The Company has authorized 150,000,000 shares of common stock, $0.0001 par value per share, of which 50,220,510 shares and 44,681,745 shares were issued and outstanding as of June 30, 2017 and December 31, 2016, respectively.

On February 28, 2017, the Company entered into a securities purchase agreement providing for the issuance and sale by the Company of 3,887,815 shares of its common stock in a registered direct offering to institutional and accredited investors at a purchase price of $7.00 per share with gross proceeds to the Company totaling $27,214,705 less issuance costs of approximately $36,291.

In November 2016, the Company entered into a sales agreement with Cantor Fitzgerald (“Cantor”) under which the Company may direct Cantor as its placement agent to sell common stock under an “At the Market Offering” (“Sales Agreement”). Sales of common stock under the Sales Agreement are made pursuant to an effective registration statement for an aggregate offering of up to $35 million, under which the Company has sold an aggregate of approximately $15.4 million of common stock through June 30, 2017. Under the Sales Agreement, the Company is obligated to pay Cantor a 3% commission on gross proceeds. During the three months ended March 31, 2017, the Company sold 1,413,633 shares of its common stock under the Sales Agreement at an average selling price of approximately $9.71 per share for gross proceeds of $13,724,591 and net proceeds of $13,268,208. During the three months ended June 30, 2017, the Company did not sell any shares of its common stock under the Sales Agreement.

During the three months ended June 30, 2017, the Company issued 76,768 shares of common stock upon the exercise of stock options to purchase common stock and the Company received proceeds of $20,555 from these exercises. During the six months ended June 30, 2017, the Company issued 237,317 shares of common stock upon the exercise of stock options to purchase common stock and the Company received proceeds of $100,803 from these exercises.