The Company has authorized 150,000,000 shares of common stock, $0.0001 par value per share, of which 57,247,496 shares, and 55,603,427 shares were issued and outstanding as of December 31, 2018, and 2017, 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 $36,291.

On October 26, 2017, the Company consummated an underwritten public offering of shares of its common stock pursuant to which the Company sold an aggregate of 4,650,000 shares of its common stock at a purchase price of $7.00 per share with gross proceeds to the Company totaling $32,550,000, less estimated issuance costs incurred of approximately $2,184,000. The Company also granted the underwriters a 30-day option to purchase up to an additional 697,500 shares of common stock on the same terms as the underwriters were purchasing the base number of shares, which they exercised in November 2017 with net proceeds to the Company totaling $4,589,550.

On January 5, 2018, the Company entered into a sales agreement with Cantor Fitzgerald under which the Company had the ability to direct Cantor Fitzgerald as its sales agent to sell common stock up to an aggregate offering of up to $50 million under an “At the Market Offering” (“January 2018 Sales Agreement”). Sales of common stock under the January 2018 Sales Agreement were made pursuant to an effective registration statement for an aggregate offering of up to $50 million. During the first quarter of 2018, the Company sold 1,500,000 shares of its common stock to an institutional investor under the January 2018 Sales Agreement for which the Company received net proceeds of approximately $11.2 million. The Company did not sell any shares under the January 2018 Sales Agreement in remainder of 2018 and through February 8, 2019, the effective date of the Company’s termination of the January 2018 Sales Agreement (see Note 15). During the year ended December 31, 2017, the Company sold 1,413,633 shares of its common stock under a sales agreement that the Company entered into in November 2016 with Cantor Fitzgerald (“Sales Agreement”) for net proceeds of $13,268,208. The Sales Agreement was terminated in October 2017.

During the year ended December 31, 2018, the Company issued 144,069 shares of common stock upon the exercise of stock options and warrants to purchase common stock and the Company received net proceeds of $352,645 from these exercises. During the year ended December 31, 2017, the Company issued 272,734 shares of common stock upon the exercise of stock options and warrants to purchase common stock and the Company received net proceeds of $189,490 from these exercises.

On January 30, 2019, the Company consummated an underwritten public offering of shares of its common stock. See Note 15.