The Company has authorized 150,000,000 shares of common stock, $0.0001 par value per share, of which 98,852,696 shares, and 64,672,893 shares were issued and outstanding as of December 31, 2020, and 2019, respectively.

On January 30, 2019, the Company consummated an underwritten public offering of shares of its common stock pursuant to which the Company sold an aggregate of 6,198,500 shares of its common stock, including 808,500 shares sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a purchase price of $6.50 per share with gross proceeds to the Company totaling approximately $40,300,000, less issuance costs incurred of approximately $2,600,000 million.

On February 11, 2020, the Company consummated an underwritten public offering of shares of its common stock pursuant to which the Company sold an aggregate of 7,666,667 shares of its common stock, including 1,000,000 shares sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a purchase price of $6.00 per share with gross proceeds to the Company totaling $46,000,000, less estimated issuance costs incurred of approximately $3,147,000.

On April 7, 2020, the Company entered into the April 2020 Sale Agreement with Jefferies pursuant to which Jefferies served as the Company’s sales agent to sell up to $75,000,000 of shares of the Company’s common stock through an “at the market offering.” Sales of common stock under the April 2020 Sale Agreement were made pursuant to an effective registration statement for an aggregate offering of up to $75,000,000. During the year ended December 31, 2020, the Company sold 10,539,374 shares of its common stock under the April 2020 Sale Agreement for which the Company received gross proceeds of approximately $75,000,000, less issuance costs incurred of approximately $2,250,000 through December 31, 2020. This Sale Agreement has expired and is no longer effective.

On August 7, 2020, the Company entered into the August 2020 Sale Agreement with Jefferies pursuant to which Jefferies is serving as the Company’s sales agent to sell shares of the Company’s common stock through an “at the market offering.” As of August 7, 2020, the company was authorized to sell up to $150,000,000 of shares of the Company’s common stock pursuant to the August 2020 Sale Agreement. During the year ended December 31, 2020. During the year ended December 31, 2020, the Company sold 15,546,151 shares of its common stock under the August 2020 Sale Agreement for which the Company received gross proceeds of approximately $21,404,000, less issuance costs incurred of approximately $642,000 through December 31, 2020.

During the year ended December 31, 2020 and 2019, the Company issued 427,611 and 107,029 shares of common stock upon the exercise of stock options to purchase common stock and the Company received proceeds of approximately $756,000 and $387,000 from these exercises, respectively.

No warrants were exercised during the year ended December 31, 2020. During the year ended December 31, 2019, warrants to purchase 1,283,500 shares of stock were exercised on a cashless basis resulting in the issuance of 1,119,868 shares of common stock.