Total share-based compensation related to stock options, common stock awards, and warrants was $286,460 and $147,228 during the three months ended March 31, 2016 and 2015, respectively.

Share-based compensation expense is classified in the condensed consolidated statements of comprehensive loss as follows:

Employee Stock Options

During the three months ended March 31, 2016, the Company granted 400,000 employee stock options. The key valuation assumptions used consisted of the Company’s stock price, a risk free rate of 0.54% and an expected volatility of 123%. There were no employee stock options granted during the same period in 2015. During the three months ended March 31, 2016, the Company extended the exercise expiration date of certain former employee stock option awards resulting in a change in incremental value of approximately $24,000 which was charged to administrative expense. The Company recognized a total of $478,859 and $63,634 of compensation expense related to employee stock options during the three months ended March 31, 2016 and 2015, respectively.

Non-Employee Stock Options

No non-employee stock options were granted no non-employee stock options were exercised during the three months ended March 31, 2016 or 2015. The Company recognized ($971) and $4,438 of compensation expense related to non-employee stock options during the three months ended March 31, 2016 and 2015, respectively.

Common Stock Awards

During the three months ended March 31, 2016 and 2015, the Company granted 285,350 and 104,957 common stock awards, respectively, based on the value of the services provided and the average stock price during each respective quarter. As all services were rendered in each respective quarter, $57,790 and $25,500 of compensation expense related to common stock awards was recognized during each of the three month periods ended March 31, 2016 and 2015, respectively. All common stock awards were authorized but not issued as of March 31, 2016.

Warrants

In connection with certain of the Company’s collaboration agreements and consulting arrangements, the Company has issued warrants to purchase shares of common stock. As of March 31, 2016, and December 31, 2015, warrants to purchase 13,025,000 shares of common stock were outstanding. These warrants were fair valued at each issuance date using the Black-Scholes option pricing model. The warrants are subject to re-measurement at each reporting period until the measurement date is reached. Expense is recognized on a straight-line basis over the expected service period or at the date of issuance, if there is not a service period. Expense for the three months ended March 31, 2016, was offset by reduction in estimated fair value resulting in a net reduction to expense of $249,218.

The Company issued no warrants in connection with collaboration agreements and consulting services during the three months ended March 31, 2016 and 2015.