Subsequent Events	12 Months Ended
Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	12. SUBSEQUENT EVENTS Subsequent to December 31, 2022, the Company sold an aggregate of 1,462,254 shares of common stock under its ATM facility at an average gross sale price of $2.81 per share, resulting in gross proceeds of $4.1 million. Proceeds, net of $0.1 million of offering costs, were $4.0 million. On March 14, 2023, the Company granted options to acquire a total of 630,000 shares of its common stock to its directors, officers, and employees. Amendments to Borrowing Agreements On January 30, 2023, the Company entered into a Second Amendment (the “Second Amendment”) to the SWK Credit Agreement. In addition to other provisions, the Second Amendment provides for an additional senior secured term loan to be made to the Company in an aggregate amount of $7.0 million in a single borrowing which was funded on January 31, 2023 (the “Second Term Loan”, and together with the Original Term Loan, the “SWK Loans”). Pursuant to the terms of the August 2022 SWK Credit Agreement as amended by the Second Amendment (the “Current SWK Credit Agreement”): • Interest Rate: Interest is now calculated on the SWK Loans based on 3-month SOFR instead of 3-month LIBOR, such that the SWK Loans now bear interest at an annual rate of the sum of (i) 3-month SOFR, subject to a 1% floor, plus (ii) a margin of 11%, with such interest payable quarterly in arrears. • Capitalization of Interest: The Company’s option to capitalize accrued interest (the “PIK Amount”) has been extended through May 15, 2023 (instead of the previous February 15, 2023). • Maturity Date: The final maturity date of the Second Term Loan is March 4, 2024, which is the same as the final maturity date of the Original Term Loan. • Exit Fees: The Company has the option to prepay the Second Term Loan in whole or in part. Upon the repayment of the Second Term Loan (whether a voluntary prepayment, an accelerated repayment or at scheduled maturity), the Company must pay an exit fee so that SWK receives an aggregate amount (inclusive of all principal, interest and origination and other fees paid in cash to SWK under the SWK Credit Agreement with respect to the Second Term Loan, but excluding the Third Warrant (defined below)) equal to the outstanding principal amount of the Second Term Loan (inclusive of PIK Amounts) multiplied by: (i) if the repayment occurs on or before April 15, 2023, 1.18, (ii) if the repayment occurs on or after April 16, 2023 but prior to May 16, 2023, 1.28667, (iii) if the repayment occurs on or after May 16, 2023 but prior to June 16, 2023, 1.39334, and (iv) if the repayment occurs on or after July 16, 2023, 1.5. The Second Amendment did not modify the exit fee applicable to the Original Term Loan. • Minimum Cash Requirement: The Second Amendment revised the liquidity covenant and, due to topline results announced in March 2023 from the Company’s Phase 2a proof of concept clinical trial to evaluate ACER-801 as a potential treatment for moderate to severe VMS associated with menopause, , which showed that ACER-801 was safe and well-tolerated but did not achieve statistical significance when evaluating ACER-801’s ability to decrease the frequency or severity of hot flashes in postmenopausal women, the Current SWK Credit Agreement now provides that the Company’s cash and cash equivalents balance minus the aggregate amount of any accounts payable which are unpaid more than 90 days beyond terms consistent with the Company’s practice must not be less than the lesser of (a) the outstanding principal amount of the SWK Loans, or (b) $3.0 million (as opposed to $1.5 million for clause (b) prior to the announcement of such topline results). • Amortization: Due to topline results announced in March 2023 from the Company’s Phase 2a proof of concept clinical trial to evaluate ACER-801 as a potential treatment for moderate to severe VMS associated with menopause, the principal amount of the SWK Loans amortizes at a monthly rate of $0.6 million starting April 15, 2023, until the Company has issued additional equity or subordinated debt resulting in net cash proceeds of not less than $7.7 million (i.e., the sum of $10.0 million less the net In connection with the execution of the Second Amendment, the Company issued to SWK an additional warrant (the “Third Warrant”) to purchase 250,000 shares of the Company’s common stock at an exercise price of $2.39 per share. SWK may exercise the Third Warrant in accordance with the terms thereof for all or any part of such shares of common stock from the date of issuance until and including March 4, 2029. On January 30, 2023, the Company entered into an Amendment Agreement (the “Marathon Amendment Agreement”) with Marathon and Marathon Fund (i.e., the Holders) with respect to the Marathon Convertible Notes. Pursuant to the terms of the Marathon Amendment Agreement: • Each Holder agrees to defer payment by the Company of accrued and unpaid interest on their respective Marathon Convertible Note existing on the date of the Marathon Amendment Agreement through March 31, 2023, with such deferred interest, together with any accrued and unpaid interest on each Marathon Convertible Note incurred after March 31, 2023, to be due and payable in cash by the Company on April 15, 2023. • Each Marathon Convertible Note is amended with retroactive effect to delete the concept of a default rate of interest. • Each Marathon Convertible Note is amended to obligate the Company to repurchase such Marathon Convertible Note, on or before the fifth (5th) business day (but with five (5) business days’ notice) following the earlier of June 15, 2023 or the Company’s receipt of gross proceeds of at least $40.0 million from the issuance or sale of equity, debt and/or hybrid securities, loans or other financing on a cumulative basis since January 1, 2023 (excluding the Second Term Loan), at a price equal to 200% (the “Buy-Out Percentage”) of the outstanding principal amount of such Marathon Convertible Note, together with any accrued but unpaid interest thereon to the date of such repurchase; provided, that if the Company is prohibited from effectuating such repurchases pursuant to a subordination agreement with SWK, the Company shall cause the repurchase to occur on or before the fifth (5th) business day following the earlier of such prohibition being no longer applicable or the payment in full of all senior indebtedness described in such subordination agreement, but with five (5) business days’ notice; and provided, further, that if such repurchase has not occurred by April 15, 2023, the Buy-Out Percentage shall be increased by 2500 basis points for each 90-day period after April 15, 2023, pro-rated for the actual number of days elapsed in the 90-day period before repurchase actually occurs (for example, if the repurchase occurs on May 30, 2023, the Buy-Out Percentage shall be increased to 212.5%). With respect to the Credit Agreement, dated as of March 4, 2022, as amended by the Extension Agreement dated as of December 30, 2022 (as so amended, the “Marathon Term Credit Agreement”), among the Company, the Lenders party thereto (the “Lenders”) and Marathon, not individually, but solely in its capacity as administrative and collateral agent for the Lenders (the “Administrative Agent”), which provided for a senior secured term loan facility in an aggregate amount of up to $42.5 million in a single borrowing, the parties have entered into a Termination Agreement dated as of January 30, 2023 (the “Termination Agreement”). Pursuant to the Termination Agreement, the lending commitments of the Lenders are terminated without having been drawn upon, the Marathon Term Credit Agreement and all other loan documents entered into in connection therewith are terminated, and the Company agrees to pay the Administrative Agent a commitment fee of $0.6 million (which was earned as a result of the recent approval by the FDA of OLPRUVA™ for oral suspension in the U.S. for the treatment of certain patients living with urea cycle disorders involving deficiencies of carbamylphosphate synthetase, ornithine transcarbamylase, or argininosuccinic acid synthetase) and certain legal costs on the date on which the repurchase of the Marathon Convertible Notes occurs pursuant to the Marathon Amendment Agreement. Results from ACER-801 Phase 2a Trial The Company announced on March 17, 2023, that topline results from its Phase 2a proof of concept clinical trial to evaluate ACER-801 (osanetant) as a potential treatment for moderate to severe Vasomotor Symptoms (VMS) associated with menopause showed that ACER-801 was safe and well-tolerated but did not achieve statistical significance when evaluating ACER-801’s ability to decrease the frequency or severity of hot flashes in postmenopausal women. As a result, the Company announced it is pausing the ACER-801 program until it has conducted a thorough review of the full data set. Securities Purchase Agreement On March 21, 2023, the Company entered into a securities purchase agreement (the “Purchase Agreement”) with an institutional accredited investor (the “Purchaser”) pursuant to which the Company agreed to issue and sell, (i) in a registered direct offering, an aggregate of 2,335,000 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (“Common Stock”), and pre-funded warrants to purchase up to 585,306 shares of Common Stock (the “Pre-Funded Warrants”) at an exercise price of $0.001 per share, and (ii) in a concurrent private placement, warrants to purchase up to 2,920,306 shares of Common Stock (the “Common Warrants”) at an exercise price of $0.791 per share. Such registered direct offering and concurrent private placement are referred to herein as the “March 2023 Offering.” The combined purchase price for one Share and one Common Warrant was $0.916, and the combined purchase price for one Pre-Funded Warrant and one Common Warrant was $0.915. The March 2023 Offering was priced at-the-market under Nasdaq rules. The Company received aggregate gross proceeds from the Offering of approximately $2.7 million before deducting the placement agent fee (as described in greater detail below) and related offering expenses, resulting in net proceeds of approximately $2.3 million. The March 2023 Offering closed on March 24, 2023. The Purchase Agreement contains customary representations and warranties and agreements of the Company and the Purchaser and customary indemnification rights and obligations of the parties. Pursuant to the terms of the Purchase Agreement and subject to certain exceptions, the Company has agreed to certain restrictions on the issuance and sale of its Common Stock or Common Stock Equivalents (as defined in the Purchase Agreement) during the 30-day period following the closing of the March 2023 Offering. The Shares, the Pre-Funded Warrants and the shares of Common Stock issuable thereunder were offered by the Company pursuant to a registration statement on Form S-3 (File No. 333-261342), which was filed with the Securities and Exchange Commission (the “Commission”) on November 24, 2021 and was declared effective by the Commission on December 7, 2021 (the “Registration Statement”), and a prospectus supplement dated as of March 21, 2023. With respect to the Company’s amended and restated sales agreement dated March 18, 2020 (the “Sales Agreement”), with JonesTrading Institutional Services LLC and Roth Capital Partners, LLC (the “Agents”) relating to the offer and sale of Common Stock having an aggregate offering price of up to $50.0 million from time to time through or to the Agents acting as the Company’s sales agent or principal, pursuant to which the Company has filed with the Commission several prospectus supplements to the base prospectus included with the Registration Statement (the “Prospectuses”), in connection with the March 2023 Offering, the Company filed with the Commission a further prospectus supplement to suspend the Sales Agreement and terminate the continuous offering by the Company under the Prospectuses. The Common Warrants were offered in a private placement under Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), and, along with the shares of Common Stock underlying the Common Warrants, have not been registered under the Securities Act or applicable state securities laws. The Pre-Funded Warrants were offered, in lieu of shares of Common Stock, to any Purchaser whose purchase of shares of Common Stock and Common Warrants in the Offering would otherwise result in such Purchaser, together with its affiliates and certain related parties, beneficially owning more than 4.99% (or, at such Purchaser’s option upon issuance,9.99%) of the Company’s outstanding Common Stock immediately following the consummation of the Offering. Each Pre-Funded Warrant represents the right to purchase shares of Common Stock at an exercise price of $0.001 per share of Common Stock. The Pre-Funded Warrants are exercisable immediately and may be exercised at any time until the Pre-Funded Warrants are exercised in full, subject in each case to the beneficial ownership limitations set forth in the Pre-Funded Warrant. Each Common Warrant represents the right to purchase shares of Common Stock at an exercise price of $0.791 per share of Common Stock. The Common Warrants are exercisable immediately and have a term of five and one-half years from the issuance date, subject in each case to the beneficial ownership limitations set forth in the form of Common Warrant. The Company entered into an engagement letter with H.C. Wainwright & Co., LLC (“Wainwright”), pursuant to which Wainwright agreed to serve as the exclusive placement agent for the issuance and sale of securities of the Company pursuant to the Purchase Agreement. As compensation for such placement agent services, the Company has agreed to pay Wainwright a total cash fee equal to 7.5% of the aggregate gross proceeds of the Offering; a non-accountable expense allowance of $70,000 and clearing fees of $15,950. The Company has also granted Wainwright a right of first refusal for a period of six months following the closing of the Offering to act as sole book-running manager, sole underwriter or sole placement agent for any public or private placement or other capital-raising financing, subject to certain exceptions.

Subsequent to December 31, 2022, the Company sold an aggregate of 1,462,254 shares of common stock under its ATM facility at an average gross sale price of $2.81 per share, resulting in gross proceeds of $4.1 million. Proceeds, net of $0.1 million of offering costs, were $4.0 million.

On March 14, 2023, the Company granted options to acquire a total of 630,000 shares of its common stock to its directors, officers, and employees.

On January 30, 2023, the Company entered into a Second Amendment (the “Second Amendment”) to the SWK Credit Agreement. In addition to other provisions, the Second Amendment provides for an additional senior secured term loan to be made to the Company in an aggregate amount of $7.0 million in a single borrowing which was funded on January 31, 2023 (the “Second Term Loan”, and together with the Original Term Loan, the “SWK Loans”).

Pursuant to the terms of the August 2022 SWK Credit Agreement as amended by the Second Amendment (the “Current SWK Credit Agreement”):

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Exit Fees: The Company has the option to prepay the Second Term Loan in whole or in part. Upon the repayment of the Second Term Loan (whether a voluntary prepayment, an accelerated repayment or at scheduled maturity), the Company must pay an exit fee so that SWK receives an aggregate amount (inclusive of all principal, interest and origination and other fees paid in cash to SWK under the SWK Credit Agreement with respect to the Second Term Loan, but excluding the Third Warrant (defined below)) equal to the outstanding principal amount of the Second Term Loan (inclusive of PIK Amounts) multiplied by: (i) if the repayment occurs on or before April 15, 2023, 1.18, (ii) if the repayment occurs on or after April 16, 2023 but prior to May 16, 2023, 1.28667, (iii) if the repayment occurs on or after May 16, 2023 but prior to June 16, 2023, 1.39334, and (iv) if the repayment occurs on or after July 16, 2023, 1.5. The Second Amendment did not modify the exit fee applicable to the Original Term Loan.

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Minimum Cash Requirement: The Second Amendment revised the liquidity covenant and, due to topline results announced in March 2023 from the Company’s Phase 2a proof of concept clinical trial to evaluate ACER-801 as a potential treatment for moderate to severe VMS associated with menopause, , which showed that ACER-801 was safe and well-tolerated but did not achieve statistical significance when evaluating ACER-801’s ability to decrease the frequency or severity of hot flashes in postmenopausal women, the Current SWK Credit Agreement now provides that the Company’s cash and cash equivalents balance minus the aggregate amount of any accounts payable which are unpaid more than 90 days beyond terms consistent with the Company’s practice must not be less than the lesser of (a) the outstanding principal amount of the SWK Loans, or (b) $3.0 million (as opposed to $1.5 million for clause (b) prior to the announcement of such topline results).

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Amortization: Due to topline results announced in March 2023 from the Company’s Phase 2a proof of concept clinical trial to evaluate ACER-801 as a potential treatment for moderate to severe VMS associated with menopause, the principal amount of the SWK Loans amortizes at a monthly rate of $0.6 million starting April 15, 2023, until the Company has issued additional equity or subordinated debt resulting in net cash proceeds of not less than $7.7 million (i.e., the sum of $10.0 million less the net

In connection with the execution of the Second Amendment, the Company issued to SWK an additional warrant (the “Third Warrant”) to purchase 250,000 shares of the Company’s common stock at an exercise price of $2.39 per share. SWK may exercise the Third Warrant in accordance with the terms thereof for all or any part of such shares of common stock from the date of issuance until and including March 4, 2029.

On January 30, 2023, the Company entered into an Amendment Agreement (the “Marathon Amendment Agreement”) with Marathon and Marathon Fund (i.e., the Holders) with respect to the Marathon Convertible Notes.

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Each Holder agrees to defer payment by the Company of accrued and unpaid interest on their respective Marathon Convertible Note existing on the date of the Marathon Amendment Agreement through March 31, 2023, with such deferred interest, together with any accrued and unpaid interest on each Marathon Convertible Note incurred after March 31, 2023, to be due and payable in cash by the Company on April 15, 2023.

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Each Marathon Convertible Note is amended to obligate the Company to repurchase such Marathon Convertible Note, on or before the fifth (5th) business day (but with five (5) business days’ notice) following the earlier of June 15, 2023 or the Company’s receipt of gross proceeds of at least $40.0 million from the issuance or sale of equity, debt and/or hybrid securities, loans or other financing on a cumulative basis since January 1, 2023 (excluding the Second Term Loan), at a price equal to 200% (the “Buy-Out Percentage”) of the outstanding principal amount of such Marathon Convertible Note, together with any accrued but unpaid interest thereon to the date of such repurchase; provided, that if the Company is prohibited from effectuating such repurchases pursuant to a subordination agreement with SWK, the Company shall cause the repurchase to occur on or before the fifth (5th) business day following the earlier of such prohibition being no longer applicable or the payment in full of all senior indebtedness described in such subordination agreement, but with five (5) business days’ notice; and provided, further, that if such repurchase has not occurred by April 15, 2023, the Buy-Out Percentage shall be increased by 2500 basis points for each 90-day period after April 15, 2023, pro-rated for the actual number of days elapsed in the 90-day period before repurchase actually occurs (for example, if the repurchase occurs on May 30, 2023, the Buy-Out Percentage shall be increased to 212.5%).

With respect to the Credit Agreement, dated as of March 4, 2022, as amended by the Extension Agreement dated as of December 30, 2022 (as so amended, the “Marathon Term Credit Agreement”), among the Company, the Lenders party thereto (the “Lenders”) and Marathon, not individually, but solely in its capacity as administrative and collateral agent for the Lenders (the “Administrative Agent”), which provided for a senior secured term loan facility in an aggregate amount of up to $42.5 million in a single borrowing, the parties have entered into a Termination Agreement dated as of January 30, 2023 (the “Termination Agreement”). Pursuant to the Termination Agreement, the lending commitments of the Lenders are terminated without having been drawn upon, the Marathon Term Credit Agreement and all other loan documents entered into in connection therewith are terminated, and the Company agrees to pay the Administrative Agent a commitment fee of $0.6 million (which was earned as a result of the recent approval by the FDA of OLPRUVA™ for oral suspension in the U.S. for the treatment of certain patients living with urea cycle disorders involving deficiencies of carbamylphosphate synthetase, ornithine transcarbamylase, or argininosuccinic acid synthetase) and certain legal costs on the date on which the repurchase of the Marathon Convertible Notes occurs pursuant to the Marathon Amendment Agreement.

The Company announced on March 17, 2023, that topline results from its Phase 2a proof of concept clinical trial to evaluate ACER-801 (osanetant) as a potential treatment for moderate to severe Vasomotor Symptoms (VMS) associated with menopause showed that ACER-801 was safe and well-tolerated but did not achieve statistical

significance when evaluating ACER-801’s ability to decrease the frequency or severity of hot flashes in postmenopausal women. As a result, the Company announced it is pausing the ACER-801 program until it has conducted a thorough review of the full data set.

On March 21, 2023, the Company entered into a securities purchase agreement (the “Purchase Agreement”) with an institutional accredited investor (the “Purchaser”) pursuant to which the Company agreed to issue and sell, (i) in a registered direct offering, an aggregate of 2,335,000 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (“Common Stock”), and pre-funded warrants to purchase up to 585,306 shares of Common Stock (the “Pre-Funded Warrants”) at an exercise price of $0.001 per share, and (ii) in a concurrent private placement, warrants to purchase up to 2,920,306 shares of Common Stock (the “Common Warrants”) at an exercise price of $0.791 per share. Such registered direct offering and concurrent private placement are referred to herein as the “March 2023 Offering.” The combined purchase price for one Share and one Common Warrant was $0.916, and the combined purchase price for one Pre-Funded Warrant and one Common Warrant was $0.915. The March 2023 Offering was priced at-the-market under Nasdaq rules. The Company received aggregate gross proceeds from the Offering of approximately $2.7 million before deducting the placement agent fee (as described in greater detail below) and related offering expenses, resulting in net proceeds of approximately $2.3 million. The March 2023 Offering closed on March 24, 2023.

The Purchase Agreement contains customary representations and warranties and agreements of the Company and the Purchaser and customary indemnification rights and obligations of the parties. Pursuant to the terms of the Purchase Agreement and subject to certain exceptions, the Company has agreed to certain restrictions on the issuance and sale of its Common Stock or Common Stock Equivalents (as defined in the Purchase Agreement) during the 30-day period following the closing of the March 2023 Offering.

The Shares, the Pre-Funded Warrants and the shares of Common Stock issuable thereunder were offered by the Company pursuant to a registration statement on Form S-3 (File No. 333-261342), which was filed with the Securities and Exchange Commission (the “Commission”) on November 24, 2021 and was declared effective by the Commission on December 7, 2021 (the “Registration Statement”), and a prospectus supplement dated as of March 21, 2023. With respect to the Company’s amended and restated sales agreement dated March 18, 2020 (the “Sales Agreement”), with JonesTrading Institutional Services LLC and Roth Capital Partners, LLC (the “Agents”) relating to the offer and sale of Common Stock having an aggregate offering price of up to $50.0 million from time to time through or to the Agents acting as the Company’s sales agent or principal, pursuant to which the Company has filed with the Commission several prospectus supplements to the base prospectus included with the Registration Statement (the “Prospectuses”), in connection with the March 2023 Offering, the Company filed with the Commission a further prospectus supplement to suspend the Sales Agreement and terminate the continuous offering by the Company under the Prospectuses.

The Common Warrants were offered in a private placement under Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), and, along with the shares of Common Stock underlying the Common Warrants, have not been registered under the Securities Act or applicable state securities laws.

The Pre-Funded Warrants were offered, in lieu of shares of Common Stock, to any Purchaser whose purchase of shares of Common Stock and Common Warrants in the Offering would otherwise result in such Purchaser, together with its affiliates and certain related parties, beneficially owning more than 4.99% (or, at such Purchaser’s option upon issuance,9.99%) of the Company’s outstanding Common Stock immediately following the consummation of the Offering. Each Pre-Funded Warrant represents the right to purchase shares of Common Stock at an exercise price of $0.001 per share of Common Stock. The Pre-Funded Warrants are exercisable immediately and may be exercised at any time until the Pre-Funded Warrants are exercised in full, subject in each case to the beneficial ownership limitations set forth in the Pre-Funded Warrant.

Each Common Warrant represents the right to purchase shares of Common Stock at an exercise price of $0.791 per share of Common Stock. The Common Warrants are exercisable immediately and have a term of five

and one-half years from the issuance date, subject in each case to the beneficial ownership limitations set forth in the form of Common Warrant.

The Company entered into an engagement letter with H.C. Wainwright & Co., LLC (“Wainwright”), pursuant to which Wainwright agreed to serve as the exclusive placement agent for the issuance and sale of securities of the Company pursuant to the Purchase Agreement. As compensation for such placement agent services, the Company has agreed to pay Wainwright a total cash fee equal to 7.5% of the aggregate gross proceeds of the Offering; a non-accountable expense allowance of $70,000 and clearing fees of $15,950. The Company has also granted Wainwright a right of first refusal for a period of six months following the closing of the Offering to act as sole book-running manager, sole underwriter or sole placement agent for any public or private placement or other capital-raising financing, subject to certain exceptions.