Aceragen (ACGN) 10-Q 29 Jun 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Jun. 29, 2023
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2023
Entity File Number	001-31918
Entity Registrant Name	Aceragen, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3072298
Entity Address, Address Line One	505 Eagleview Blvd., Suite 212
Entity Address, City or Town	Exton
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19341
City Area Code	484
Local Phone Number	348-1600
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	ACGN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		8,423,504
Entity Central Index Key	0000861838
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 2,118	$ 12,044
Accounts receivable	2,203	4,208
Prepaid expenses and other current assets	1,315	1,611
Total current assets	5,636	17,863
Property and equipment, net	4	7
Intangible assets	67,000	71,600
Goodwill	4,629	11,100
Operating lease right-of-use assets	471	537
Other assets	752
Total assets	78,492	101,107
Current liabilities:
Accounts payable	3,409	5,200
Accrued expenses	7,198	9,911
Acquisition obligation, net	6,300	6,078
Operating lease liability	223	234
Other current liability	733
Total current liabilities	17,863	21,423
Warrant liability		2,819
Series X preferred stock liability (includes 5 shares of Series X convertible preferred stock, $0.01 par value per share issued and outstanding as December 31, 2022 - Note 6)	34,800	34,300
Operating lease liability, net of current portion	271	326
Deferred tax liability	3,010	3,283
Other liabilities		22
Total liabilities	55,944	62,173
Commitments and contingencies
Stockholders' equity:
Preferred stock
Common stock, $0.001 par value, Authorized - 140,000,000 shares; Issued and outstanding - 8,346,949 and 3,653,685 shares at March 31, 2023 and December 31, 2022, respectively	8	4
Additional paid-in capital	803,251	770,663
Accumulated deficit	(780,688)	(758,821)
Accumulated other comprehensive income (loss)	(23)	(21)
Total stockholders' equity	22,548	11,826
Total liabilities, convertible redeemable preferred stock, and stockholders' equity	78,492	101,107
Series A convertible preferred stock
Stockholders' equity:
Preferred stock
Series Z convertible preferred stock
Current liabilities:
Preferred stock, $0.01 par value, Authorized - 5,000,000 shares: Series Z convertible redeemable preferred stock (Note 8); Designated - 150,000 shares, Issued and outstanding - 0 and 77,900 shares at March 31, 2023 and December 31, 2022, respectively		27,108
Series B1 convertible preferred stock
Stockholders' equity:
Preferred stock		$ 1

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	140,000,000	140,000,000
Common stock, shares issued	8,346,949	3,653,685
Common stock, shares outstanding	8,346,949	3,653,685
Series A convertible preferred stock
Preferred stock, shares designated	1,500,000	1,500,000
Preferred stock, shares issued	655	655
Preferred stock, shares outstanding	655	655
Series B Preferred Stock
Preferred stock, shares designated	200,000	200,000
Preferred stock, shares issued	0	62,355
Preferred stock, shares outstanding	0	62,355
Series X convertible preferred stock
Preferred stock liability, par value		$ 0.01
Preferred stock liability, shares issued		5
Preferred stock liability, shares outstanding		5
Series Z convertible preferred stock
Temporary equity, preferred stock, par value	$ 0.01	$ 0.01
Temporary Equity, preferred stock, shares authorized	5,000,000	5,000,000
Temporary Equity, preferred stock, shares designated	150,000	150,000
Temporary Equity, preferred stock, shares issued	0	77,900
Temporary Equity, preferred stock, shares outstanding	0	77,900

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED)
Government contracts revenue	$ 2,470	$ 0
Revenue, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember
Operating expenses:
Research and development	$ 4,993	$ 1,784
General and administrative	4,920	2,398
Goodwill and intangible assets impairment	11,071
Restructuring and other costs	1,300
Acquisition-related costs	794
Total operating expenses	23,078	4,182
Loss from operations	(20,608)	(4,182)
Other income (expense):
Interest income (expense), net	(185)	3
Warrant revaluation loss	(874)
Series X preferred stock liability loss	(500)
Foreign currency exchange and other gain (loss), net	27	1
Loss before income tax benefit	(22,140)	(4,178)
Income tax benefit	273	0
Net loss	$ (21,867)	$ (4,178)
Net loss per share applicable to common stockholders
- Basic	$ (2.94)	$ (1.34)
- Diluted	$ (2.94)	$ (1.34)
Weighted-average number of common shares used in computing net loss per share applicable to common stockholders
- Basic	7,448,799	3,111,354
- Diluted	7,448,799	3,111,354
Comprehensive loss:
Net loss	$ (21,867)	$ (4,178)
Other comprehensive income (loss), net of tax:
Foreign currency translation	(2)
Total other comprehensive (loss) income, net of tax	(2)
Total comprehensive loss	$ (21,869)	$ (4,178)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash Flows from Operating Activities:
Net loss	$ (21,867)	$ (4,178)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,231	545
Foreign currency translation	(9)
Goodwill and intangible assets impairment	11,071
Warrant revaluation loss	874
Series X preferred stock liability loss	500
Issuance of common stock for services rendered	15	22
Accretion of discounts on acquisition obligation	222
Depreciation and amortization expense	3	4
Deferred tax benefit	(273)
Changes in operating assets and liabilities
Accounts receivable	2,005
Prepaid expenses and other assets	449	124
Accounts payable, accrued expenses, and other liabilities	(3,826)	(1,086)
Other	(247)	1
Net cash used in operating activities	(9,852)	(4,568)
Cash Flows from Financing Activities:
Proceeds from employee stock purchases		16
Proceeds from exercise of stock options	88
Payments on seller-financed purchases	(170)
Other	8
Net cash (used in) provided by financing activities	(74)	16
Net decrease in cash and cash equivalents	(9,926)	(4,552)
Cash and cash equivalent, beginning of period	12,044	32,545
Cash and cash equivalents, end of period	2,118	27,993
Supplemental disclosure of cash flow information:
Cash paid for interest		5
Supplemental disclosure of non-cash financing and investing activities:
Offering costs in accrued expenses		$ 15
Non-cash seller-financed purchases	$ 903

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Common Stock	Preferred Stock Series Z preferred stock	Preferred Stock Series B Preferred Stock	Additional Paid-In Capital	Accumulated Deficit	Other Comprehensive Income (Loss)	Total
Beginning balance at Dec. 31, 2021	$ 3			$ 764,911	$ (735,461)		$ 29,453
Beginning balance (in shares) at Dec. 31, 2021	3,106,947
Increase (Decrease) in Stockholders' Equity
Sale of common stock, net of issuance costs				(15)			(15)
Issuance of common stock under employee stock purchase plan				16			16
Issuance of common stock under employee stock purchase plan (in shares)	2,482
Issuance of common stock under equity incentive plan upon vesting of restricted stock units (in shares)	1,600
Issuance of common stock for services rendered				22			22
Issuance of common stock for services rendered (in shares)	2,180
Stock-based compensation expense				545			545
Net loss					(4,178)		(4,178)
Ending balance at Mar. 31, 2022	$ 3			765,479	(739,639)		25,843
Ending balance (in shares) at Mar. 31, 2022	3,113,209
Temporary equity, Beginning balance at Dec. 31, 2022		$ 27,108
Temporary equity, Beginning balance (in shares) at Dec. 31, 2022		77,900
Increase (Decrease) in Temporary Equity
Vesting of restricted stock awards (in shares)		47
Conversion of preferred stock to common stock		$ (27,108)
Conversion of preferred stock to common, shares		(77,947)
Beginning balance at Dec. 31, 2022	$ 4		$ 1	770,663	(758,821)	$ (21)	$ 11,826
Beginning balance at Dec. 31, 2022			62,355
Beginning balance (in shares) at Dec. 31, 2022	3,653,685						3,653,685
Increase (Decrease) in Stockholders' Equity
Vesting of restricted stock awards (in shares)	6,386
Issuance of common stock under equity incentive plan upon vesting of restricted stock units and exercise of options				88			$ 88
Issuance of common stock under equity incentive plan upon vesting of restricted stock units and exercise of options (in shares)	55,891
Issuance of common stock under equity incentive plan for retention payments				456			456
Issuance of common stock under equity incentive plan for retention payments (in shares)	43,900
Issuance of common stock for services rendered				15			15
Issuance of common stock for services rendered (in shares)	1,972
Conversion of preferred stock to common stock	$ 4		$ (1)	27,105			27,108
Conversion of preferred stock to common stock (in shares)	4,585,115		(62,355)
Reclassification of warrant liability upon conversion of Series Z Preferred Stock warrants to common stock warrants				3,693			3,693
Stock-based compensation expense				1,231			1,231
Foreign currency translation						(2)	(2)
Net loss					(21,867)		(21,867)
Ending balance at Mar. 31, 2023	$ 8			$ 803,251	$ (780,688)	$ (23)	$ 22,548
Ending balance (in shares) at Mar. 31, 2023	8,346,949						8,346,949

Business and Organization

Business and Organization	3 Months Ended
	Mar. 31, 2023
Business and Organization
Business and Organization	Note 1. Business and Organization ​ Business Overview ​ Aceragen, Inc. (“Aceragen” or the “Company”) (f/k/a Idera Pharmaceuticals, Inc. (“Idera”)), a Delaware corporation, is a clinical-stage biopharmaceutical company with a business strategy originally focused on the clinical development, and ultimately the commercialization, of drug candidates for rare disease indications characterized by small, well-defined patient populations with serious unmet medical needs. ​ On September 28, 2022 (the “Effective Date”), Idera acquired Aceragen, Inc. and its wholly owned subsidiaries (“Legacy Aceragen”), in accordance with the terms of the Agreement and Plan of Merger, dated as of the Effective Date (the “Merger Agreement”). Legacy Aceragen was a privately-held biotechnology company addressing severe, rare, and orphan pulmonary and rheumatic diseases for which there are limited or no available treatments. The Company acquired Legacy Aceragen as a strategic extension of its rare disease business and focus with the primary objective of further developing Legacy Aceragen’s portfolio of rare disease product candidates. ​ Following the Special Meeting of Stockholders held on January 12, 2023 (the “Special Meeting”), Idera’s name was changed to Aceragen, Inc. (the “Merger” and, together with the other transactions contemplated by the Merger Agreement, the “Aceragen Acquisition”). See Note 3, “Business Acquisition,” f ​ Presently, the Board of Directors of the Company (the “Board”) is evaluating several options, including an assignment for the benefit of creditors, wind-down, or liquidation and dissolution. ​ Liquidity, Financial Condition and Consideration as a Going Concern ​ The Company follows the provisions of Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 205-40, Presentation of Financial Statements—Going Concern ​ The Company has incurred substantial losses and negative cash flows from operations since its inception and had an accumulated deficit of $780.7 million as of March 31, 2023. The Company’s cash and cash equivalents balance of $2.1 million as of March 31, 2023 is not sufficient to fund its operations for the one-year period after the date that the condensed consolidated financial statements were issued. These factors raise substantial doubt about the Company’s ability to continue as a going concern. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. The condensed consolidated financial statements do not include any adjustments related to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty. ​ Funding for Future Operations ​ Management has evaluated different strategies to obtain the required funding for future operations. Despite its efforts, the Company has been unsuccessful in securing additional capital to fund operations, restructure its outstanding debt and otherwise satisfy creditor obligations. As further discussed in Note 15, on April 28, 2023, the Company’s Board of Directors (the “Board”) approved a reduction in workforce in which approximately 80% of the Company’s employees were terminated, effective immediately. This reduction in workforce required the Company to cease development of ACG-701 (patented formulation of sodium fusidate) for Cystic Fibrosis Pulmonary Exacerbations and ACG-801 (recombinant human acid ceramidase (rhAC)) for Farber Disease. Currently, the Company continues to develop only ACG-701 for Melioidosis subsequent to the reduction in workforce. ​ As a result, management and the Board are evaluating an assignment for benefit of creditors and other strategic alternatives that may be available, including bankruptcy and liquidation of the Company. NovaQuest ​ Pursuant to the Stock and Warrant Purchase Agreement, dated as of March 24, 2021, by and between Legacy Aceragen and NovaQuest Co-Investment Fund XV, L.P. (“NovaQuest”), as amended by that Amendment, dated October 25, 2021, and as such agreement may be amended from time to time (the “Purchase Agreement”), NovaQuest agreed to provide up to ​ Subsequent to the Company’s cessation of development efforts around ACG-801, NovaQuest has alleged that the Company is in breach of the Purchase Agreement and is demanding the return of $35.0 million, plus 12% interest compounded annually and accruing from March 24, 2021 until paid. The Company is currently negotiating with NovaQuest with respect to the Purchase Agreement, however, there is no assurance that such negotiations will be successful. ​ Reverse Stock Split ​ On January 17, 2023, the Company effected a 1 -for-17 reverse stock split of the Company's outstanding shares of common stock, as approved by the Company’s stockholders at the Special Meeting. All share and per share amounts of common stock, options, warrants, restricted stock, restricted stock units, and conversion ratio of convertible preferred stock and convertible preferred stock warrants in the accompanying condensed consolidated financial statements and notes thereto have been retroactively adjusted for all periods presented to reflect the reverse stock split.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies ​ Basis of Presentation ​ The accompanying unaudited condensed consolidated financial statements included herein have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the SEC. Accordingly, certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three months ended March 31, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s 2022 Form 10-K filed with the SEC. ​ Financial Instruments ​ The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 4. The Company is required to disclose the estimated fair values of its financial instruments. As of March 31, 2023 and December 31, 2022, the Company’s financial instruments included cash and cash equivalents, accounts receivable, accounts payable, Acquisition Obligation (defined below), and Series X Preferred Stock and Series Z Preferred Stock Warrant liabilities. The carrying amount of cash and cash equivalents, accounts receivable, and accounts payable approximates fair value due to the short-term maturities of these instruments. The carrying values of the Acquisition Obligation (defined below), Series X Preferred Stock liability and Series Z Preferred Stock Warrants liability are recorded at their estimated fair values. As of March 31, 2023, the Company did not have any other derivatives, hedging instruments or other similar financial instruments. ​ ​ Concentration of Credit Risk ​ Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash, which, at times, may exceed federally insured limits, and cash equivalents consisting of investments in money market funds managed by a variety of financial institutions. The Company's credit risk is managed by investing in only highly rated money market instruments. As a result, no significant additional credit risk is believed by management to be inherent in the Company’s assets and the Company has not experienced any losses in such accounts and believes it is not exposed to any significant risk on such accounts. ​ Business Combinations ​ The Company evaluates acquisitions of assets and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs, which would meet the requirements of a business. If determined to be a business combination, the Company accounts for the transaction under the acquisition method of accounting as indicated in ASU 2017-01, Business Combinations (ASC 805) Business Combinations ​ Cash and Cash Equivalents ​ The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at March 31, 2023 and December 31, 2022 consisted of cash and money market funds. ​ Accounts Receivable ​ The U.S. Government accounted for all of the Company’s accounts receivable as of March 31, 2023. Accordingly, the Company does not expect any credit losses with respect to its accounts receivable and no credit losses have been incurred to date. Included in accounts receivable at March 31, 2023 is $0.3 million of unbilled receivables which relates to revenue recognized for work that has been performed but the invoicing has not yet occurred as of the reporting date. ​ Indefinite-Lived Intangible Assets ​ Indefinite-lived intangible assets consist of In-Process Research and Development (“IPR&D”). The fair values of IPR&D project assets acquired in business combinations are capitalized. The Company generally utilizes the Multi-Period Excess Earning Method to determine the estimated fair value of the IPR&D assets acquired in a business combination. The projections used in this valuation approach are based on many factors, such as relevant market size, the estimated probability of regulatory success rates, anticipated patent protection, expected pricing, expected treated population, and estimated payments (e.g., royalty). The estimated future net cash flows are then discounted to the present value using an appropriate discount rate. These assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are amortized over the remaining useful life or written off, as appropriate. ​ Intangible assets with indefinite lives, including IPR&D, are tested for impairment if impairment indicators arise and, at a minimum, annually. However, an entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that an indefinite-lived intangible asset’s fair value is less than its carrying amount. Otherwise, no further impairment testing is required. The indefinite-lived intangible asset impairment test consists of a one-step analysis that compares the fair value of the intangible asset with its carrying amount. If the carrying amount of an intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. The Company considers many factors in evaluating whether the value of our intangible assets with indefinite lives may not be recoverable, including, but not limited to, expected growth rates, the cost of equity and debt capital, general economic conditions, our outlook and market performance of the Company’s industry and recent and forecasted financial performance. ​ The Company evaluates indefinite-lived intangible assets for impairment at least annually on October 1 and whenever facts and circumstances indicate that their carrying amounts may not be recoverable. During the three months ended March 31, 2023, management identified an indicator of impairment related to the decrease in the Company’s market capitalization. As a result, the Company performed an interim impairment test that resulted in the recognition of an impairment loss of $4.6 million related to IPR&D (see Note 3 and 4 for further discussion). ​ Goodwill ​ Goodwill represents the amount of consideration paid in excess of the fair value of net assets acquired as a result of the Company’s business acquisitions accounted for using the acquisition method of accounting. The intangible assets acquired represented the fair value of IPR&D which has been recorded on the accompanying condensed consolidated balance sheet as indefinite-lived intangible assets. A deferred tax liability was recorded for the difference between the fair value of the acquired IPR&D and its tax basis which was recognized as goodwill in applying the purchase method of accounting. Goodwill is not amortized and is subject to impairment testing at a reporting unit level on an annual basis or when a triggering event occurs that may indicate the carrying value of the goodwill is impaired. An entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that the fair value of the reporting unit is less than its carrying amount. ​ The Company evaluates goodwill for impairment at least annually on October 1 and whenever facts and circumstances indicate that the carrying amount of the reporting unit is greater than its fair value. During the three months ended March 31, 2023, management identified an indicator of impairment related to the decrease in the Company’s market capitalization. As a result, the Company performed an interim impairment test that resulted in the recognition of an impairment loss of $6.5 million related to goodwill (see Note 3 and 4 for further discussion). ​ Operating Lease Right-of-use Asset and Lease Liability ​ The Company accounts for leases under ASC 842, Leases. Operating leases are included in “Operating lease right-of-use assets” within the Company’s condensed consolidated balance sheets and represent the Company’s right to use an underlying asset for the lease term. The Company’s related obligation to make lease payments are included in “Operating lease liability” and “Operating lease liability, net of current portion” within the Company’s condensed consolidated balance sheets. Operating lease right-of-use (“ROU”) assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The ROU assets are tested for impairment according to ASC 360, Property, Plant, and Equipmen ​ As of March 31, 2023 and December 31, 2022, the Company’s operating lease ROU assets and corresponding short-term and long-term lease liabilities primarily relate to its existing Exton, PA facility operating lease, which expires on May 31, 2025. In connection with the Aceragen Acquisition, the Company acquired an operating lease for an office in Basel, Switzerland, which expired on March 31, 2023. ​ Impairment of Long-Lived Assets ​ In accordance with ASC 360-10-35, Impairment or Disposal of Long-Lived Assets among other things, depreciation and obsolescence. Fair value, utilizing the market approach, benchmarks the fair value against the carrying amount. ​ Other Current Liability ​ In January 2023, the Company entered into a short-term financing arrangement with a third-party vendor to finance insurance premiums. The aggregate amount financed under this agreement was $0.9 million. As of March 31, 2023, the balance of $0.7 million, which is included in “Other current liability’ in the Company’s condensed consolidated balance sheets, is scheduled to be paid in monthly installments through August 2023. Total interest to be incurred under the financing arrangement is not material. ​ Warrant Liability ​ The Company accounts for stock warrants as either equity instruments, liabilities or derivative liabilities in accordance with ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging ​ In connection with the Aceragen Acquisition, a portion of the consideration paid to Legacy Aceragen warrant holders was in the form of warrants to purchase shares of Series Z Preferred Stock (“Series Z Warrants”). Such warrants were classified as liabilities upon issuance and as of December 31, 2022 because the underlying Series Z Preferred Stock is contingently redeemable. During the three months ended March 31, 2023, all of the Company’s liability-classified Series Z Warrants were converted into warrants to purchase common stock and, accordingly, the Series Z Warrant liability was reclassified to stockholders’ equity. ​ Redeemable Preferred Stock ​ The Company applies ASC 480 when determining the classification and measurement of its preferred stock. Preferred shares subject to mandatory redemption are classified as liability instruments and are measured at fair value. Conditionally redeemable preferred shares (including preferred shares that feature redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control) are classified as temporary equity. At all other times, preferred shares are classified as stockholders’ equity. ​ Series X Preferred Stock Liability ​ In conjunction with the Aceragen Acquisition, the Company evaluated the newly issued Series X Preferred Stock and determined its revised terms represents a sale of future revenues and is classified as a liability under ASC 470, Debt ​ ​ Revenue Recognition ​ The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers ​ Government Contract Revenue ​ Revenues from reimbursable contracts are recognized as costs are incurred, generally based on allowable direct costs incurred during the period, plus allocable overheads together with any recognizable earned fee. The Company uses this output method to measure progress as the customer has access to the development research under these projects and benefits incrementally as research and development activities occur. ​ See Note 10, “Government Contracts Revenue,” of the notes to these condensed consolidated financial statements for discussion of the Company’s cost reimbursement contracts. ​ Customer Concentration Risk ​ The U.S. Government accounted for all of the Company’s revenues for the three months ended March 31, 2023. ​ Goodwill and Intangible Assets Impairment ​ The Company incurred total impairment losses of $11.1 million during the three months ended March 31, 2023, consisting of impairment losses of its IPR&D and goodwill totaling $4.6 million and $6.5 million, respectively, as more fully described above. ​ Restructuring and Other Costs ​ In connection with the Aceragen Acquisition, the Company determined to restructure its operations and reduce its workforce which resulted in seven positions being eliminated by December 31, 2022, representing approximately 54% of the Company’s pre-Aceragen Acquisition employees. As a result of the above restructuring initiatives, the Company incurred total restructuring-related charges of $5.0 million to date, including $1.3 million during the three months ended March 31, 2023 related to severance payments to two former executives which were contingent on obtaining shareholder approval at the Special Meeting, which occurred in January 2023. Such amounts are payable in stock and are included in accrued expenses as of March 31, 2023. ​ As of March 31, 2023, of the $5.0 million total restructuring-related charges incurred, $3.4 million remain unpaid and are included in accrued expenses in the accompanying condensed consolidated balance sheet. See Note 5. ​ Acquisition-Related Costs ​ Acquisition-related costs include direct expenses incurred in connection with the Aceragen Acquisition, as well as integration-related professional fees, employee retention-related benefits, and other incremental costs directly associated to the Aceragen Acquisition. For the three months ended March 31, 2023 acquisition-related costs totaled $0.8 million. ​ Income Taxes ​ In accordance with ASC 270, Interim Reporting Income Taxes acquired in connection with the Aceragen Acquisition the recognition of an impairment loss on such IPR&D assets (see Note 4) and reevaluation of the realizability of the Company’s deferred tax assets. No such income tax benefit (or expense) was recorded during the three months ended March 31, 2022. Net Loss per Common Share Applicable to Common Stockholders ​ The Company uses the two-class method to compute net income per common share during periods the Company realizes net income and has securities outstanding (e.g., redeemable convertible preferred stock) that entitle the holder to participate in dividends and earnings of the Company. In addition, the Company analyzes the potential dilutive effect of outstanding redeemable convertible preferred stock under the "if-converted" method when calculating diluted earnings per share and reports the more dilutive of the approaches (two class or "if-converted"). The two-class method is not applicable during periods with a net loss, as the holders of the redeemable convertible preferred stock have no obligation to fund losses. The Company also analyzes the potential dilutive effect of outstanding stock options, unvested restricted stock and restricted stock units, and warrants under the treasury stock method (as applicable), during periods of income, or during periods in which income is recognized related to changes in fair value of its liability-classified securities. ​ New Accounting Pronouncements ​ From time to time, new accounting pronouncements are issued by the FASB and rules are issued by the SEC that the Company has or will adopt as of a specified date. Unless otherwise noted, management does not believe that any other recently issued accounting pronouncements issued by the FASB or guidance issued by the SEC had, or is expected to have, a material impact on the Company’s present or future consolidated financial statements.

Business Acquisition

Business Acquisition	3 Months Ended
	Mar. 31, 2023
Business Acquisition
Business Acquisition	Note 3. Business Acquisition ​ On the Effective Date, and in accordance with the terms of the Merger Agreement, the Company acquired 100% of the outstanding security interests of Legacy Aceragen in a “stock-for-stock” transaction whereby all Legacy Aceragen outstanding equity interests were exchanged for a combination of shares of Company common stock, shares of Series Z Preferred Stock, and shares of the newly designated Series X non-voting preferred stock, par value $0.01 per share (“Series X Preferred Stock”). Under the terms of the Merger Agreement, Legacy Aceragen stockholders received (i) 451,608 shares of the Company’s common stock (inclusive of unvested restricted common stock – see Note 12), (ii) 80,656 shares of Series Z Preferred Stock (inclusive of unvested restricted preferred stock – see Note 12) and (iii) five shares of Series X Preferred Stock. In addition, all outstanding options and warrants to purchase Legacy Aceragen common stock were assumed by the Company and converted into stock options and warrants to purchase shares of the Company’s common stock and Series Z Preferred Stock on terms substantially identical to those in effect prior to the Aceragen Acquisition, except for adjustments to the underlying number of shares and the exercise price based on the Merger Agreement exchange ratio. The Aceragen Acquisition was unanimously approved by the Board and the board of directors of Legacy Aceragen. The closing of the transaction was not subject to the approval of the Company’s stockholders. ​ Pursuant to the Merger Agreement, at the Special Meeting the Company’s stockholders approved, among other matters: (i) the conversion of Series Z Preferred Stock into shares of common stock in accordance with Nasdaq Listing Rule 5635(a) (the “Conversion Proposal”) and (ii) a proposal to amend the Company’s Restated Certificate of Incorporation to effect a reverse stock split of all of the Company’s issued and outstanding shares of common stock (the “Reverse Stock Split Proposal” and, together with the Conversion Proposal, the “Merger Agreement Meeting Proposals”). ​ The transaction was accounted for under the acquisition method of accounting. Under the acquisition method, the total purchase price of the acquisition is allocated to the net tangible and identifiable intangible assets acquired and liabilities assumed based on the fair values as of the date of the acquisition. Consideration paid is comprised of the estimated fair value of various securities issued including the Series Z Preferred Stock, Series X Preferred Stock, stock options, restricted stock and warrants issued to Legacy Aceragen shareholders. The fair value of the consideration totaled approximately $65.6 million, summarized as follows: ​ ​ ​ ​ ​ (In thousands) ​ Common stock issued to Aceragen stockholders ​ $ 2,809 Series Z issued to Aceragen stockholders (Note 8) ​ 25,085 Series X liability in connection with Aceragen Acquisition (Note 6) ​ ​ 31,900 Stock options, restricted stock and warrants allocated to consideration paid ​ 5,822 Total Consideration paid ​ $ 65,616 ​ The Company recorded the assets acquired and liabilities assumed as of the date of the Aceragen Acquisition based on the information available at that date. The following table presents the allocation of the purchase price to the estimated fair values of the assets acquired and liabilities assumed as of the Aceragen Acquisition date: ​ ​ ​ ​ ​ (In thousands) ​ ​ ​ Assets acquired: ​ ​ ​ Cash and cash equivalents ​ $ 5,482 Receivables ​ 1,914 Prepaid expenses and other assets ​ ​ 575 In-process research and development assets ​ 71,600 Goodwill ​ 11,100 ​ ​ $ 90,671 Liabilities assumed: ​ ​ ​ Accounts Payable and accrued expenses ​ $ 7,886 Acquisition Obligation (Note 7) ​ 7,546 Operating lease liabilities ​ ​ 22 Deferred tax liabilities ​ ​ 9,601 ​ ​ $ 25,055 ​ ​ ​ ​ Net assets acquired ​ $ 65,616 ​ The fair value of IPR&D was capitalized as of the Aceragen Acquisition date and accounted for as indefinite-lived intangible assets until completion or disposition of the assets or abandonment of the associated research and development efforts. Upon successful completion of the development efforts, the useful lives of the IPR&D assets will be determined based on the anticipated period of regulatory exclusivity and will be amortized within operating expenses. Until that time, the IPR&D assets will be subject to impairment testing and will not be amortized. The goodwill recorded related to the acquisition is the excess of the fair value of the consideration transferred by the acquirer over the fair value of the net identifiable assets acquired and liabilities assumed at the date of the Aceragen Acquisition. The goodwill recorded is not deductible for tax purposes. ​ The following summarizes the Company’s indefinite-lived tangible assets acquired in connection with the Aceragen Acquisition and their carrying value as of March 31, 2023 (see Note 4 for further discussion): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Carrying Value ​ ​ Acquisition ​ ​ ​ ​ as of ​ ​ Date ​ ​ ​ ​ March 31, (In thousands) Fair Value Impairment 2023 ACG-701 for Cystic Fibrosis ​ $ 50,700 ​ $ (2,600) ​ $ 48,100 ACG-701 for Melioidosis ​ ​ 14,900 ​ ​ — ​ ​ 14,900 ACG-801 for Farber Disease ​ ​ 6,000 ​ ​ (2,000) ​ ​ 4,000 Total in-process research and development costs (IPR&D) ​ $ 71,600 ​ $ (4,600) ​ $ 67,000 ​ Intangible asset fair values for the three IPR&D programs were determined using the Multi-Period Excess Earnings Method (“MPEEM”) which is a form of the income approach. Under the MPEEM, the fair value of an intangible asset is equal to the present value of the asset's incremental after-tax cash flows (excess earnings) remaining after deducting the market rates of return on the estimated value of contributory assets (contributory charge) over its remaining useful life. To calculate fair value of acquired IPR&D programs under the MPEEM, the Company uses probability-weighted cash flows discounted at a rate considered appropriate given the significant inherent risks associated with drug development by development-stage companies. Cash flows were calculated based on estimated projections of revenues and expenses related to each program and then reduced by a contributory charge on requisite assets employed. Contributory assets included debt-free working capital, net fixed assets and assembled workforce. Rates of return on the contributory assets were based on rates used for comparable market participants. Cash flows were assumed to extend through the market exclusivity period estimated to be provided by orphan drug designation. The resultant cash flows were then discounted to present value using a weighted-average cost of equity capital for companies with profiles substantially similar to that of each acquired IPR&D program, which the Company believes represents the rate that market participants would use to value the assets. The Company compensated for the phase of development of each program by probability-adjusting its estimation of the expected future cash flows. The projected cash flows were based on significant assumptions, such as the time and resources needed to complete the development and approval of each IPR&D program, estimates of revenue and operating profit related to the program considering its stage of development, the life of the potential commercialized product and associated risks, including the inherent difficulties and uncertainties in drug development, such as obtaining marketing approval from the FDA and other regulatory agencies, and risks related to the viability of and potential alternative treatments in any future target markets. See Note 4. ​ Pro Forma Financial Information The following pro forma financial information reflects the consolidated results of operations of the Company for the three months ended March 31, 2022 as if the Aceragen Acquisition had taken place on January 1, 2021. The unaudited pro forma financial information is not necessarily indicative of the results of operations as they would have been had the transactions been effected on the assumed date. ​ ​ ​ ​ ​ ​ ​ March 31, (In thousands) 2022 Net revenues ​ $ 5,688 Net loss ​ $ (7,354) ​

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2023
Fair Value Measurements
Fair Value Measurements	Note 4. Fair Value Measurements ​ Assets and Liabilities Measured at Fair Value on a Recurring Basis ​ The Company applies the guidance in ASC 820, Fair Value Measurement ​ The Company uses a fair value hierarchy, which distinguishes between assumptions based on market data (observable inputs) and an entity's own assumptions (unobservable inputs). The guidance requires that fair value measurements be classified and disclosed in one of the following three categories: ● Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; ● Level 2: Quoted prices in markets that are not active or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability ● Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). ​ Determining which category an asset or liability falls within the hierarchy requires significant judgment. The Company evaluates its hierarchy disclosures each reporting period. There were no transfers between Level 1 , 2 and 3 during the three months ended March 31, 2023. ​ The table below presents the assets and liabilities measured and recorded in the condensed consolidated financial statements at fair value on a recurring basis at March 31, 2023 and December 31, 2022 categorized by the level of inputs used in the valuation of each asset and liability. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 500 ​ $ 500 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 1,618 ​ ​ 1,618 ​ ​ — ​ ​ — ​ Total assets ​ $ 2,118 ​ $ 2,118 ​ $ — ​ $ — ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Series X Preferred Stock liability ​ $ 34,800 ​ $ — ​ $ — ​ $ 34,800 ​ Total liabilities ​ $ 34,800 ​ $ — ​ $ — ​ $ 34,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 3,342 ​ $ 3,342 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 8,702 ​ ​ 8,702 ​ ​ — ​ ​ — ​ Total assets ​ $ 12,044 ​ $ 12,044 ​ $ — ​ $ — ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Warrant liability ​ $ 2,819 ​ $ — ​ $ — ​ $ 2,819 ​ Series X Preferred Stock liability ​ ​ 34,300 ​ ​ — ​ ​ — ​ ​ 34,300 ​ Total liabilities ​ $ 37,119 ​ $ — ​ $ — ​ $ 37,119 ​ ​ The Level 1 assets consist of money market funds, which are actively traded daily. ​ Changes in Level 3 Liabilities Measured at Fair Value on a Recurring Basis ​ Warrant Liability and Series X Preferred Stock Liability ​ The reconciliation of the Company's warrant and Series X Preferred Stock liability measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Series X ​ ​ Warrant ​ Preferred Stock (In thousands) ​ Liability ​ Liability Balance, December 31, 2022 $ 2,819 ​ $ 34,300 Change in fair value ​ ​ 874 ​ 500 Reclassification to stockholders' equity (1) ​ ​ (3,693) ​ — Balance, March 31, 2023 $ — ​ $ 34,800 (1) During the three months ended March 31, 2023, the Company’s liability-classified warrants, representing warrants exercisable for Series Z Preferred Stock, were reclassified to stockholders’ equity upon conversion of such warrants to warrants exercisable for common stock in January 2023. ​ Assumptions Used in Determining Fair Value of Liability-Classified Series X Preferred Stock ​ The fair value of the Series X Preferred Stock represents the present value of estimated future payments that include royalty payments, as well as potential payments contingent upon the Company being awarded a priority review voucher (“PRV”). The Company utilized an income approach and Monte Carlo simulation method to determine the estimated fair value of the Series X Preferred Stock. The inputs used in the valuation approach are based on many factors such as estimated sales proceeds related to the PRV, the relevant market size, the estimated probability of regulatory success rates, anticipated patent protection, expected pricing, expected treated population, sales by region, estimated royalty payments and discount rate. ​ Assets measured at Fair Value on a Nonrecurring Basis The Company’s non-financial assets, which primarily consist of goodwill and IPR&D assets are not required to be measured at fair value on a recurring basis, and instead are reported at their carrying amount. However, on a periodic basis whenever events or changes in circumstances indicate that their carrying values may not be fully recoverable (and at least annually for goodwill and indefinite-lived intangible assets), non-financial assets are assessed for impairment. If the fair value is determined to be lower than the carrying amount, an impairment charge is recorded to write down the asset to its fair value. As a result of the decrease in the Company’s market capitalization during the quarter ended March 31, 2023, the Company determined that a sufficient indicator existed to trigger the performance of an interim impairment analysis for goodwill and IPR&D assets. The IPR&D asset related to ACG-701 for Cystic Fibrosis with a carrying amount of $50.7 million was written down to a fair value of $48.1 million (Level 3 fair value measurement) and the IPR&D asset related to ACG-801 for Farber Disease with a carrying amount of $6.0 million was written down to a fair value of $4.0 million (Level 3 fair value measurement) during the three months ended March 31, 2023. The fair value associated with the IPR&D asset related to ACG-701 for Melioidosis exceeded its carrying value at March 31, 2023. Goodwill with a carrying value of $11.1 million was written down to a fair value of $4.6 million during the three months ended March 31, 2023. The fair value of the Company’s one reporting unit for interim goodwill impairment testing was determined using a market approach. See Note 3.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2023
Accrued Expenses
Accrued Expenses	Note 5. Accrued Expenses ​ At March 31, 2023 and December 31, 2022, accrued expenses consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ($ in thousands) ​ 2023 2022 Payroll and related costs ​ $ 339 ​ $ 1,886 ​ Clinical and nonclinical trial expenses ​ 1,576 ​ 2,106 ​ Professional and consulting fees ​ 1,041 ​ 1,637 ​ Restructuring and other costs (1) ​ 2,882 ​ 2,327 ​ Acquisition-related costs ​ ​ 1,144 ​ ​ 1,666 ​ Other ​ 216 ​ 289 ​ Total accrued expenses ​ $ 7,198 ​ $ 9,911 ​ ​ ​ (1) Includes $1.3 million of severance due to two former executives payable in stock.

Series X Preferred Stock Liabil

Series X Preferred Stock Liability	3 Months Ended
	Mar. 31, 2023
Series X Preferred Stock Liability
Series X Preferred Stock Liability	Note 6. Series X Preferred Stock Liability ​ In connection with the Aceragen Acquisition, the Company issued five shares of Series X Preferred Stock. The shares of Series X Preferred Stock are non-convertible and non-voting and are entitled to discrete development and commercial milestone payments as well as royalty payments on net product sales of ACG-801 for Farber disease. The royalty rates range between low single digits to low double digits and expire, unless terminated earlier, upon the later of the expiration of the last valid claim in the licensed patent rights in such country covering such product and the expiration of data exclusivity in such country for such product. In addition, the payments due to the holders of the Series X shares are secured by substantially all of the assets related to ACG-801. The Company concluded that the shares of Series X Preferred Stock do not represent a residual interest in the Company and are accounted for as debt. The liabilities associated with the shares of Series X Preferred Stock require the Company to make certain estimates and assumptions, particularly about the achievement of future development and regulatory milestones and future product sales. Such estimates and assumptions are utilized in determining the expected repayment term, accretion of interest expense and classification between current and long-term portions of amounts outstanding. The Company elected to carry the Series X Preferred Stock liability at fair value, and the debt instrument is outside the scope of ASC 480, Distinguishing Liabilities from Equity Debt

Acquisition Obligation

Acquisition Obligation	3 Months Ended
	Mar. 31, 2023
Acquisition Obligation
Acquisition Obligation	Note 7. Acquisition Obligation ​ In connection with the Aceragen Acquisition, the Company assumed an obligation pursuant to the Arrevus Merger Agreement (as defined below), whereby Legacy Aceragen was obligated to make an aggregate future payment of $7.8 million to the Former Stockholders (as defined below), $6.3 million and $1.5 million of which was originally due in October 2022 and January 2023, respectively (the “Acquisition Obligation”). The estimated fair value of the Acquisition Obligation on the Effective Date was $7.5 million. During the fourth quarter of 2022, $1.5 million of the $7.8 million obligation was paid. ​ In connection with the closing of the Aceragen Acquisition, Legacy Aceragen entered into a binding term sheet (the “Term Sheet”) with the representative of certain former stockholders of Arrevus (the “Former Stockholders”), pursuant to which Legacy Aceragen and the Former Stockholders agreed to defer certain payments owed by Legacy Aceragen to the Former Stockholders under that certain Agreement and Plan of Merger, dated October 18, 2021, by and among Legacy Aceragen, Arrevus, and their respective affiliates (the “Arrevus Merger Agreement”), in an aggregate amount of $6.0 million (the “Deferred Payments”) until October 24, 2023. The Deferred Payments bear annual interest at 12% beginning on April 1, 2023. The Company may prepay the Deferred Payments at any time, subject to payment in full in cash of the Deferred Payments, plus accrued interest up until the date of such prepayment. Any prepayment of the Deferred Payments must be made on a pro-rata basis among the holders of the Convertible Notes (as defined below) in proportion to their respective shares of the Deferred Payments; provided that prior to any such prepayment, the holder of each Convertible Note shall be given written notice thereof and the option to convert the principal balance into shares of common stock pursuant to the terms of the Convertible Note. ​ Pursuant to the terms of the Term Sheet, on January 31, 2023, the Company issued 12% convertible unsecured promissory notes (the “Convertible Notes”) in an aggregate amount of approximately $5.9 million to certain Former Stockholders the Company determined to be accredited investors and 12% unsecured promissory notes (the “Promissory Notes”) in an aggregate amount of approximately $0.4 million to certain Former Stockholders the determined to be unaccredited investors (collectively, the Convertible Notes and the Promissory Notes, the “January 2023 Notes”). ​ The January 2023 Notes bear annual interest at 12% beginning April 1, 2023. Under the terms of the Convertible Notes, at the holder’s election, any or all of the outstanding principal and accrued interest may be converted into shares of Company’s common stock using a conversion price determined by the VWAP (as defined in the Convertible Notes) on the applicable trading market for the fifteen consecutive trading days ending prior to the date the holder provides notice of their intent to convert. The terms of the Convertible Notes provide the Former Stockholders with customary registration rights covering the Common Stock issued following any conversion of the Convertible Notes. ​ During the period the Term Sheet was in effect, the Company imputed interest expense using the effective interest method based on the difference between the estimated fair value and the notional value. Upon issuance of the January Notes, the Company recognized the remaining unamortized discount on the Acquisition Obligation, resulting in total non-cash charges for the accretion of discounts on the Acquisition Obligation of $0.2 million, which is included in “Interest income (expense), net” within the accompanying condensed consolidated statements of operations and comprehensive loss.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	3 Months Ended
	Mar. 31, 2023
Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock	Note 8. Redeemable Convertible Preferred Stock ​ Series Z Redeemable Preferred Stock ​ In connection with the Aceragen Acquisition, the Company issued 80,656 shares of Series Z Preferred Stock. The Series Z Preferred Stock did not have voting rights except for voting on specific corporate matters including (i) changes to the rights and preferences of the Series Z Preferred Stock, (ii) issuance of additional Series Z Preferred Stock, and (iii) enter into a fundamental transaction such as a sale of the Company. Certain provisions of the Series Z Preferred Stock are as follows: ● Conversion: Upon obtaining stockholder approval at the Special Meeting, each share of Series Z automatically converted into 58.82 shares of common stock, subject to beneficial ownership limitations. ● Dividends: Series Z Preferred Stock was eligible to participate in any dividends with common stockholders on an as-converted basis ● Liquidation: In the event of the liquidation, dissolution, or winding up of the affairs of the Company (a “Liquidity Event ”), prior to stockholder approval at the Special Meeting, the holders of Series Z Preferred Stock would have been entitled to receive a liquidation preference prior to any payment to the holders of common stock. ● Redemption : In the event the Company would have been unable to obtain an affirmative stockholder vote at the Special Meeting to permit conversion, each holder of Series Z Preferred Stock would have been entitled to elect, at the holder’s option, to have the shares of Series Z Preferred Stock be redeemed by the Company and equal to the estimated fair value of the Series Z Preferred Stock share at the time of redemption. Due to this redemption feature, as of December 31, 2022, the Series Z Preferred Stock was classified within temporary equity on the consolidated balance sheet. On January 12, 2023, at the Special Meeting, the Company’s stockholders approved the issuance of shares of the Company’s common stock upon conversion of the Series Z Preferred Stock in accordance with Nasdaq Listing Rule 5635(a). Following approval, effective January 17, 2023, all 80,656 outstanding shares of Series Z Preferred Stock were automatically converted into 4,744,467 shares (including unvested restricted stock awards which are excluded from stockholders’ equity) of the Company’s common stock pursuant to the terms of the Series Z Preferred Stock. Upon conversion, the carrying value of the Series Z Preferred Stock was reclassified to stockholders’ equity.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2023
Stockholders' Equity
Stockholders' Equity	Note 9. Stockholders’ Equity ​ Common and Preferred Stock Warrants ​ In connection with various financing transactions, the Company has issued warrants to purchase shares of the Company’s common stock and preferred stock. The Company accounts for common and preferred stock warrants as equity instruments or liabilities, depending on the specific terms of the warrant agreement. ​ In connection with the Aceragen Acquisition, the Company issued warrants to Legacy Aceragen warrant holders to purchase shares of its common stock and Series Z Preferred Stock. The Series Z Preferred Stock warrants are liability classified and remeasured at each reporting period until the warrants are exercised, reclassified, expire, or otherwise settled. ​ The following table summarizes outstanding warrants to purchase shares of the Company’s common stock and/or preferred stock as of March 31, 2023 and December 31, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Warrants ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ Weighted-Average ​ ​ ​ Description ​ 2023 ​ 2022 ​ Exercise Price ​ Expiration Date Equity-classified warrants: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ May 2013 warrants 908 ​ 908 ​ ​ $ 1.36 ​ None ​ September 2013 warrants 241 ​ 241 ​ ​ $ 1.36 ​ None ​ February 2014 warrants 128 ​ 128 ​ ​ $ 1.36 ​ None ​ April 2020 Private Placement first closing warrants ​ 178,794 ​ 178,794 ​ ​ $ 38.76 ​ Apr 2023 ​ April 2020 Private Placement second closing warrants ​ 80,801 ​ 80,801 ​ ​ $ 46.07 ​ Dec 2023 ​ July 2020 Private Placement first closing warrants ​ 162,601 ​ 162,601 ​ ​ $ 43.86 ​ Jul 2023 ​ Assumed Legacy Aceragen warrants ​ 915,772 ​ 79,596 ​ ​ $ 7.82 ​ Mar 2031 ​ ​ ​ 1,339,245 ​ 503,069 ​ ​ ​ ​ ​ ​ Liability-classified warrants: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assumed Legacy Aceragen Series Z Warrants (1) ​ — ​ 14,215 ​ ​ $ 460.00 ​ Mar 2031 ​ ​ ​ — ​ 14,215 ​ ​ ​ ​ ​ ​ Total outstanding 1,339,245 ​ 517,284 ​ ​ ​ ​ ​ ​ ​ ​ The table below is a summary of the Company's warrant activity for the three months ended March 31, 2023. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Warrants ​ ​ ​ ​ ​ Common Series Z ​ ​ Weighted-Average ​ ​ Warrants Warrants Total ​ Exercise Price (1) Outstanding at December 31, 2022 503,069 14,215 517,284 ​ $ 17.58 Issued — — — ​ — Exercised — — — ​ — Expired — — — ​ — Conversion ​ 836,176 (14,215) 821,961 ​ ​ 7.82 Outstanding at March 31, 2023 1,339,245 — 1,339,245 ​ $ 17.58 (1) During the three months ended March 31, 2023, the Company’s Series Z Preferred Stock Warrants were converted into warrants to purchase common stock. ​ “At-The-Market" Equity Program ​ In November 2018, the Company entered into an Equity Distribution Agreement (the “ATM Agreement”) with JMP Securities LLC (“JMP”) pursuant to which the Company may issue and sell shares of its common stock through JMP as its agent. During each of the three months ended March 31, 2023 and 2022, the Company sold no shares of common stock pursuant to the ATM Agreement.

Government Contracts Revenue

Government Contracts Revenue	3 Months Ended
	Mar. 31, 2023
Government Contracts Revenue
Government Contracts Revenue	Note 10. Government Contracts Revenue ​ Government contracts revenue for the three months ended March 31, 2023 consists of revenue from contracts with customers (U.S. government agencies) accounted for in accordance with ASC Topic 606, as more fully described in Note 2. ​ As of March 31, 2023, the Company had three in-process contracts with various agencies of the U.S. government with a total aggregate contract value of $46.3 million, of which $18.6 million has been used as of March 31, 2023. Of the $27.7 million total contractual value remaining as of March 31, 2023, $27.6 million is related to a contract awarded by Defense Threat Reduction Agency (“DTRA”) to develop ACG-701 as a potential medical countermeasure against the pathogen that causes melioidosis, B. Pseudomallei (the “DTRA Award”). The DTRA Award was granted pursuant to an agreement with a consortium management firm (“CMF”) with a contractual term through December 2026. While the contractual arrangement is with a CMF, the Company has determined that DTRA is the customer in the arrangement and the contract contains a single performance obligation (ACG-801 development services) which meet the criteria to be recognized over time. Other government contracts are not currently material. ​ During the three months ended March 31, 2023, the Company recognized government contract revenues of $2.5 million, of which approximately $2.4 million related to the DTRA Award. No such revenues were recognized during the three months ended March 31, 2022. As of March 31, 2023, there were no material amounts of remaining performance obligations that are required to be disclosed.

Clinical Funding, Collaboration

Clinical Funding, Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2023
Clinical Funding, Collaboration and License Agreements
Clinical Funding, Collaboration and License Agreements	Note 11. Clinical Funding, Collaboration and License Agreements ​ Scriptr Collaboration and Option Agreement ​ In February 2021, the Company entered into a collaboration and option agreement (the “Scriptr Agreement”) with Scriptr Global, Inc. (“Scriptr”), pursuant to which (i) the Company and Scriptr conducted a research collaboration utilizing Scriptr Platform Technology to identify, research and develop gene therapy candidates (each, a “Collaboration Candidate”) for the treatment, palliation, diagnosis or prevention of (a) myotonic dystrophy type 1 and (b) Friedreich’s Ataxia on a Research Program-by-Research Program basis, as applicable, and (ii) the Company was granted an exclusive option, in its sole discretion, to make effective the License Agreement (as defined in the Scriptr Agreement) (the “Scriptr License”) for a given Research Program (as defined in the Scriptr Agreement), to make use of Collaboration Candidates and related intellectual property. ​ The Company incurred approximately $0.3 million in research and development expenses under the Scriptr Agreement during the three months ended March 31, 2022. No such costs were incurred during the three months ended March 31, 2023. ​ In June 2023, the Company and Scriptr mutually agreed to terminate the Scriptr Agreement and all rights and licenses granted pursuant to the Scriptr Agreement, including the option to make effective the License Agreement (as defined in the Scriptr Agreement), were terminated.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2023
Stock-Based Compensation
Stock-Based Compensation	Note 12. Stock-Based Compensation ​ Equity Incentive and Employee Stock Purchase Plans ​ As of March 31, 2023, the only equity compensation plans from which the Company may currently issue new awards are the 2022 Equity Plan (defined below) and the 2017 Employee Stock Purchase Plan (as amended to date, the “2017 ESPP”). ​ 2022 Stock Incentive Plan ​ On January 12, 2023, at the Special Meeting, the Company’s stockholders approved the Idera Pharmaceuticals, Inc. 2022 Stock Incentive Plan (the “2022 Equity Plan”). The 2022 Equity Plan provides for the issuance of incentive stock options, non-qualified stock options, stock awards, stock units, stock appreciation rights, and other stock-based awards. The 2022 Equity Plan was adopted principally to serve as a successor plan to the Idera Pharmaceuticals, Inc. 2013 Stock Incentive Plan (the “2013 Plan”) and to increase the number of shares of the Company’s common stock reserved for equity-based awards by an amount equal to the sum of: (i) 1,388,235 shares of Company common stock, plus (ii) 194,456 shares of Company common stock, which is the number of shares of Company common stock reserved for issuance under the 2013 Plan that remained available for grant under the 2013 Plan as of the effective date of the 2022 Equity Plan. In addition, shares of the Company’s common stock underlying any outstanding award granted under the 2013 Plan that, following the 2022 Equity Plan effective date, expire, or are terminated, surrendered, or forfeited for any reason without issuance of such shares shall be available for new grants under the 2022 Equity Plan. ​ As of March 31, 2023, options to purchase a total of 295,000 shares of common stock were outstanding under the 2022 Equity Plan and 1,319,206 remained available for issuance under the 2022 Equity Plan. ​ 2021 Legacy Aceragen Plan ​ In accordance with the Merger Agreement, the Company assumed and became the sponsor of the Legacy Aceragen’s 2021 Stock Incentive Plan, as amended (the “Legacy Aceragen Plan”). Under the Merger Agreement, each Legacy Aceragen option that was outstanding and unexercised immediately prior to the effective time of the Aceragen Acquisition was assumed and converted into and became an option to purchase (i) shares of the Company’s common stock (the “Legacy Aceragen Common Options”) and (ii) shares of the Company’s Series Z Preferred Stock (the “Legacy Aceragen Preferred Options”), each on the same terms and conditions as applied to such options immediately prior to the Aceragen Acquisition as adjusted by the exchange ratio pursuant to the Merger Agreement. No additional awards were permitted to be issued from the Legacy Aceragen Plan as of the effective time of the Aceragen Acquisition. Following stockholder approval of the Conversion Proposal, and pursuant to the terms of the Merger Agreement, in January 2023, each Legacy Aceragen Preferred Option became exercisable solely for shares of the Company’s common stock. ​ As of March 31, 2023, options to purchase a total of 1,068,004 shares of common stock were outstanding under the Legacy Aceragen Plan. ​ Other Awards and Inducement Grants ​ As of March 31, 2023, options to purchase a total of 271,025 and 4,908 shares of common stock were outstanding under the 2013 Plan and the Idera Pharmaceuticals, Inc. 2008 Stock Incentive Plan (the “2008 Plan”), respectively, and 26,447 unvested restricted stock units were outstanding under the 2013 Plan. In addition, as of March 31, 2023, non-statutory stock options to purchase an aggregate of 19,116 shares of common stock were outstanding that were issued outside of approved equity plans to certain employees in 2015 and 2014 pursuant to the Nasdaq inducement grant exception as a material component of new hires’ employment compensation. ​ 2017 Employee Stock Purchase Plan ​ The 2017 ESPP is intended to qualify as an “employee stock purchase plan” as defined in Section 423 of the Internal Revenue Code of 1986, as amended, and is intended to encourage our employees to become stockholders of ours, to stimulate increased interest in our affairs and success, to afford employees the opportunity to share in our earnings and growth and to promote systematic savings by them. The total number of shares of common stock authorized for issuance under the 2017 ESPP is 59,558 shares of common stock, subject to adjustment as described in the 2017 ESPP. As of March 31, 2023, 39,048 shares remained available for issuance under the 2017 ESPP, however, future offering periods have been suspended until further notice. ​ Accounting for Stock-based Compensation ​ The Company recognizes non-cash compensation expense for stock-based awards under the Company’s equity incentive plans and employee stock purchases under the 2017 ESPP as follows: ​ ● Stock Options : Compensation cost is recognized over an award’s requisite service period, or vesting period, using the straight-line attribution method, based on the grant date fair value determined using the Black-Scholes option-pricing model. ● RSUs : Compensation cost for time-based RSUs, which vest over time based only on continued service, is recognized on a straight-line basis over the requisite service period based on the fair value of the Company’s common stock on the date of grant. Compensation cost for awards that are subject to market considerations is recognized on a straight-line basis over the implied requisite service period, based on the grant date fair value estimated using a Monte Carlo simulation. Compensation cost for awards that are subject to performance conditions is recognized over the period of time commencing when the performance condition is deemed probable of achievement based on the fair value of the Company’s common stock on the date of grant. ● Employee Stock Purchases : Compensation cost is recognized over each plan period based on the fair value of the look-back provision, calculated using the Black-Scholes option-pricing model, considering the 15% discount on shares purchased. Total stock-based compensation expense attributable to stock-based awards made to employees and directors and employee stock purchases included in operating expenses in the Company's condensed statements of operations for the three months ended March 31, 2023 and 2022 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, (in thousands) ​ ​ 2023 2022 Stock-based compensation: ​ ​ ​ ​ ​ ​ Research and development ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ ​ $ — $ 6 Equity Incentive Plans ​ ​ ​ 500 ​ 89 ​ ​ ​ $ 500 $ 95 General and administrative ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ ​ $ — $ 2 Equity Incentive Plans ​ ​ ​ 731 ​ 448 ​ ​ ​ $ 731 $ 450 Total stock-based compensation expense ​ ​ $ 1,231 $ 545 ​ During the three months ended March 31, 2023 and 2022, the weighted average fair market value of stock options granted was $3.49 and $7.14, respectively. ​ The following weighted average assumptions apply to the options to purchase 321,900 and 11,658 shares of common stock granted to employees during the three months ended March 31, 2023 and 2022, respectively: ​ ​ ​ ​ ​ ​ ​ ​ 2023 ​ 2022 Average risk-free interest rate ​ 3.9% ​ ​ 1.3% Expected dividend yield ​ — ​ ​ — Expected lives (years) ​ 3.1 ​ ​ 3.8 Expected volatility ​ 106% ​ ​ 105% Weighted average exercise price (per share) $ 5.21 ​ $ 10.20 ​ All options granted during the three months ended March 31, 2023 and 2022 were granted at exercise prices equal to the fair market value of the Company’s common stock on the date of grant. ​ Stock Option Activity ​ The following table summarizes stock option activity for the three months ended March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Stock Options ($ in thousands, except per share data) ​ Number of Options ​ Weighted-Average Exercise Price ​ Weighted-Average Remaining Contractual Life (in years) ​ Aggregate Intrinsic Value Outstanding at December 31, 2022 406,174 ​ $ 83.00 ​ 6.1 ​ $ 102 Granted 321,900 ​ ​ 5.21 ​ ​ ​ ​ ​ Conversion of preferred stock options to common stock options ​ 994,399 ​ ​ 6.91 ​ ​ ​ ​ ​ Exercised (3,458) ​ ​ 2.21 ​ ​ ​ ​ ​ Forfeited (43,565) ​ ​ 7.94 ​ ​ ​ ​ ​ Expired (17,397) ​ ​ 2.21 ​ ​ ​ ​ ​ Outstanding at March 31, 2023 (1) 1,658,053 ​ $ 25.26 ​ 8.2 ​ $ 20 Exercisable at March 31, 2023 593,192 ​ $ 57.65 ​ 6.5 ​ $ 10 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Preferred Stock Options ($ in thousands, except per share data) ​ Number of Options ​ Weighted-Average Exercise Price ​ Weighted-Average Remaining Contractual Life (in years) ​ ​ Aggregate Intrinsic Value Outstanding at December 31, 2022 17,522 ​ $ 397.02 ​ 9.1 ​ $ 1,073 Exercised ​ (617) ​ ​ 130.00 ​ ​ ​ ​ ​ Conversion of preferred stock options to common stock options ​ (16,905) ​ ​ 406.76 ​ ​ ​ ​ ​ Outstanding at March 31, 2023 (1) — ​ $ — ​ — ​ $ — Exercisable at March 31, 2023 — ​ $ — ​ — ​ $ — (1) Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition. ​ As of March 31, 2023, there was $4.2 million of unrecognized compensation cost related to unvested options, which the Company expects to recognize over a weighted average period of 2.9 years. Restricted Stock Unit Activity ​ The following table summarizes restricted stock unit activity for the three months ended March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-based Awards ​ Market/Performance-based Awards ​ ​ Number of Shares ​ Weighted-Average Grant Date Fair Value ​ Number of Shares ​ Weighted-Average Grant Date Fair Value Nonvested shares at December 31, 2022 19,096 ​ $ 10.73 29,814 ​ $ 26.14 Granted — ​ — — ​ — Cancelled (294) ​ ​ — ​ (6,030) ​ ​ — Vested (1,601) ​ — (14,538) ​ — Nonvested shares at March 31, 2023 ​ 17,201 ​ $ 7.54 ​ 9,246 ​ $ 26.14 ​ As of March 31, 2023, remaining unrecognized compensation expense related to the Company’s outstanding RSUs was immaterial. ​ ​ ​ ​ Restricted Stock Activity The following table summarizes restricted stock activity for the three months ended March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ Number of Shares ​ ​ Common Stock ​ Series Z Nonvested shares at December 31, 2022 15,432 ​ 2,756 Granted — ​ — Conversion of preferred stock RSAs to common stock RSAs ​ 75,471 ​ (1,283) Cancelled (7,962) ​ (1,426) Vested (6,386) ​ (47) Nonvested shares at March 31, 2023 76,555 ​ — ​

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2023
Related Party Transactions
Related Party Transactions	Note 13. Related Party Transactions ​ Pillar Investment Entities ​ Youssef El Zein, a member of the Company’s Board until his resignation in October 2017, is a director and controlling stockholder of Pillar Invest Corporation (“Pillar Invest”), which is the general partner of Pillar Pharmaceuticals I, L.P., Pillar Pharmaceuticals II, L.P., Pillar Pharmaceuticals III, L.P., Pillar Pharmaceuticals IV, L.P., Pillar Pharmaceuticals V, L.P., Pillar 6, Pillar 7 and Pillar Partners (collectively, the “Pillar Investment Entities”). As of March 31, 2023, the Pillar Investment Entities beneficially owned 985,204 shares of the Company's common stock. ​ As of March 31, 2023, the Pillar Investment Entities held (i) warrants to purchase up to 178,794 shares of the Company’s common stock at an exercise price of $38.76 per share, (ii) warrants to purchase up to 162,601 shares of the Company’s common stock at an exercise price of $43.86 per share, and (iii) warrants to purchase up to 80,801 shares of the Company’s common stock at an exercise price of $46.07 per share. ​ NovaQuest ​ Ron Wooten, a member of the Company’s Board, is a member of the investment committee of NQ POF V GP, Ltd. ("NovaQuest GP"), which is the general partner of NovaQuest. ​ In connection with the Aceragen Acquisition, NovaQuest was issued five shares of Series X Preferred Stock. In addition, all outstanding warrants to purchase Legacy Aceragen common stock held by NovaQuest immediately prior to the Aceragen Acquisition were assumed by the Company and converted into warrants to purchase shares of the Company’s common stock and Series Z Preferred Stock on terms substantially identical to those in effect prior to the Aceragen Acquisition, except for adjustments to the underlying number of shares and the exercise price based on the Merger Agreement exchange ratio. Following the Conversion Approval, warrants held by NovaQuest to purchase 14,115 shares of Series Z Preferred Stock were automatically converted into warrants to purchase 830,294 shares of the Company’s common stock. ​ As of March 31, 2023, NovaQuest held five shares of Series X Preferred Stock and warrants to purchase 909,326 shares of the Company’s common stock. ​ Board Fees Paid in Stock ​ Pursuant to the Company’s director compensation program, in lieu of director board and committee fees of less than $0.1 million incurred during the three months ended March 31, 2022, the Company issued 2,420 shares of common stock to a director. No shares were issued in lieu of director board and committee fees incurred during the three months ended March 31, 2023. Director board and committee fees are paid in arrears and the number of shares issued was calculated based on the market closing price of the Company’s common stock on the issuance date.

Net Loss per Common Share

Net Loss per Common Share	3 Months Ended
	Mar. 31, 2023
Net Loss per Common Share
Net Loss per Common Share	Note 14. Net Loss per Common Share ​ During periods the Company realizes net income, it uses the two-class method to compute net income per common share and has securities outstanding (redeemable convertible preferred stock) that entitle the holder to participate in dividends and earnings of the Company. In addition, the Company analyzes the potential dilutive effect of outstanding redeemable convertible preferred stock under the "if-converted" method when calculating diluted earnings per share and reports the more dilutive of the approaches (two class or "if-converted"). During each of the three months ended March 31, 2023 and 2022, the two-class method was not applicable as the Company incurred a net loss and holders of the redeemable convertible preferred stock have no obligation to fund losses. ​ The Company also analyzes the potential dilutive effect of stock options, unvested restricted stock and restricted stock units, and warrants under the treasury stock method (as applicable), during periods of income, or during periods in which income is recognized related to changes in fair value of its liability-classified securities. ​ During periods the Company realizes net loss, basic and diluted net loss per common share applicable to common stockholders is calculated by dividing net loss applicable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of common stock equivalents. The Company’s potentially dilutive shares, which include outstanding stock option awards, unvested restricted stock and restricted stock units, warrants and convertible preferred stock, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. ​ For the three months ended March 31, 2023 and 2022, diluted net loss per common share applicable to common stockholders was the same as basic net loss per common share applicable to common stockholders as the effects of the Company’s potential common stock equivalents were antidilutive. ​ Total antidilutive securities excluded from the calculation of diluted net loss per share for the three months ended March 31, 2023 and 2022 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ ​ 2023 ​ ​ 2022 Common stock options ​ ​ 1,658,053 ​ ​ 283,526 Restricted stock units and restricted stock awards ​ ​ 103,002 ​ ​ 32,253 Common stock warrants ​ ​ 1,339,245 ​ ​ 513,658 Convertible preferred stock ​ ​ 14 ​ ​ 14 Total ​ ​ 3,100,314 ​ ​ 829,451 ​

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2023
Subsequent Events.
Subsequent Events	Note 15. Subsequent Events ​ The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the condensed consolidated financial statements to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. In some instances, such subsequent events may require retroactive adjustment to information reported at the balance sheet date. ​ Cost-reduction Plan Implementation and Reduction in Workforce ​ On April 28, 2023, the Board approved a reduction in workforce (the “Reduction”) in which approximately 80% of the Company’s employees were terminated, effective immediately, in an effort to reduce operating costs. This follows the previously disclosed approval by the Board, on April 13, 2023, of certain cost-cutting measures, including the furlough of approximately 46% of the Company’s workforce and the deferral of base salaries in amounts that exceed $200,000, effective as of April 5, 2023. ​ In connection with the Reduction, the Company incurred aggregate restructuring charges in the second quarter of 2023 of approximately $4.6 million related to severance payments and other employee-related costs. The Company may also incur additional costs not currently contemplated due to events that may occur as a result of, or that are associated with, the Reduction. ​ Nasdaq Delisting Notice and Public Shell Inquiry ​ On May 24, 2023, the Company received a notice (the “Notice”) from the Nasdaq Listing Qualifications Department (the “Staff”), stating that because the Company had not yet filed its Quarterly Report on Form 10-Q for the three months ended March 31, 2023, the Company was not in compliance with Nasdaq Listing Rule 5250(c)(1). Nasdaq Listing Rule 5250(c)(1) requires listed companies to timely file all required periodic financial reports with the SEC. ​ Collaboration with Scriptr ​ In June 2023, the Company and Scriptr mutually agreed to terminate the Scriptr Agreement and all rights and licenses granted pursuant to the Scriptr Agreement, including the option to make effective the License Agreement (as defined in the Scriptr Agreement), were terminated. The termination of the Scriptr Agreement is not expected to have a material effect on the Company’s condensed consolidated financial statements. ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation ​ The accompanying unaudited condensed consolidated financial statements included herein have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the SEC. Accordingly, certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three months ended March 31, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s 2022 Form 10-K filed with the SEC. ​
Financial Instruments	Financial Instruments ​ The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 4. The Company is required to disclose the estimated fair values of its financial instruments. As of March 31, 2023 and December 31, 2022, the Company’s financial instruments included cash and cash equivalents, accounts receivable, accounts payable, Acquisition Obligation (defined below), and Series X Preferred Stock and Series Z Preferred Stock Warrant liabilities. The carrying amount of cash and cash equivalents, accounts receivable, and accounts payable approximates fair value due to the short-term maturities of these instruments. The carrying values of the Acquisition Obligation (defined below), Series X Preferred Stock liability and Series Z Preferred Stock Warrants liability are recorded at their estimated fair values. As of March 31, 2023, the Company did not have any other derivatives, hedging instruments or other similar financial instruments.
Concentration of Credit Risk	​ Concentration of Credit Risk ​ Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash, which, at times, may exceed federally insured limits, and cash equivalents consisting of investments in money market funds managed by a variety of financial institutions. The Company's credit risk is managed by investing in only highly rated money market instruments. As a result, no significant additional credit risk is believed by management to be inherent in the Company’s assets and the Company has not experienced any losses in such accounts and believes it is not exposed to any significant risk on such accounts.
Business Combinations	Business Combinations ​ The Company evaluates acquisitions of assets and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs, which would meet the requirements of a business. If determined to be a business combination, the Company accounts for the transaction under the acquisition method of accounting as indicated in ASU 2017-01, Business Combinations (ASC 805) Business Combinations
Cash and Cash Equivalents	Cash and Cash Equivalents ​ The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at March 31, 2023 and December 31, 2022 consisted of cash and money market funds.
Accounts Receivable	Accounts Receivable ​ The U.S. Government accounted for all of the Company’s accounts receivable as of March 31, 2023. Accordingly, the Company does not expect any credit losses with respect to its accounts receivable and no credit losses have been incurred to date. Included in accounts receivable at March 31, 2023 is $0.3 million of unbilled receivables which relates to revenue recognized for work that has been performed but the invoicing has not yet occurred as of the reporting date.
Indefinite-Lived Intangible Assets	Indefinite-Lived Intangible Assets ​ Indefinite-lived intangible assets consist of In-Process Research and Development (“IPR&D”). The fair values of IPR&D project assets acquired in business combinations are capitalized. The Company generally utilizes the Multi-Period Excess Earning Method to determine the estimated fair value of the IPR&D assets acquired in a business combination. The projections used in this valuation approach are based on many factors, such as relevant market size, the estimated probability of regulatory success rates, anticipated patent protection, expected pricing, expected treated population, and estimated payments (e.g., royalty). The estimated future net cash flows are then discounted to the present value using an appropriate discount rate. These assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are amortized over the remaining useful life or written off, as appropriate. ​ Intangible assets with indefinite lives, including IPR&D, are tested for impairment if impairment indicators arise and, at a minimum, annually. However, an entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that an indefinite-lived intangible asset’s fair value is less than its carrying amount. Otherwise, no further impairment testing is required. The indefinite-lived intangible asset impairment test consists of a one-step analysis that compares the fair value of the intangible asset with its carrying amount. If the carrying amount of an intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. The Company considers many factors in evaluating whether the value of our intangible assets with indefinite lives may not be recoverable, including, but not limited to, expected growth rates, the cost of equity and debt capital, general economic conditions, our outlook and market performance of the Company’s industry and recent and forecasted financial performance. ​ The Company evaluates indefinite-lived intangible assets for impairment at least annually on October 1 and whenever facts and circumstances indicate that their carrying amounts may not be recoverable. During the three months ended March 31, 2023, management identified an indicator of impairment related to the decrease in the Company’s market capitalization. As a result, the Company performed an interim impairment test that resulted in the recognition of an impairment loss of $4.6 million related to IPR&D (see Note 3 and 4 for further discussion).
Goodwill	Goodwill ​ Goodwill represents the amount of consideration paid in excess of the fair value of net assets acquired as a result of the Company’s business acquisitions accounted for using the acquisition method of accounting. The intangible assets acquired represented the fair value of IPR&D which has been recorded on the accompanying condensed consolidated balance sheet as indefinite-lived intangible assets. A deferred tax liability was recorded for the difference between the fair value of the acquired IPR&D and its tax basis which was recognized as goodwill in applying the purchase method of accounting. Goodwill is not amortized and is subject to impairment testing at a reporting unit level on an annual basis or when a triggering event occurs that may indicate the carrying value of the goodwill is impaired. An entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that the fair value of the reporting unit is less than its carrying amount. ​ The Company evaluates goodwill for impairment at least annually on October 1 and whenever facts and circumstances indicate that the carrying amount of the reporting unit is greater than its fair value. During the three months ended March 31, 2023, management identified an indicator of impairment related to the decrease in the Company’s market capitalization. As a result, the Company performed an interim impairment test that resulted in the recognition of an impairment loss of $6.5 million related to goodwill (see Note 3 and 4 for further discussion).
Operating Lease Right-of-use Asset and Lease Liability	Operating Lease Right-of-use Asset and Lease Liability ​ The Company accounts for leases under ASC 842, Leases. Operating leases are included in “Operating lease right-of-use assets” within the Company’s condensed consolidated balance sheets and represent the Company’s right to use an underlying asset for the lease term. The Company’s related obligation to make lease payments are included in “Operating lease liability” and “Operating lease liability, net of current portion” within the Company’s condensed consolidated balance sheets. Operating lease right-of-use (“ROU”) assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The ROU assets are tested for impairment according to ASC 360, Property, Plant, and Equipmen ​ As of March 31, 2023 and December 31, 2022, the Company’s operating lease ROU assets and corresponding short-term and long-term lease liabilities primarily relate to its existing Exton, PA facility operating lease, which expires on May 31, 2025. In connection with the Aceragen Acquisition, the Company acquired an operating lease for an office in Basel, Switzerland, which expired on March 31, 2023.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets ​ In accordance with ASC 360-10-35, Impairment or Disposal of Long-Lived Assets among other things, depreciation and obsolescence. Fair value, utilizing the market approach, benchmarks the fair value against the carrying amount.
Other Current Liability	Other Current Liability ​ In January 2023, the Company entered into a short-term financing arrangement with a third-party vendor to finance insurance premiums. The aggregate amount financed under this agreement was $0.9 million. As of March 31, 2023, the balance of $0.7 million, which is included in “Other current liability’ in the Company’s condensed consolidated balance sheets, is scheduled to be paid in monthly installments through August 2023. Total interest to be incurred under the financing arrangement is not material.
Warrant Liability	Warrant Liability ​ The Company accounts for stock warrants as either equity instruments, liabilities or derivative liabilities in accordance with ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging ​ In connection with the Aceragen Acquisition, a portion of the consideration paid to Legacy Aceragen warrant holders was in the form of warrants to purchase shares of Series Z Preferred Stock (“Series Z Warrants”). Such warrants were classified as liabilities upon issuance and as of December 31, 2022 because the underlying Series Z Preferred Stock is contingently redeemable. During the three months ended March 31, 2023, all of the Company’s liability-classified Series Z Warrants were converted into warrants to purchase common stock and, accordingly, the Series Z Warrant liability was reclassified to stockholders’ equity.
Redeemable Preferred Stock	Redeemable Preferred Stock ​ The Company applies ASC 480 when determining the classification and measurement of its preferred stock. Preferred shares subject to mandatory redemption are classified as liability instruments and are measured at fair value. Conditionally redeemable preferred shares (including preferred shares that feature redemption rights that are either within the control of the holder or subject to redemption upon the occurrence of uncertain events not solely within the Company’s control) are classified as temporary equity. At all other times, preferred shares are classified as stockholders’ equity.
Series X Preferred Stock Liability	Series X Preferred Stock Liability ​ In conjunction with the Aceragen Acquisition, the Company evaluated the newly issued Series X Preferred Stock and determined its revised terms represents a sale of future revenues and is classified as a liability under ASC 470, Debt
Revenue Recognition	​ Revenue Recognition ​ The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers ​ Government Contract Revenue ​ Revenues from reimbursable contracts are recognized as costs are incurred, generally based on allowable direct costs incurred during the period, plus allocable overheads together with any recognizable earned fee. The Company uses this output method to measure progress as the customer has access to the development research under these projects and benefits incrementally as research and development activities occur. ​ See Note 10, “Government Contracts Revenue,” of the notes to these condensed consolidated financial statements for discussion of the Company’s cost reimbursement contracts. ​ Customer Concentration Risk ​ The U.S. Government accounted for all of the Company’s revenues for the three months ended March 31, 2023.
Goodwill and Intangible Assets Impairment	Goodwill and Intangible Assets Impairment ​ The Company incurred total impairment losses of $11.1 million during the three months ended March 31, 2023, consisting of impairment losses of its IPR&D and goodwill totaling $4.6 million and $6.5 million, respectively, as more fully described above.
Restructuring and Other Costs	Restructuring and Other Costs ​ In connection with the Aceragen Acquisition, the Company determined to restructure its operations and reduce its workforce which resulted in seven positions being eliminated by December 31, 2022, representing approximately 54% of the Company’s pre-Aceragen Acquisition employees. As a result of the above restructuring initiatives, the Company incurred total restructuring-related charges of $5.0 million to date, including $1.3 million during the three months ended March 31, 2023 related to severance payments to two former executives which were contingent on obtaining shareholder approval at the Special Meeting, which occurred in January 2023. Such amounts are payable in stock and are included in accrued expenses as of March 31, 2023. ​ As of March 31, 2023, of the $5.0 million total restructuring-related charges incurred, $3.4 million remain unpaid and are included in accrued expenses in the accompanying condensed consolidated balance sheet. See Note 5.
Acquisition-Related Costs	Acquisition-Related Costs ​ Acquisition-related costs include direct expenses incurred in connection with the Aceragen Acquisition, as well as integration-related professional fees, employee retention-related benefits, and other incremental costs directly associated to the Aceragen Acquisition. For the three months ended March 31, 2023 acquisition-related costs totaled $0.8 million.
Income Taxes	Income Taxes ​ In accordance with ASC 270, Interim Reporting Income Taxes acquired in connection with the Aceragen Acquisition the recognition of an impairment loss on such IPR&D assets (see Note 4) and reevaluation of the realizability of the Company’s deferred tax assets. No such income tax benefit (or expense) was recorded during the three months ended March 31, 2022.
Net Loss per Common Share Applicable to Common Stockholders	Net Loss per Common Share Applicable to Common Stockholders ​ The Company uses the two-class method to compute net income per common share during periods the Company realizes net income and has securities outstanding (e.g., redeemable convertible preferred stock) that entitle the holder to participate in dividends and earnings of the Company. In addition, the Company analyzes the potential dilutive effect of outstanding redeemable convertible preferred stock under the "if-converted" method when calculating diluted earnings per share and reports the more dilutive of the approaches (two class or "if-converted"). The two-class method is not applicable during periods with a net loss, as the holders of the redeemable convertible preferred stock have no obligation to fund losses. The Company also analyzes the potential dilutive effect of outstanding stock options, unvested restricted stock and restricted stock units, and warrants under the treasury stock method (as applicable), during periods of income, or during periods in which income is recognized related to changes in fair value of its liability-classified securities.
New Accounting Pronouncements	New Accounting Pronouncements ​ From time to time, new accounting pronouncements are issued by the FASB and rules are issued by the SEC that the Company has or will adopt as of a specified date. Unless otherwise noted, management does not believe that any other recently issued accounting pronouncements issued by the FASB or guidance issued by the SEC had, or is expected to have, a material impact on the Company’s present or future consolidated financial statements.

Business Acquisition (Tables)

Business Acquisition (Tables)	3 Months Ended
	Mar. 31, 2023
Business Acquisition
Schedule of purchase price consideration	​ ​ ​ ​ ​ (In thousands) ​ Common stock issued to Aceragen stockholders ​ $ 2,809 Series Z issued to Aceragen stockholders (Note 8) ​ 25,085 Series X liability in connection with Aceragen Acquisition (Note 6) ​ ​ 31,900 Stock options, restricted stock and warrants allocated to consideration paid ​ 5,822 Total Consideration paid ​ $ 65,616
Summary of preliminary allocation of the purchase price to the assets acquired and liabilities assumed	​ ​ ​ ​ ​ (In thousands) ​ ​ ​ Assets acquired: ​ ​ ​ Cash and cash equivalents ​ $ 5,482 Receivables ​ 1,914 Prepaid expenses and other assets ​ ​ 575 In-process research and development assets ​ 71,600 Goodwill ​ 11,100 ​ ​ $ 90,671 Liabilities assumed: ​ ​ ​ Accounts Payable and accrued expenses ​ $ 7,886 Acquisition Obligation (Note 7) ​ 7,546 Operating lease liabilities ​ ​ 22 Deferred tax liabilities ​ ​ 9,601 ​ ​ $ 25,055 ​ ​ ​ ​ Net assets acquired ​ $ 65,616
Schedule of intangible assets acquired in connection with the Aceragen Acquisition	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Carrying Value ​ ​ Acquisition ​ ​ ​ ​ as of ​ ​ Date ​ ​ ​ ​ March 31, (In thousands) Fair Value Impairment 2023 ACG-701 for Cystic Fibrosis ​ $ 50,700 ​ $ (2,600) ​ $ 48,100 ACG-701 for Melioidosis ​ ​ 14,900 ​ ​ — ​ ​ 14,900 ACG-801 for Farber Disease ​ ​ 6,000 ​ ​ (2,000) ​ ​ 4,000 Total in-process research and development costs (IPR&D) ​ $ 71,600 ​ $ (4,600) ​ $ 67,000
Schedule of pro forma financial information	​ ​ ​ ​ ​ ​ ​ March 31, (In thousands) 2022 Net revenues ​ $ 5,688 Net loss ​ $ (7,354)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Measurements
Schedule of assets and liabilities measured and recorded in financial statements at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 500 ​ $ 500 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 1,618 ​ ​ 1,618 ​ ​ — ​ ​ — ​ Total assets ​ $ 2,118 ​ $ 2,118 ​ $ — ​ $ — ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Series X Preferred Stock liability ​ $ 34,800 ​ $ — ​ $ — ​ $ 34,800 ​ Total liabilities ​ $ 34,800 ​ $ — ​ $ — ​ $ 34,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ (In thousands) ​ Total ​ Level 1 ​ Level 2 ​ Level 3 ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 3,342 ​ $ 3,342 ​ $ — ​ $ — ​ Cash equivalents – money market funds ​ ​ 8,702 ​ ​ 8,702 ​ ​ — ​ ​ — ​ Total assets ​ $ 12,044 ​ $ 12,044 ​ $ — ​ $ — ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Warrant liability ​ $ 2,819 ​ $ — ​ $ — ​ $ 2,819 ​ Series X Preferred Stock liability ​ ​ 34,300 ​ ​ — ​ ​ — ​ ​ 34,300 ​ Total liabilities ​ $ 37,119 ​ $ — ​ $ — ​ $ 37,119 ​
Schedule of reconciliation measured at fair value on a recurring basis using unobservable inputs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Series X ​ ​ Warrant ​ Preferred Stock (In thousands) ​ Liability ​ Liability Balance, December 31, 2022 $ 2,819 ​ $ 34,300 Change in fair value ​ ​ 874 ​ 500 Reclassification to stockholders' equity (1) ​ ​ (3,693) ​ — Balance, March 31, 2023 $ — ​ $ 34,800 (1) During the three months ended March 31, 2023, the Company’s liability-classified warrants, representing warrants exercisable for Series Z Preferred Stock, were reclassified to stockholders’ equity upon conversion of such warrants to warrants exercisable for common stock in January 2023.

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2023
Accrued Expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ($ in thousands) ​ 2023 2022 Payroll and related costs ​ $ 339 ​ $ 1,886 ​ Clinical and nonclinical trial expenses ​ 1,576 ​ 2,106 ​ Professional and consulting fees ​ 1,041 ​ 1,637 ​ Restructuring and other costs (1) ​ 2,882 ​ 2,327 ​ Acquisition-related costs ​ ​ 1,144 ​ ​ 1,666 ​ Other ​ 216 ​ 289 ​ Total accrued expenses ​ $ 7,198 ​ $ 9,911 ​ ​ ​ (1) Includes $1.3 million of severance due to two former executives payable in stock.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2023
Stockholders' Equity
Schedule of warrants outstanding and exercisable for purchase of common stock	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Warrants ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ Weighted-Average ​ ​ ​ Description ​ 2023 ​ 2022 ​ Exercise Price ​ Expiration Date Equity-classified warrants: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ May 2013 warrants 908 ​ 908 ​ ​ $ 1.36 ​ None ​ September 2013 warrants 241 ​ 241 ​ ​ $ 1.36 ​ None ​ February 2014 warrants 128 ​ 128 ​ ​ $ 1.36 ​ None ​ April 2020 Private Placement first closing warrants ​ 178,794 ​ 178,794 ​ ​ $ 38.76 ​ Apr 2023 ​ April 2020 Private Placement second closing warrants ​ 80,801 ​ 80,801 ​ ​ $ 46.07 ​ Dec 2023 ​ July 2020 Private Placement first closing warrants ​ 162,601 ​ 162,601 ​ ​ $ 43.86 ​ Jul 2023 ​ Assumed Legacy Aceragen warrants ​ 915,772 ​ 79,596 ​ ​ $ 7.82 ​ Mar 2031 ​ ​ ​ 1,339,245 ​ 503,069 ​ ​ ​ ​ ​ ​ Liability-classified warrants: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assumed Legacy Aceragen Series Z Warrants (1) ​ — ​ 14,215 ​ ​ $ 460.00 ​ Mar 2031 ​ ​ ​ — ​ 14,215 ​ ​ ​ ​ ​ ​ Total outstanding 1,339,245 ​ 517,284 ​ ​ ​ ​ ​ ​
Summary of warrant activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Warrants ​ ​ ​ ​ ​ Common Series Z ​ ​ Weighted-Average ​ ​ Warrants Warrants Total ​ Exercise Price (1) Outstanding at December 31, 2022 503,069 14,215 517,284 ​ $ 17.58 Issued — — — ​ — Exercised — — — ​ — Expired — — — ​ — Conversion ​ 836,176 (14,215) 821,961 ​ ​ 7.82 Outstanding at March 31, 2023 1,339,245 — 1,339,245 ​ $ 17.58

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Stock-Based Compensation
Schedule of stock-based compensation expense attributable to share-based payments made to employees and directors and included in operating expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, (in thousands) ​ ​ 2023 2022 Stock-based compensation: ​ ​ ​ ​ ​ ​ Research and development ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ ​ $ — $ 6 Equity Incentive Plans ​ ​ ​ 500 ​ 89 ​ ​ ​ $ 500 $ 95 General and administrative ​ ​ ​ ​ ​ ​ ​ Employee Stock Purchase Plan ​ ​ $ — $ 2 Equity Incentive Plans ​ ​ ​ 731 ​ 448 ​ ​ ​ $ 731 $ 450 Total stock-based compensation expense ​ ​ $ 1,231 $ 545
Schedule of weighted average assumptions applied to options	​ ​ ​ ​ ​ ​ ​ ​ 2023 ​ 2022 Average risk-free interest rate ​ 3.9% ​ ​ 1.3% Expected dividend yield ​ — ​ ​ — Expected lives (years) ​ 3.1 ​ ​ 3.8 Expected volatility ​ 106% ​ ​ 105% Weighted average exercise price (per share) $ 5.21 ​ $ 10.20
Schedule of information related to outstanding and exercisable options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Stock Options ($ in thousands, except per share data) ​ Number of Options ​ Weighted-Average Exercise Price ​ Weighted-Average Remaining Contractual Life (in years) ​ Aggregate Intrinsic Value Outstanding at December 31, 2022 406,174 ​ $ 83.00 ​ 6.1 ​ $ 102 Granted 321,900 ​ ​ 5.21 ​ ​ ​ ​ ​ Conversion of preferred stock options to common stock options ​ 994,399 ​ ​ 6.91 ​ ​ ​ ​ ​ Exercised (3,458) ​ ​ 2.21 ​ ​ ​ ​ ​ Forfeited (43,565) ​ ​ 7.94 ​ ​ ​ ​ ​ Expired (17,397) ​ ​ 2.21 ​ ​ ​ ​ ​ Outstanding at March 31, 2023 (1) 1,658,053 ​ $ 25.26 ​ 8.2 ​ $ 20 Exercisable at March 31, 2023 593,192 ​ $ 57.65 ​ 6.5 ​ $ 10 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Preferred Stock Options ($ in thousands, except per share data) ​ Number of Options ​ Weighted-Average Exercise Price ​ Weighted-Average Remaining Contractual Life (in years) ​ ​ Aggregate Intrinsic Value Outstanding at December 31, 2022 17,522 ​ $ 397.02 ​ 9.1 ​ $ 1,073 Exercised ​ (617) ​ ​ 130.00 ​ ​ ​ ​ ​ Conversion of preferred stock options to common stock options ​ (16,905) ​ ​ 406.76 ​ ​ ​ ​ ​ Outstanding at March 31, 2023 (1) — ​ $ — ​ — ​ $ — Exercisable at March 31, 2023 — ​ $ — ​ — ​ $ — (1) Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition.
Schedule of information related to restricted stock activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Time-based Awards ​ Market/Performance-based Awards ​ ​ Number of Shares ​ Weighted-Average Grant Date Fair Value ​ Number of Shares ​ Weighted-Average Grant Date Fair Value Nonvested shares at December 31, 2022 19,096 ​ $ 10.73 29,814 ​ $ 26.14 Granted — ​ — — ​ — Cancelled (294) ​ ​ — ​ (6,030) ​ ​ — Vested (1,601) ​ — (14,538) ​ — Nonvested shares at March 31, 2023 ​ 17,201 ​ $ 7.54 ​ 9,246 ​ $ 26.14
Schedule of summary of restricted stock activity	​ ​ ​ ​ ​ ​ ​ ​ Number of Shares ​ ​ Common Stock ​ Series Z Nonvested shares at December 31, 2022 15,432 ​ 2,756 Granted — ​ — Conversion of preferred stock RSAs to common stock RSAs ​ 75,471 ​ (1,283) Cancelled (7,962) ​ (1,426) Vested (6,386) ​ (47) Nonvested shares at March 31, 2023 76,555 ​ —

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	3 Months Ended
	Mar. 31, 2023
Net Loss per Common Share
Schedule of potentially dilutive securities excluded from diluted net income (loss) per common share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ ​ ​ 2023 ​ ​ 2022 Common stock options ​ ​ 1,658,053 ​ ​ 283,526 Restricted stock units and restricted stock awards ​ ​ 103,002 ​ ​ 32,253 Common stock warrants ​ ​ 1,339,245 ​ ​ 513,658 Convertible preferred stock ​ ​ 14 ​ ​ 14 Total ​ ​ 3,100,314 ​ ​ 829,451

Business and Organization (Deta

Business and Organization (Details) $ in Thousands	Apr. 28, 2023	Jan. 17, 2023	Sep. 27, 2022 USD ($)	Oct. 25, 2021 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Accumulated deficit					$ 780,688	$ 758,821
Cash, cash equivalents and investments					$ 2,100
Percentage of positions eliminated	80%
Reverse stock split conversion ratio		0.059
NovaQuest
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Maximum amount agreed to be paid by related party				$ 35,000
Proceeds from sale of common stock and warrants				15,000
Capital contributions committed				$ 20,000
Proceeds from related party			$ 20,000
Interest rate				12%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Thousands		3 Months Ended		6 Months Ended	12 Months Ended
	Apr. 28, 2023	Mar. 31, 2023 USD ($) person	Mar. 31, 2022 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) position	Jan. 31, 2023 USD ($)
Summary of Significant Accounting Policies
Unbilled accounts receivable		$ 300		$ 300
Short term borrowings						$ 900
Other current liability		733		733
Impairment losses		11,100
Impairment of intangible assets		4,600
Impairment of goodwill		6,500
Percentage of positions eliminated	80%
Restructuring costs		1,300		5,000
Restructuring reserve		3,400		3,400
Business combination acquisition related costs		800
Uncertain tax positions		0		0	$ 0
Tax expense (benefit)		(273)	$ 0
Employee Severance and Benefits
Summary of Significant Accounting Policies
Number of positions eliminated | position					7
Percentage of positions eliminated					54%
Restructuring costs		$ 1,300		$ 5,000
Number of former executives | person		2
IPR&D
Summary of Significant Accounting Policies
Impairment of intangible assets		$ 4,600

Business Acquisition - Addition

Business Acquisition - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
	Sep. 28, 2022	Mar. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Preferred stock, par value		$ 0.01	$ 0.01	$ 0.01
Transaction costs		$ 800
Restructuring costs		1,300	$ 5,000
Series X preferred stock
Business Acquisition [Line Items]
Preferred stock, par value	$ 0.01
Aceragen
Business Acquisition [Line Items]
Fair value of total consideration		$ 65,616
Aceragen | Merger Agreement
Business Acquisition [Line Items]
Outstanding security interests percentage	100%
Number of share acquisitions	451,608
Aceragen | Series Z convertible preferred stock | Merger Agreement
Business Acquisition [Line Items]
Shares issued during the acquisitions	80,656
Aceragen | Series X preferred stock | Merger Agreement
Business Acquisition [Line Items]
Number of share acquisitions	5

Business Acquisition - Purchase

Business Acquisition - Purchase price consideration (Details) - Aceragen $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Business Acquisition
Total Consideration paid	$ 65,616
Stock options, restricted stock and warrants
Business Acquisition
Stock issued	5,822
Series Z convertible preferred stock | Stock options, restricted stock and warrants
Business Acquisition
Stock issued	25,085
Series X preferred stock | Stock options, restricted stock and warrants
Business Acquisition
Stock issued	31,900
Common Stock | Stock options, restricted stock and warrants
Business Acquisition
Stock issued	$ 2,809

Business Acquisition - Allocati

Business Acquisition - Allocation of the purchase price to the assets acquired and liabilities assumed (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Assets acquired:
Goodwill	$ 4,629	$ 11,100
Aceragen
Assets acquired:
Cash and cash equivalents	5,482
Receivables	1,914
Prepaid expenses and other assets	575
In-process research and development assets	71,600
Goodwill	11,100
Total assets acquired	90,671
Liabilities assumed:
Accounts Payable and accrued expenses	7,886
Acquisition Obligation (Note 7)	7,546
Operating lease liabilities	22
Deferred tax liabilities	9,601
Total liabilities assumed	25,055
Net assets acquired	$ 65,616

Business Acquisition - Summary

Business Acquisition - Summary of intangible assets acquired (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Business Acquisition
Impairment of intangible assets	$ 4,600
Aceragen
Business Acquisition
Acquisition Date Fair Value	71,600
Aceragen | In-process research and development costs (IPR&D)
Business Acquisition
Acquisition Date Fair Value	71,600
Impairment of intangible assets	(4,600)
Carrying Value	67,000
Aceragen | ACG-701 for Cystic Fibrosis
Business Acquisition
Acquisition Date Fair Value	50,700
Impairment of intangible assets	(2,600)
Carrying Value	48,100
Aceragen | ACG-701 for Melioidosis
Business Acquisition
Acquisition Date Fair Value	14,900
Carrying Value	14,900
Aceragen | ACG-801 for Farber Disease
Business Acquisition
Acquisition Date Fair Value	6,000
Impairment of intangible assets	(2,000)
Carrying Value	$ 4,000

Business Acquisition - Pro Form

Business Acquisition - Pro Forma Financial Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Business Acquisition
Net revenues	$ 5,688
Net loss	$ (7,354)

Fair Value Measurements - Trans

Fair Value Measurements - Transfers Between Levels (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) item	Dec. 31, 2022 USD ($)
Fair Value Measurements
Fair value of assets transfers from level 1 to level 2	$ 0
Fair value of assets transfers from level 2 to level 1	0
Fair value of liabilities transfers from level 1 to level 2	0
Fair value of liabilities transfers from level 2 to level 1	0
Fair value of assets transfers into level 3	0
Fair value of assets transfers out of level 3	0
Fair value of liabilities transfers into level 3	0
Fair value of liabilities transfers out of level 3	0
Intangible Assets
Goodwill	$ 4,629	$ 11,100
Number of reporting units | item	1
ACG-701 for Cystic Fibrosis | Level 3 fair value measurement
Intangible Assets
Carrying value	$ 50,700
Indefinite-lived intangible assets excluding goodwill, fair value	48,100
ACG-701 for Melioidosis
Intangible Assets
Goodwill	11,100
Goodwill fair value	4,600
ACG-801 for Farber Disease | Level 3 fair value measurement
Intangible Assets
Carrying value	6,000
Indefinite-lived intangible assets excluding goodwill, fair value	$ 4,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	$ 2,118	$ 12,044
Total Liabilities	34,800	37,119
Warrant liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Liabilities		2,819
Series X preferred stock liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Liabilities	34,800	34,300
Cash
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash equivalents - money market funds	500	3,342
Money market funds
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash equivalents - money market funds	1,618	8,702
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	2,118	12,044
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Cash
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash equivalents - money market funds	500	3,342
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Money market funds
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash equivalents - money market funds	1,618	8,702
Level 3 fair value measurement
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Liabilities	34,800	37,119
Level 3 fair value measurement | Warrant liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Liabilities		2,819
Level 3 fair value measurement | Series X preferred stock liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Liabilities	$ 34,800	$ 34,300

Fair Value Measurements - Ass_2

Fair Value Measurements - Assets and Liabilities at Fair Value Changes in Level 3 Liabilities (Details) - Fair Value, Measurements, Recurring $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Warrant liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Beginning balance	$ 2,819
Change in fair value	874
Reclassification to stockholders' equity (1)	(3,693)
Future tranche right liability
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Beginning balance	34,300
Change in fair value	500
Ending balance	$ 34,800

Accrued Expenses (Details)

Accrued Expenses (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) person	Dec. 31, 2022 USD ($)
Accrued Expenses
Payroll and related costs	$ 339	$ 1,886
Clinical and nonclinical trial expenses	1,576	2,106
Professional and consulting fees	1,041	1,637
Restructuring and other costs (1)	2,882	2,327
Acquisition-related costs	1,144	1,666
Other	216	289
Total accrued expenses	7,198	$ 9,911
Salary continuation severance benefits	$ 1,300
Number of former executives | person	2

Series X Preferred Stock Liab_2

Series X Preferred Stock Liability (Details)	3 Months Ended
	Mar. 31, 2023 shares
Series X preferred stock | Aceragen
Stock issued (in shares)	5

Acquisition Obligation (Details

Acquisition Obligation (Details) $ in Thousands		3 Months Ended
	Jan. 31, 2023 USD ($) D	Dec. 31, 2022 USD ($)	Mar. 31, 2023 USD ($)
Business Acquisition
Acquisition obligation, net		$ 6,078	$ 6,300
Convertible Notes
Business Acquisition
Annual interest rate	12%
Aggregate amount	$ 5,900
Convertible Notes and the Promissory Notes, the "January 2023 Notes
Business Acquisition
Annual interest rate	12%
Aggregate amount	$ 400
Consecutive trading days | D	15
Accretion of discounts	$ 200
Aceragen
Business Acquisition
Aggregate future payment			7,800
Acquisition obligation, net			6,300
Acquisition obligation, net			1,500
Fair value of acquisition obligation		7,800	7,500
Payment on debts		$ 1,500
Deferred acquisition obligation			$ 6,000
Annual interest rate			12%

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock (Details) - Series Z Redeemable Convertible Preferred Stock - shares	3 Months Ended
	Mar. 31, 2023	Jan. 17, 2023
Redeemable Convertible Preferred Stock
Conversion of common stock	58.82
Temporary Equity, preferred stock, shares outstanding		80,656
Convertible preferred stock		4,744,467
Aceragen
Redeemable Convertible Preferred Stock
Shares issued during the acquisitions	80,656

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
"At-The-Market" Equity Program
Class of Stock
Stock issued (in shares)	0	0

Stockholders' Equity - Common a

Stockholders' Equity - Common and Preferred Stock Warrants (Details) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Class of Warrant or Right
Number of Shares	1,339,245	517,284
Weighted-Average Exercise Price	$ 17.58	$ 17.58
Equity Classified Warrants
Class of Warrant or Right
Number of Shares	1,339,245	503,069
May 2013 Warrants
Class of Warrant or Right
Number of Shares	908	908
Weighted-Average Exercise Price	$ 1.36	$ 1.36
September 2013 Warrants
Class of Warrant or Right
Number of Shares	241	241
Weighted-Average Exercise Price	$ 1.36	$ 1.36
February 2014 Warrants
Class of Warrant or Right
Number of Shares	128	128
Weighted-Average Exercise Price	$ 1.36	$ 1.36
April 2020 Private Placement first closing warrants
Class of Warrant or Right
Number of Shares	178,794	178,794
Weighted-Average Exercise Price	$ 38.76	$ 38.76
April 2020 Private Placement second closing warrants
Class of Warrant or Right
Number of Shares	80,801	80,801
Weighted-Average Exercise Price	$ 46.07	$ 46.07
July 2020 Private Placement first closing warrants
Class of Warrant or Right
Number of Shares	162,601	162,601
Weighted-Average Exercise Price	$ 43.86	$ 43.86
Assumed Legacy Aceragen common stock warrants
Class of Warrant or Right
Number of Shares	915,772	79,596
Weighted-Average Exercise Price	$ 7.82	$ 7.82
Liability Classified Warrants
Class of Warrant or Right
Number of Shares		14,215
Assumed Legacy Aceragen Series Z Warrants
Class of Warrant or Right
Number of Shares		14,215
Weighted-Average Exercise Price	$ 460	$ 460

Stockholders' Equity - Warrant

Stockholders' Equity - Warrant Activity (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Class of Warrant or Right
Beginning balance	517,284
Conversion	821,961
Ending balance	1,339,245
Warrant exercise price beginning balance | $ / shares	$ 17.58
Warrant exercise price per converted share | $ / shares	7.82
Warrant exercise price ending balance | $ / shares	$ 17.58
Series Z Warrants
Class of Warrant or Right
Beginning balance	14,215
Conversion	(14,215)
Common stock warrants
Class of Warrant or Right
Beginning balance	503,069
Conversion	836,176
Ending balance	1,339,245

Government Contracts Revenue (D

Government Contracts Revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) contract	Mar. 31, 2022 USD ($)
Government Contracts Revenue
Number of in process contracts | contract	3
Aggregate contract value	$ 46,300
Contract value	18,600
Remaining contractual value	27,700
Government contracts revenue	2,470	$ 0
Performance obligation	0
Defense Threat Reduction Agency
Government Contracts Revenue
Remaining contractual value	27,600
Government contracts revenue	$ 2,400

Clinical Funding, Collaborati_2

Clinical Funding, Collaboration and License Agreements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Research and development	$ 4,993	$ 1,784
Scriptr Global, Inc. | Research and Development Plans and Designation of Development Candidates
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Research and development	$ 0	$ 300

Stock-Based Compensation - Equi

Stock-Based Compensation - Equity Incentive Plans (Details) - shares	3 Months Ended
	Mar. 31, 2023	Jan. 12, 2023	Dec. 31, 2022	Sep. 28, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant of inducement stock option	19,116
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding	17,201		19,096
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance		194,456
Options outstanding under earlier plans	271,025
2013 Stock Incentive Plan | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding	26,447
2021 Legacy Aceragen Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares authorized for issuance under stock purchase plan				0
Options outstanding under earlier plans	1,068,004
2022 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance		1,388,235
Common stock options outstanding	295,000
Common shares available for grant	1,319,206
2008 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding under earlier plans	4,908

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Purchase Plans (Details) - $ / shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of share-based compensation expense	15%
Weighted average grant date fair value of options granted during the period (per share)	$ 3.49	$ 7.14
2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares authorized for issuance under stock purchase plan	59,558
Common shares available for grant	39,048

Stock-Based Compensation - Acco

Stock-Based Compensation - Accounting for Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	$ 1,231	$ 545
Research and development
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	500	95
Research and development | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation		6
Research and development | Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	500	89
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	731	450
General and administrative | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation		2
General and administrative | Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	$ 731	$ 448

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used in Determining Fair Value of Stock Options (Details) - $ / shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Stock-Based Compensation
Options to purchase common stock granted to employees and directors	321,900	11,658
Average risk free interest rate	3.90%	1.30%
Expected lives (years)	3 years 1 month 6 days	3 years 9 months 18 days
Expected volatility	106%	105%
Weighted average exercise price (per share)	$ 5.21	$ 10.20

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award
Granted, Weighted Average Exercise Price	$ 5.21	$ 10.20
Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Unrecognized compensation cost related to nonvested stock-based compensation	$ 4,200
Weighted average remaining period over which unrecognized compensation expense will be recognized	2 years 10 months 24 days
Common Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Options, Outstanding, Beginning Balance	406,174
Granted	321,900
Exercised	(3,458)
Conversion of preferred stock options to common stock options	994,399
Forfeited	(43,565)
Expired	(17,397)
Options, Outstanding, Ending Balance	1,658,053		406,174
Exercisable, Ending Balance	593,192
Weighted Average Exercise Price, Beginning Balance	$ 83
Granted, Weighted Average Exercise Price	5.21
Conversion of preferred stock options to common stock options, Weighted Average Exercise Price	6.91
Exercised, Weighted Average Exercise Price	2.21
Forfeited, Weighted Average Exercise Price	7.94
Expired, Weighted Average Exercise Price	2.21
Weighted Average Exercise Price, Ending Balance	25.26		$ 83
Exercisable, Weighted Average Exercise Price	$ 57.65
Outstanding, Weighted Average Remaining Contractual Term	8 years 2 months 12 days		6 years 1 month 6 days
Exercisable, Weighted Average Remaining Contractual Term	6 years 6 months
Outstanding, Intrinsic Value	$ 20		$ 102
Exercisable, Intrinsic Value	$ 10
Preferred Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Options, Outstanding, Beginning Balance	17,522
Exercised	(617)
Conversion of preferred stock options to common stock options	(16,905)
Options, Outstanding, Ending Balance			17,522
Weighted Average Exercise Price, Beginning Balance	$ 397.02
Conversion of preferred stock options to common stock options, Weighted Average Exercise Price	406.76
Exercised, Weighted Average Exercise Price	$ 130
Weighted Average Exercise Price, Ending Balance			$ 397.02
Outstanding, Weighted Average Remaining Contractual Term			9 years 1 month 6 days
Outstanding, Intrinsic Value			$ 1,073

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Unit Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Restricted Stock Unit Activity, Weighted-Average Grant Date Fair Value
Share-based Compensation	$ 1,231	$ 545
Restricted stock units
Restricted Stock Unit Activity, Number of Shares
Nonvested shares, Beginning Balance	19,096
Cancelled	(294)
Vested	(1,601)
Nonvested shares, Ending Balance	17,201
Restricted Stock Unit Activity, Weighted-Average Grant Date Fair Value
Nonvested shares, Weighted Average Grant Date Fair Value, Beginning Balance	$ 10.73
Nonvested shares, Weighted Average Grant Date Fair Value, Ending Balance	$ 7.54
Performance Shares [Member]
Restricted Stock Unit Activity, Number of Shares
Nonvested shares, Beginning Balance	29,814
Cancelled	(6,030)
Vested	(14,538)
Nonvested shares, Ending Balance	9,246
Restricted Stock Unit Activity, Weighted-Average Grant Date Fair Value
Nonvested shares, Weighted Average Grant Date Fair Value, Beginning Balance	$ 26.14
Nonvested shares, Weighted Average Grant Date Fair Value, Ending Balance	$ 26.14

Stock-Based Compensation - Re_2

Stock-Based Compensation - Restricted Stock Activity (Details)	3 Months Ended
	Mar. 31, 2023 shares
Restricted Common Stock
Restricted Stock Unit Activity, Number of Shares
Nonvested shares, Beginning Balance	15,432
Conversion of common stock	75,471
Cancelled	(7,962)
Vested	(6,386)
Nonvested shares, Ending Balance	76,555
Restricted Series Z Preferred Stock
Restricted Stock Unit Activity, Number of Shares
Nonvested shares, Beginning Balance	2,756
Conversion of common stock	(1,283)
Cancelled	(1,426)
Vested	(47)

Related Party Transactions - Ov

Related Party Transactions - Overview of Related Parties (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Sep. 27, 2022	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Oct. 25, 2021
Related Party Transactions
Exercise price of warrants		$ 17.58		$ 17.58
Board fees paid in stock in lieu of director board and committee fees			$ 0.1
Common stock issued in lieu of board fees		0	2,420
Pillar Investment Entities
Related Party Transactions
Aggregate common shares		985,204
Pillar Investment Entities | Warrant, Tranche One
Related Party Transactions
Number of Shares		178,794
Exercise price of warrants		$ 38.76
Pillar Investment Entities | Warrant, Tranche Two
Related Party Transactions
Number of Shares		162,601
Exercise price of warrants		$ 43.86
Pillar Investment Entities | Warrant, Tranche Three
Related Party Transactions
Number of Shares		80,801
Exercise price of warrants		$ 46.07
NovaQuest
Related Party Transactions
Capital contributions committed					$ 20
Proceeds from related party	$ 20
NovaQuest | Common Stock Warrants
Related Party Transactions
Warrants right to purchase		909,326
NovaQuest | Common stock
Related Party Transactions
Number of Shares		830,294
NovaQuest | Series X convertible preferred stock
Related Party Transactions
Convertible preferred stock held by related party		5
NovaQuest | Series Z convertible preferred stock
Related Party Transactions
Warrants held to purchase temporary shares		14,115

Net Loss per Common Share - Ant

Net Loss per Common Share - Antidilutive securities (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive securities
Total antidilutive securities	3,100,314	829,451
Common stock options
Antidilutive securities
Total antidilutive securities	1,658,053	283,526
Restricted stock units and restricted stock awards
Antidilutive securities
Total antidilutive securities	103,002	32,253
Common stock warrants
Antidilutive securities
Total antidilutive securities	1,339,245	513,658
Convertible preferred stock
Antidilutive securities
Total antidilutive securities	14	14

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Events - USD ($)		3 Months Ended
	Apr. 28, 2023	Jun. 30, 2023
Subsequent Events
Percentage of employees terminated	80%
Percentage of the workforce of persons temporarily furloughed	46%
Minimum amount of base salary an executive officer is required to defer	$ 200,000
Restructuring charges		$ 4,600,000