As of September 30, 2019, the Company was authorized to issue 100 million shares of common stock par value $0.001 per share, of which 41,092,340 and 35,335,378 shares were issued outstanding as of September 30, 2019 and December 31, 2018, respectively.

On June 14, 2019, an amendment to the 2015 Stock Incentive Plan (the “2015 Plan”) was approved by the stockholders at the annual meeting to increase the number of shares of common stock available for issuance under the 2015 Plan by 1,000,000 shares to an aggregate maximum of 4,250,000 shares.

Issuances Upon Warrant and Option Exercises

From January 30, 2019 to February 26, 2019, warrants to purchase 754,475 shares of our common stock were exercised at a price of $2.20 per share, for gross proceeds to the Company of approximately $1.66 million.

On March 8, 2019, Cotterford Company Limited partially exercised its warrant and purchased 1,724,138 shares of our common stock at a price of $2.90 per share, for gross proceeds to the Company of $5.0 million.

On May 3, 2019, Cotterford Company Limited partially exercised its warrant and purchased 1,666,667 shares of our common stock at a price of $3.00 per share, for gross proceeds to the Company of $5.0 million.

On July 24, 2019, Cotterford Company Limited exercised the remainder of its warrant and purchased 1,609,195 shares of our common stock at a price of $3.00 per share, for gross proceeds to the Company of $4.8 million.

From August 20, 2019 to September 20, 2019, 6,166 stock options were exercised to purchase shares of common stock at $2.35 per share in a cashless exercise that resulted in the issuance of 2,487 shares of our common stock.

Equity Distribution Agreement

On September 7, 2018, the Company entered into an equity distribution agreement with Oppenheimer & Co. Inc. (“Oppenheimer”), which agreement allows it to offer and sell shares of common stock having an aggregate offering price of up to $10.0 million from time-to-time pursuant to a shelf registration statement on Form S-3 (declared effective by the SEC on September 28, 2018, File No. 333-227248) through Oppenheimer acting as the Company’s agent and/or principal. As of September 30, 2019, the Company had not sold any shares under the equity distribution agreement.