Total share-based compensation related to stock options, common stock awards, warrants and Joint Share Ownership Plan awards was $89,970 and $43,325 for the three months ended June 30, 2015 and 2014, respectively, and $237,198 and $432,250 for the six months ended June 30, 2015 and 2014, respectively.

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

Employee Stock Options

During the six months ended June 30, 2015 and 2014, no employees were granted stock options to purchase shares of common stock. There were no employee stock option exercises during the six months ended June 30, 2015. During the six months ended June 30, 2014, a named executive of the Company exercised 1,984,080 stock options. Cash received from stock option exercise was $101,933. The Company recognized compensation expense related to employee stock options of $20,668 and $11,826 during the three months ended June 30, 2015 and 2014, respectively, and $84,303 and $24,899 during the six months ended June 30, 2015 and 2014, respectively.

Non-Employee Stock Options

No non-employee stock options were granted during the six months ended June 30, 2015 or 2014 and no non-employee stock options were exercised during the six months ended June 30, 2015 or 2014. The Company recognized compensation expense related to non-employee stock options of $4,755 and $5,999 during the three months ended June 30, 2015 and 2014, respectively, and $9,193 and $11,446 during the six months ended June 30, 2015 and 2014, respectively.

Common stock awards

The Company granted 129,331 and 30,514 common stock awards during the three months ended June 30, 2015 and 2014, respectively, and 234,288 and 67,419 common stock awards during the six months ended June 30, 2015 and 2014, respectively, based on the value of the services provided and the average stock price during each respective period. As all services were rendered in each respective period, the Company recognized compensation expense related to common stock awards of $25,500 during each of the three month periods ended June 30, 2015 and 2014 and $51,000 during each of the six month periods ended June 30, 2015 and 2014, respectively. All common stock awards were authorized but not issued as of June 30, 2015.

Warrants

In connection with the Company’s collaboration agreements, the Company issued warrants to purchase 10,425,000 shares of common stock to its collaborative partners on December 31, 2014. A warrant to purchase 1,600,000 shares of common stock was also issued to a non-employee director for consulting services provided to the Company on December 31, 2014. These warrants were fair valued at 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. No warrants to purchase common stock were issued during the six months ended June 30, 2015 or 2014, respectively.