At March 31, 2015 there were warrants outstanding to purchase 13,647,848 shares with a weighted average exercise price of $0.99 and a weighted average remaining life of 4.3 years. During the three months ended March 31, 2015, warrants to purchase 62,129 shares of common stock were exercised.

In October 2009, the Company issued warrant agreements with a five year term to holders of convertible bridge notes. Under the terms of each warrant agreement, the exercise price and number of shares were determined upon the completion on a qualified financing, which occurred when the Series A convertible preferred stock financing closed in 2013 at which time the warrants could be exercised to purchase 27,839 shares of common stock at an exercise price of $0.60 per share. The Company valued these warrants at $1,005 and charged the cost to interest expense with an offset to additional paid-in capital.

In June 2013, the Company issued warrants to purchase 301,778 shares of common stock at an exercise price of $0.66 per share in exchange for services provided. These warrants were valued at $21,910 in June 2013 and expensed to general and administrative expenses with an offset to derivative liability. On June 30, 2014, the Company issued an additional 48,222 warrants to the warrant holder in exchange for a settlement of a claim and modification of the warrant terms and to eliminate the anti-dilution protection (See Note 11).

In connection with a private placement in 2014, the Company issued warrants to investors and former holders of Series A Convertible Preferred Stock to purchase an aggregate of 11,177,612 shares of common stock with an exercise price of $1.00 per share and a five year term. These warrants have a provision that permits the Company to call and redeem the warrants after a thirty day notice period if the stock trades at $2.50 or greater on a volume weighted average basis for at least twenty consecutive trading days. In addition, the Company issued warrants to the Placement Agent to purchase 2,047,000 shares of common stock with an exercise price of $1.00 per share and a five year term. These warrants contain a cashless exercise feature and the fair value of the warrants was recorded as a stock issuance cost and net against the gross proceeds received.