9. Warrants

The activity related to warrants during the years ended December 31, 2025 and 2024, is summarized as follows:

At December 31, 2025, the range of exercise prices for shares under warrants and the weighted-average remaining contractual life is as follows:

2025 Pre-Funded Warrants

In September 2025, the Company issued and sold pre-funded warrants to purchase up to an aggregate of 5,845,455 shares of common stock to the September 2025 Purchasers at a purchase price of $0.549 per share and an exercise price of $0.001 per share (see Note 8, “Stockholders’ Equity” for additional information). The pre-funded warrants were exercisable immediately, subject to beneficial ownership restrictions, and have an unlimited term. In November 2025, 1,000,000 of these pre-funded warrants were exercised.

In April 2025, the Company issued and sold pre-funded warrants to purchase up to an aggregate of 4,999,316 shares of common stock to the April 2025 Purchasers at a purchase price of $0.585 per share and an exercise price of $0.001 per share (see Note 8, “Stockholders’ Equity” for additional information). The pre-funded warrants were exercisable immediately, subject to beneficial ownership restrictions, and have an unlimited term.

All the pre-funded warrants issued by the Company in April and September 2025 were classified as a component of permanent equity in the Company's consolidated balance sheet as they are freestanding financial instruments that are immediately exercisable, do not embody an obligation for the Company to repurchase its own shares and permit the holders to receive a fixed number of shares of common stock upon exercise. All of the shares underlying the pre-funded warrants are included in the weighted-average number of shares of common stock used to calculate net loss per share attributable to common stockholders because the shares may be issued for little or no consideration and are fully vested and are exercisable after their original issuance date. The pre-funded warrants may participate with common shareholders in dividends or other distributions.

In October 2025, the Company issued and sold additional pre-funded warrants to purchase up to an aggregate of 1,706,484 shares of common stock at a purchase price of $0.585 per share and an exercise price of $0.001 per share, to certain April 2025 Purchasers that elected to waive the April 2025 Private Placement milestone requirements for the second and third closings. The pre-funded warrants were exercisable immediately, subject to beneficial ownership restrictions, and have an unlimited term. In October 2025, the 1,706,484 pre-funded warrants were exercised in full.

As of December 31, 2025, there were 4,999,316 pre-funded warrants outstanding in connection with the April 2025 Private Placement and 4,845,455 pre-funded warrants outstanding in connection with the September 2025 Private Placement.

January 2024 Pre-Funded Warrants and Amendment of Prior Warrants

On January 17, 2024, the Company issued the January 2024 Pre-Funded Warrants to purchase up to an aggregate of 7,792,208 shares of Common Stock in the first tranche of the two-tranche January 2024 Private Placement (see Note 8, “Stockholders’ Equity”). The January 2024 Pre-Funded Warrants were exercisable immediately following the closing date of the first tranche of the January 2024 Private Placement, or January 22, 2024, and have an unlimited term and an exercise price of $0.001 per share.

The January 2024 Pre-Funded Warrants were classified as a component of permanent equity in the Company's consolidated balance sheet as they are freestanding financial instruments that are immediately exercisable, do not embody an obligation for the Company to repurchase its own shares and permit the holders to receive a fixed number of shares of Common Stock upon exercise. All of the shares underlying the January 2024 Pre-Funded Warrants have been included in the weighted-average number of shares of Common Stock used to calculate net loss per share attributable to common stockholders because the shares may be issued for little or no consideration and are fully vested and are exercisable after their original issuance date. The January 2024 Pre-Funded Warrants may participate with common shareholders in dividends or other distributions.

In July 2023, in connection with the July 2023 Private Placement Warrants (see below), the Company issued to certain of the July 2023 Purchasers (i) Series A common stock warrants to purchase up to 3,676,473 shares of Common Stock and (ii) Series B common stock warrants to purchase up to 3,676,473 shares of Common Stock, or collectively, the Prior Warrants. In connection with the January 2024 Private Placement, the Company and the January 2024 Purchasers agreed to amend and restate 2,941,178 of each the Series A common stock warrants and Series B common stock warrants outstanding, by reducing the exercise price thereunder from $1.11 to $0.77 per share. Pursuant to ASU 2021-04, the Company remeasured the fair value of the amended and restated Prior Warrants as of the modification date based on the modified terms and recorded the increase in fair value of $0.3 million as equity issuance costs, all of which was allocated to additional paid in capital. The fair value assumptions related to the modification of these 5,882,356 amended and restated Prior Warrants as of January 17, 2024 were as follows: exercise price of $0.77 per share, stock price of $0.769 per share, expected life of 4.5 years, volatility of 96.91%, a risk-free rate of 4.02% and 0% expected dividend yield.

None of the January 2024 Pre-Funded Warrants have been exercised and all remained outstanding as of December 31, 2025.

July 2023 Private Placement Warrants

On July 20, 2023, the Company issued pre-funded warrants to purchase up to an aggregate of 2,012,356 shares of Common Stock at an exercise price of $0.001 per share, or the July 2023 Pre-Funded Warrants, the July 2023 Series A common stock warrants to purchase up to an aggregate of 7,352,947 shares of Common Stock at an exercise price of $1.11 per share, and the July 2023 Series B common stock warrants to purchase up to an aggregate of 7,352,947 shares of Common Stock at an exercise price of $1.11 per share.

The July 2023 Pre-Funded Warrants were exercisable immediately following the closing date of the July 2023 Private Placement, or July 20, 2023, and have an unlimited term.

The July 2023 Series A and Series B common stock warrants were exercisable immediately following the closing date of July 20, 2023, and have a five-year term, unless certain milestone events are met which accelerate the expiration date to 45 days following such announcement. The July 2023 Series A and Series B common stock warrants also include certain rights upon “fundamental transactions” as described in such warrants, including the right of the holders thereof to receive from the Company or a successor entity the same type or form of consideration (and in the same proportion) that is being offered and paid to the holders of Common Stock in such fundamental transaction in the amount of the Black Scholes value (as described in such warrants) of the unexercised portion of the applicable warrants on the date of the consummation of such fundamental transaction.

The Company evaluated the July 2023 Pre-Funded Warrants, and the July 2023 Series A and Series B common stock warrants under ASC 815-40 and determined that they did not require liability classification and met the requirements for instruments that are both indexed to an entity’s own stock and classified in stockholders’ equity. Accordingly, the proceeds were allocated between Common Stock and the July 2023 Pre-Funded Warrants, Series A and Series B common stock warrants at their respective relative fair value basis to stockholders’ equity and as a component of additional paid-in capital on the consolidated balance sheets. The fair value of the July 2023 Series A and Series B common stock warrants was determined using a Black-Scholes option pricing model and the Common Stock based on the closing date share price and were recorded in additional paid-in capital within stockholders' equity on the consolidated balance sheets.

In connection with the January 2024 Private Placement, the Company and the purchasers agreed to amend and restate the Prior Warrants by reducing their exercise price from $1.11 to $0.77 per share (see “January 2024 Pre-Funded Warrants and Amendment of Prior Warrants” above).

The placement agent July 2023 Series A and Series B Common Stock Warrants (see Note 8, “Stockholders’ Equity”) have the same terms as the July 2023 Series A and Series B Common Stock Warrants, except such warrants do not have a Black Scholes provision in the event of a fundamental transaction and the exercise price of such warrants is $1.70 per share, which is 125% of the combined offering price per share. The Company concluded that the placement agent July 2023 Series A and Series B Common Stock Warrants are freestanding equity-linked derivative instruments that met the criteria for equity classification. The placement agent July 2023 Series A and Series B Common Stock Warrants were valued at approximately $0.3 million, using the Black-Scholes option pricing model as follows: exercise price of $1.70 per share, stock price of $1.07 per share, expected life of 5 years, volatility of 94.3%, a risk-free rate of 4.08% and 0% expected dividend yield.

As of December 31, 2025, none of the July 2023 Series A and Series B common stock warrants nor the placement agent July 2023 Series A and Series B common stock warrants had been exercised and all were still outstanding, while 595,883 of the July 2023 Pre-Funded Warrants had been exercised, and 1,416,473 remained outstanding as of December 31, 2025.

December 2022 Registered Direct Offering Warrants

On December 29, 2022, the Company issued pre-funded warrants to purchase 2,632,898 shares of Common Stock, or the December 2022 Pre-Funded Warrants, and common warrants to purchase an aggregate of 4,227,052 shares of Common Stock, or the December 2022 Common Stock Warrants.

The December 2022 Pre-Funded Warrants were exercisable immediately following the closing date of the December 2022 Registered Direct Offering, or December 29, 2022, had an unlimited term and an exercise price of $0.0001 per share.

The December 2022 Common Stock Warrants were exercisable following the six-month anniversary of the closing date of December 29, 2022, have a six-year term and an exercise price of $2.07 per share. The 2022 Warrants included full ratchet anti-dilutive adjustment rights in the event the Company issued shares of Common Stock or common stock equivalents in the future with a value less than the then effective exercise price of such common warrants subject to certain customary exceptions, and further subject to a minimum exercise price of $1.00 per share. On April 25, 2023, the December 2022 Common Stock Warrants were amended to remove these full ratchet anti-dilutive adjustment rights.

In the event of certain fundamental transactions involving the Company, the holder of the December 2022 Common Stock Warrants may require the Company to make a payment based on a Black-Scholes valuation, using specified inputs. The December 2022 Pre-Funded Warrants did not provide similar rights to the Purchaser. Therefore, the Company accounted for the December 2022 Common Stock Warrants as a liability, while the December 2022 Pre-Funded Warrants met the permanent equity criteria classification. The December 2022 Pre-Funded Warrants were classified as a component of permanent equity, or APIC, because they were freestanding financial instruments that are legally detachable and separately exercisable from the shares of Common Stock with which they were issued, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, and permit the holders to receive a fixed number of shares of Common Stock upon exercise. In addition, the December 2022 Pre-Funded Warrants did not provide any guarantee of value or return.

As of December 31, 2025, none of the 4,227,052 December 2022 Common Stock Warrants had been exercised and all remained outstanding, while all of the 2,632,898 December 2022 Pre-Funded Warrants had been exercised in full and none remained outstanding at December 31, 2025.

August 2022 LPC Warrant

The August 2022 LPC Warrant had an original exercise price of $4.07 per share (subject to adjustment for stock splits, reverse stock splits and similar recapitalization events), became immediately exercisable and has a term ending on February 3, 2028. In addition, through August 3, 2023, if the Company issued or sold (or is deemed to have issued or sold) any Common Stock, convertible securities or options (as defined in the August 2022 LPC Warrant), for a consideration per share, or the New Issuance Price, less than a price equal to the exercise price in effect immediately prior to such issue or sale or deemed issuance or sale, each of the foregoing, a dilutive issuance, then immediately after such dilutive issuance, the exercise price then in effect for the August 2022 LPC Warrant shall be reduced to an amount equal to the New Issuance Price, or the Down Round Feature.

In December 2022, the Down Round Feature was triggered due to the price per share received from the issuance of Common Stock and warrants in connection with the December 2022 Financing. In July 2023, the Down Round Feature was again triggered due to the price per share received from the issuance of Common Stock and warrants in connection with the in connection with the July 2023 Private Placement. In each instance, the Company calculated the value of the effect of the Down Round Feature measured as the difference between the warrants’ fair value, using the Black-Scholes option-pricing model, before and after the Down Round Feature was triggered using the then current exercise price and the new exercise price. The difference in fair value of the effect of the Down Round Feature was immaterial in both instances and had no impact on net loss per share in the periods presented. This down round feature expired on August 3, 2023.

As of December 31, 2025, the August 2022 LPC Warrant had not been exercised and was still outstanding.

November 2021 Financing Warrants

On November 15, 2021, the Company entered into a securities purchase agreement with certain investors pursuant to which the Company, in a registered direct offering, sold (i) an aggregate of 875,000 shares of the Company’s common stock, and (ii) warrants to purchase up to an aggregate of 875,000 shares of Common Stock, for an aggregate purchase price of $14.0 million.

The November 2021 Financing Warrants had an original exercise price of $20.00 per share and became exercisable, if the holder’s post-exercise beneficial ownership is less than or equal to 9.99%, 6 months after their issuance date and had a five-year term through November 15, 2026. 

Upon the closing of the December 2022 Financing, 750,000 of the 875,000 November 2021 Financing Warrants were modified, to reduce the exercise price of the warrants from $20.00 per share to $2.07 per share and to extend the expiration date to December 29, 2028.

The remaining warrants issued in the November 17, 2021, registered direct offering for 125,000 shares of the Company’s common stock are currently exercisable at a price of $20.00 per share and expire on November 15, 2026.

As of December 31, 2025, none of the November 2021 Financing Warrants had been exercised and all remained outstanding.

Loan Agreement Warrants

In connection with the Loan Agreement, on May 30, 2019, the Company issued warrants to Oxford Finance LLC, or the Lender, which are exercisable for an aggregate of 8,833 shares of the Company’s common stock with a per share exercise price of $56.60, or the Loan Agreement Warrants. The Loan Agreement Warrants may be exercised on a cashless basis. The Loan Agreement Warrants are exercisable for a term beginning on the date of issuance and ending on the earlier to occur of ten years from the date of issuance or the consummation of certain acquisitions of the Company as set forth in the Loan Agreement Warrants. The number of shares for which the Loan Agreement Warrants are exercisable and the associated exercise price are subject to certain proportional adjustments as set forth in the Loan Agreement Warrants. The Loan Agreement Warrants have been classified within stockholders’ equity and accounted for as a discount to the loan by allocating the gross proceeds on a relative fair value basis.

As of December 31, 2025, none of the Loan Agreement Warrants had been exercised and all remained outstanding.