.

2016 Stock Incentive Plan – On June 16, 2016, the Company’s shareholders approved the 2016 Stock Incentive Plan, which authorizes the issuance of ISOs, NQOs, restricted stock, restricted stock units, stock appreciation rights, direct stock issuances and other stock-based awards to the Company’s officers, directors or key employees or to consultants that do business with the Company for up to an aggregate of 1,150,000 shares of common stock.

Stock Options – Summaries of the status of Company’s stock option plans as of December 31, 2017 and 2016 and of changes in options outstanding under the Company’s plans during those years are as follows (number of shares in thousands):

Stock options outstanding as of December 31, 2017 were as follows (number of shares in thousands): 

The options outstanding at December 31, 2017 and 2016 had intrinsic values of $84,000 and $1,319,000, respectively. The intrinsic value of options exercised in 2017 was approximately $30,000.

Restricted Stock – The Company granted to certain employees and directors shares of restricted stock under its 2006 and 2016 Stock Incentive Plans. A summary of unvested restricted stock activity is as follows (shares in thousands):

The fair value of the common stock at vesting aggregated $3,210,000, $1,142,000 and $2,603,000 for the years ended December 31, 2017, 2016 and 2015, respectively. Stock-based compensation expense related to employee and non-employee restricted stock and option grants recognized in selling, general and administrative expenses, were as follows (in thousands):

Employee grants typically have a three year vesting schedule, while the non-employee grants have a one year vesting schedule. At December 31, 2017, the total compensation expense related to unvested awards which had not been recognized was $4,122,000 and the associated weighted-average period over which the compensation expense attributable to those unvested awards will be recognized was approximately 1.54 years.