On June 19, 2014, at the Annual Meeting of Stockholders (the “Annual Meeting”), the stockholders approved the 2014 Plan, which was approved by the Board on February 21, 2014.  On July 16, 2007 (the “Effective Date”), the Company’s Board and stockholders adopted the Plan.  On July 17, 2012, the Company’s Board and stockholders amended the Plan to increase the aggregate number of options available for grant to 903,224. Additionally, the Board also, approved subject to stockholder approval at the Annual Meeting under the Prospective Plan, 800,000 shares of common stock plus an annual increase to be added as of the first day of the Company’s fiscal year, beginning in 2015 and occurring each year thereafter through 2020, equal to the lower of 200,000, or 1% of the outstanding shares of common stock as of the end of the Company’s immediately preceding fiscal year and  any lesser number of shares determined by the Board, provided that the aggregate number of shares available for issuance pursuant to such increases shall not exceed a total of 800,000 shares reserved for issuance under the terms of  the  Prospective Plan.  The aggregate options approved in the Plan and 2014 Plan as of December 31, 2015 is 1,788,628 with 1,464,203 outstanding and expected to vest and 324,425 available for future issuance as of December 31, 2015. During the year ended December 31, 2015, 7,514 options were exercised; such options were included in the Plan. 
 

The Plan provides for the Board or a Committee of the Board (the “Committee”) to grant awards to optionees and to determine the exercise price, vesting term, expiration date and all other terms and conditions of the awards, including acceleration of the vesting of an award at any time.  All options granted under the Plan are intended to be incentive stock options (“ISOs”), unless specified by the Committee to be non-qualified options (“NQOs”) as defined by the Internal Revenue Code.  ISOs and NQOs may be granted to employees, consultants or Board members at an option price not less than the fair market value of the common stock subject to the Stock Option Agreement.  The following table summarizes information about stock options outstanding as of December 31, 2015 and 2014:

The weighted average remaining contractual term of stock options outstanding and expected to vest at December 31, 2015 is 7.2 years.  The weighted average remaining contractual term of stock options exercisable at December 31, 2015 is 6.1 years. 

Stock-based compensation expense for the years ended December 31, 2015 and 2014 was:

As of December 31, 2015, the total unrecognized compensation expense related to unvested options totaled $2,657,226.  The weighted-average vesting period over which the total compensation expense will be recorded related to unvested options at December 31, 2015 was approximately 2.7 years.

The aggregate intrinsic value is calculated as the difference between (i) the closing price of the common stock at December 31, 2015 and (ii) the exercise price of the underlying awards, multiplied by the number of options that had an exercise price less than the closing price on the last trading day. The Company’s outstanding and exercisable options had an intrinsic value of $952,773 and $880,457 as of December 31, 2015, respectively.