The Company is authorized to issue 510,000,000 shares of capital stock of which 500,000,000 shares are designated as common stock and 10,000,000 shares are designated as preferred stock, all with a par value of $0.0001 per share. Each holder of common stock is entitled to one vote for each share of common stock held. The Company’s common stock is not entitled to preemptive rights, and is not subject to conversion, redemption or sinking fund provisions. Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of common stock are entitled to receive dividends out of funds legally available if the board of directors, in its discretion, determines to issue dividends and then only at the times and in the amounts that the board of directors may determine. As of December 31, 2020 and 2019, no common stock dividends had been declared by the board of directors and there were no shares of preferred stock outstanding.

In April 2018, the Company issued and sold 5,046,510 shares of common stock in an underwritten public offering pursuant to a shelf registration statement on Form S-3 at a public offering price of $8.00 per share, including 546,510 shares of common stock issued upon the partial exercise by the underwriters of their option to purchase additional shares. The net proceeds to the Company from this public offering were $37.7 million, after deducting underwriting discounts and commissions of $2.4 million and offering costs of $0.3 million.

In February 2019, the Company issued and sold 4,625,000 shares of common stock at a public offering price of $8.00 per share and pre-funded warrants to purchase up to 4,000,000 shares of common stock at a public offering price of $7.9999 per warrant in an underwritten public offering pursuant to a shelf registration statement on Form S-3. This includes the full exercise by the underwriters of their option to purchase up to 1,125,000 additional shares of common stock. The net proceeds to the Company from this public offering were $64.5 million, after deducting underwriting discounts and commissions of $4.1 million and offering costs of $0.4 million.

In April 2020, the Company issued and sold 15,442,303 shares of common stock at a public offering price of $4.75 per share and pre-funded warrants to purchase up to 13,610,328 shares of common stock at a public offering price of $4.7499 per warrant in an underwritten public offering pursuant to a shelf registration statement on Form S-3. This includes the full exercise by the underwriters of their option to purchase up to 3,789,473 additional shares of common stock. The net proceeds to the Company from this public offering were $129.0 million, after deducting underwriting discounts and commissions of $8.2 million and offering costs of $0.8 million.

The public offering price for the pre-funded warrants sold in February 2019 and April 2020 was equal to the public offering price of the common stock, less the $0.0001 per share exercise price of each warrant. The warrants were recorded as a component of stockholders’ equity within additional paid-in capital and have no expiration date. Per the terms of the warrant agreements, the outstanding warrants to purchase shares of common stock may not be exercised if the holder’s ownership of the Company’s common stock would exceed 4.99% (“Maximum Ownership Percentage”). By written notice to the Company, the holders of the pre-funded warrants purchased in February 2019 may increase or decrease the Maximum Ownership Percentage, and the holders of the pre-funded warrants purchased in April 2020 may increase or decrease the Maximum Ownership Percentage to any other percentage not in excess of 19.99%. The revised Maximum Ownership Percentage would be effective 61 days after the notice is received by the Company.

As of December 31, 2020, the following pre-funded warrants to purchase common stock were issued and outstanding:

Issue Date	Expiration Date	Exercise Price		Number of Warrants Outstanding
February 8, 2019	None	$	0.0001		4,000,000
April 30, 2020	None	$	0.0001		13,610,328
Total pre-funded warrants					17,610,328

In May 2017, the Company entered into a sales agreement with JonesTrading Institutional Services LLC, as sales agent and underwriter, to issue and sell shares of its common stock for an aggregate offering price of $20.0 million under an at-the-market (“2017 ATM’) offering program. In October 2018, the Company issued and sold 1,845,820 shares of common stock in a single transaction under the 2017 ATM, for gross proceeds $17.0 million, resulting in net proceeds of $16.4 million, after deducting underwriting discounts, commissions, and offering costs. The 2017 ATM agreement was subsequently terminated in December 2018.

In April 2020, the Company entered into a new sales agreement with JonesTrading Institutional Services LLC, as sales agent, to issue and sell shares of its common stock for an aggregate offering price of $60.0 million under an at-the-market (“2020 ATM”) offering program. In the fourth quarter of 2020, the Company issued and sold 3,245,077 shares of common stock under the 2020 ATM for gross proceeds of $25.3 million, resulting in net proceeds of $24.6 million, after deducting underwriting discounts, commissions, and offering costs. As of the date of the filing of this report, $34.7 million of our common stock remained available for sale pursuant to the 2020 ATM.