Stockholders' Deficit

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Stockholders' Deficit

Stockholders' Deficit

ATM Offering

On April 15, 2022, the Company filed a new registration statement on Form S-3 to replace its prior automatically effective registration statement on Form S-3ASR filed on August 3, 2021, which registered the offering, issuance and sale of up to $239 million of common stock from time to time in “at-the-market” offerings (the “New ATM Program”). On February 21, 2023, the Company terminated the Open Market Sales Agreement with Jefferies LLC and entered into a Controlled Equity Offering Sales Agreement with Cantor Fitzgerald & Co., as sales agent, to provide for the issuance and sale by the Company of up to $70 million of shares of the Company's common stock from time to time in “at-the-market” offerings (the "2023 ATM Program"), pursuant to its existing Form S-3 and the prospectus supplement to be filed on February 21, 2023. The Company may continue to use the 2023 ATM Program to address potential short-term or long-term funding requirements that may arise. Such program will continue to be subject to the volatility of the price of the Company's common stock and general market conditions. During the year ended December 31, 2022, the Company issued 13,043,797 shares of common stock resulting in net proceeds of approximately $90.8 million after deducting $3.1 million of underwriting discounts and commissions and other expenses, pursuant to the New ATM Program. During the year ended December 31, 2023, the Company issued 3,312,908 shares of common stock resulting in net proceeds of approximately $4.4 million after deducting $0.4 million of underwriting discounts and commissions and other expenses, pursuant to the 2023 ATM Program.

Warrants

In connection with an underwriting agreement with H.C. Wainwright & Co., LLC ("Wainwright") on December 2, 2021, the Company issued warrants to purchase 36,964,286 shares of common stock at an exercise price of $9.00 and an expiration date of December 7, 2023. The warrants were recorded at fair value of $61.9 million to additional-paid-in-capital in accordance with ASC 815-10 based upon the allocation of the proceeds between the common shares issued with the December 2021 Offering and the warrants. On December 7, 2023, 27,940,074 of these warrants expired. The remaining 9,024,212 warrants were amended as described below.

Registered Direct Offering and Warrant Amendment

On March 19, 2023, the Company entered into a Purchase Agreement with the Purchasers pursuant to which the Company agreed to issue and sell, in a Registered Direct Offering, 12,205,000 shares of its Common Stock, par value $0.001 per share, Pre-Funded Warrants to purchase up to an aggregate of 20,965,747 shares of Common Stock in lieu of shares of Common Stock, and Warrants to purchase up to 33,170,747 shares of Common Stock. The combined purchase price of each share of Common Stock and accompanying Warrant is $1.675 per share. The Warrants expire on September 22, 2026 and have an

exercise price of $1.55. The purchase price of each Pre-Funded Warrant is $1.674 (equal to the combined purchase price per share of Common Stock and accompanying Warrant, minus $0.001). The Purchase Agreement contains customary representations, warranties, covenants and indemnification rights and obligations of the Company and the Purchasers. The Registered Direct Offering closed on March 22, 2023. The warrants and pre-funded warrants were recorded at fair value of $22.8 million to additional-paid-in-capital in accordance with ASC 815-10 based upon the allocation of the proceeds between the common shares issued with the Registered Direct Offering and the warrants and pre-funded warrants. The Company estimated the fair value of the warrants using a Black-Scholes option-pricing model, which is based, in part, upon subjective assumptions including but not limited to stock price volatility, the expected life of the warrant, the risk-free interest rate and the fair value of the common stock underlying the warrant. The Company estimates the volatility based on its historical volatility that is in line with the expected remaining life of the warrants. The risk-free interest rate is based on the U.S. Treasury daily rate for a maturity similar to the expected remaining life of the warrants. The expected remaining life of the warrants is assumed to be equivalent to its remaining contractual term. The Company estimated the fair value of the pre-funded warrants based on the market price of the Company's common stock at issuance.

In connection with the Registered Direct Offering, the Company amended, pursuant to Warrant Amendment Agreements certain existing warrants to purchase up to an aggregate of 9,024,212 shares of the Company's common stock that were previously issued in December 2021 at an exercise price of $9.00 per share and had an expiration date of December 7, 2023, effective upon the closing of the Registered Direct Offering, such that the amended warrants have a reduced exercise price of $1.55 per share and expire three and one half years following the closing of the Registered Direct Offering, or September 22, 2026, for additional consideration of $0.125 per amended warrant. Based on the change in the fair value of the amended warrants, the Company recorded issuance costs to additional paid-in capital of $2.9 million.

The Company received gross proceeds of approximately $55.5 million from the Registered Direct Offering, before deducting placement agent fees and related offering expenses. The net proceeds to the Company from the Registered Direct Offering, after deducting the placement agent fees and expenses and the Company’s estimated offering expenses of $4.2 million, were approximately $51.3 million. In addition, the Company received approximately $1.2 million as the gross consideration in connection with the Warrant Amendment Agreements. The net proceeds of the Warrant Amendment Agreements after deducting placement fees of $0.1 million were approximately $1.1 million.

During the year ended December 31, 2023, 20,965,747 shares of pre-funded warrants were exercised and 5,850,747 shares of warrants were exercised. As of December 31, 2023, no pre-funded warrants were outstanding. The following table summarizes the warrants outstanding for the Company as of December 31, 2023 and 2022:

	December 31, 2023	December 31, 2022	Weighted average exercise price
Warrants outstanding from 2021 agreement, expiring December 7, 2023	—	36,964,286	$	9.00
Warrants outstanding from Warrant Amendment Agreements, expiring September 22, 2026	9,024,212	—	$	1.55
Warrants outstanding from Purchase Agreement, expiring September 22, 2026	27,320,000	—	$	1.55
Total warrants outstanding	36,344,212	36,964,286