8. Equity Compensation

 

Stock Options

In 2003, the Board of Directors adopted the 2003 Equity Incentive Plan (the “2003 Plan”), which provided for the granting of nonqualified and incentive stock options, stock appreciation rights, stock awards and restricted stock. Under the 2003 Plan, the Company was able to grant nonqualified and incentive stock options to directors, employees and non‑employees providing services to the Company. On June 11, 2013, the Company’s Board of Directors adopted the 2013 Stock Option and Incentive Plan (the “2013 Plan”), which was subsequently approved by the Company’s stockholders. The 2013 Plan became effective as of the closing of the Company’s initial public offering. To the extent that any awards outstanding under the 2003 Plan are forfeited or lapse unexercised subsequent to August 1, 2013, the shares of common stock subject to such awards will become available for issuance under the 2013 Plan. The 2013 Plan provides for annual increases in the number of reserved shares of up to 5% of the outstanding number of shares of the Company’s Common Stock as of the preceding December 31. The Company and its Board of Directors decided to forego increasing the number of reserved shares on January 1, 2016, and will revisit this option for an annual increase next year.

 

A summary of stock option activity for the years ended December 31, 2013, 2014 and 2015 is presented below:

 

The following table summarizes information about stock options outstanding and exercisable at December 31, 2015:

 

The total fair value of stock option awards vested during the year ended December 31, 2015 was $8.0 million. The following table summarizes the aggregate intrinsic‑value of options exercised, outstanding and exercisable (in thousands):

 

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

 

Restricted stock units

 

A summary of restricted stock unit activity for the year ended December 31, 2015 is presented below:

 

The aggregate intrinsic value of unvested restricted stock at December 31, 2015 was $3.1 million.  The aggregate intrinsic value represents the total pretax intrinsic value, based on the Company’s stock price of $7.27 as of December 31, 2015, which would have been received by the restricted stock award holders had all restricted stock awards been vested as of that date.  

 

Stock-based compensation expense

 

Total stock‑based compensation expense has been classified as follows in the accompanying Consolidated Statements of Operations (in thousands):

 

At December 31, 2015, there was $11.7 million of total unrecognized compensation cost related to non‑vested stock option awards that will be recognized over a weighted‑average period of 2.4 years.  At December 31, 2015, there was $3.2 million of total unrecognized compensation cost related to non-vested restricted stock units that will be recognized over a weighted-average period of 3.6 years.