Stock-Based Compensation | Stock Options Opexa accounts for stock-based compensation, including options and nonvested shares, according to the provisions of FASB ASC 718, "Share Based Payment.” During the three months ended March 31, 2017, Opexa recognized stock-based compensation expense of $48,277. Unamortized stock-based compensation expense as of March 31, 2017 amounted to $235,340. Stock Option Activity A summary of stock option activity for the three months ended March 31, 2017 Number of Shares Weighted Avg. Exercise Price Weighted Average Remaining Contract Term (# years) Intrinsic Value Outstanding at December 31, 2016 481,947 $ 12.14 7.60 — Exercised — — Forfeited and canceled (187,351 ) 11.93 Outstanding at March 31, 2017 294,596 $ 12.28 7.19 $ — Exercisable at March 31, 2017 244,868 $ 13.69 6.92 $ — Employee Options and Non-Employee Options Option awards are granted with an exercise price equal to the market price of Opexa’s stock at the date of issuance, generally have a ten-year life, and have various vesting dates that range from no vesting or partial vesting upon date of grant to full vesting on a specified date. Opexa estimates the fair value of stock options using the Black-Scholes option-pricing model and records the compensation expense ratably over the service period. Opexa recognized stock based compensation expense of $48,277 and $153,853 during the three months ended March 31, 2017 and 2016, respectively, for grants made to employees. In addition, during the three months ended March 31, 2017 there were 187,351 shares underlying options that were forfeited and cancelled. There were no stock options or restricted stock awards granted during the three months ended March 31, 2017. Warrant Activity A summary of warrant activity for the three months ended March 31, 2017 Number of Shares Weighted Avg. Exercise Price Weighted Average Remaining Contract Term (# years) Intrinsic Value Outstanding at December 31, 2016 3,596,625 $ 12.39 1.21 — Forfeited and canceled (127,894 ) 12.72 Outstanding at March 31, 2017 3,468,731 12.38 1.00 $ — Exercisable at March 31, 2017 3,468,731 12.38 1.00 $ — |