Cyclerion Therapeutics (CYCN) 10-Q 11 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 01, 2023
Cover [Abstract]
Entity Registrant Name	CYCLERION THERAPEUTICS, INC.
Document Type	10-Q
Document Period End Date	Mar. 31, 2023
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		43,524,894
Entity Central Index Key	0001755237
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Entity Tax Identification Number	83-1895370
Entity File Number	001-38787
Entity Incorporation, State or Country Code	MA
Entity Address, Address Line One	245 First Street
Entity Address, Address Line Two	18th Floor
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	857
Local Phone Number	327-8778
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	CYCN
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 7,169	$ 13,382
Accounts receivable	96	96
Prepaid expenses	567	805
Other current assets	503	537
Total current assets	8,335	14,820
Operating lease right-of-use asset	1,171	1,218
Other assets	1,950	2,041
Total assets	11,456	18,079
Current liabilities:
Accounts payable	3,925	2,970
Accrued research and development costs	1,605	2,275
Accrued expenses and other current liabilities	2,001	2,382
Total current liabilities	7,531	7,627
Commitments and contingencies (Note 6)	0	0
Stockholders' equity
Common stock, no par value, 400,000,000 shares authorized and 43,524,894 issued and outstanding at March 31, 2023 and 400,000,000 shares authorized and 43,518,724 issued and outstanding at December 31, 2022	0	0
Paid-in capital	270,052	269,626
Accumulated deficit	(266,108)	(259,154)
Accumulated other comprehensive loss	(19)	(20)
Total stockholders' equity	3,925	10,452
Total liabilities and stockholders' equity	$ 11,456	$ 18,079

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	43,524,894	43,518,724
Common stock, shares outstanding	43,524,894	43,518,724

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues:
Revenue from development agreement	$ 0	$ 225
Revenue from grants	0	486
Total revenues	0	711
Cost and expenses:
Research and development	3,773	9,743
General and administrative	3,269	3,952
Total cost and expenses	7,042	13,695
Loss from operations	(7,042)	(12,984)
Interest and other income (expense), net	88	6
Net loss	$ (6,954)	$ (12,978)
Net loss per share:
Net loss per share - diluted	$ (0.16)	$ (0.30)
Net loss per share - basic	$ (0.16)	$ (0.30)
Earnings Per Share, Basic, Other Disclosure [Abstract]
Weighted Average Number of Shares Outstanding, Basic	43,521	43,425
Weighted Average Number of Shares Outstanding, Diluted	43,521	43,425
Other comprehensive loss:
Net loss	$ (6,954)	$ (12,978)
Other comprehensive loss:
Foreign currency translation adjustment gain	1	(1)
Comprehensive loss	$ (6,953)	$ (12,978)

Condensed Consolidated and Comb

Condensed Consolidated and Combined Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common stock	Paid-in capital	Accumulated deficit	Accumulated other comprehensive loss
Beginning balance at Dec. 31, 2021	$ 48,246		$ 263,345	$ (215,076)	$ (23)
Beginning balance (in shares) at Dec. 31, 2021		43,410,185
Net loss	(12,978)			(12,978)
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan (in shares)		38,175
Share-based compensation expense related to issuance of stock options and RSUs to employees and employee stock purchase plan	1,476		1,476
Share‑based compensation expense related to issuance of stock options to non-employees	291		291
Foreign currency translation adjustment gain	(1)				(1)
Ending balance at Mar. 31, 2022	37,034		265,112	(228,054)	(24)
Ending balance (in shares) at Mar. 31, 2022		43,448,360
Beginning balance at Dec. 31, 2022	$ 10,452		269,626	(259,154)	(20)
Beginning balance (in shares) at Dec. 31, 2022	43,518,724	43,518,724
Net loss	$ (6,954)			(6,954)
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan	0
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan (in shares)		6,170
Share-based compensation expense related to issuance of stock options and RSUs to employees and employee stock purchase plan	416		416
Share‑based compensation expense related to issuance of stock options to non-employees	10		10
Foreign currency translation adjustment gain	1				1
Ending balance at Mar. 31, 2023	$ 3,925		$ 270,052	$ (266,108)	$ (19)
Ending balance (in shares) at Mar. 31, 2023	43,524,894	43,524,894

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (6,954)	$ (12,978)
Adjustments to reconcile net loss to net cash (used in) operating activities:
Depreciation and amortization	0	48
Share-based compensation expense	426	1,767
Changes in operating assets and liabilities:
Accounts receivable	0	(127)
Prepaid expenses	238	(79)
Other current assets	34	(9)
Operating lease assets	47	46
Other assets	91	91
Accounts payable	955	691
Accrued research and development costs	(670)	(1,815)
Accrued expenses and other current liabilities	(381)	(470)
Net cash (used in) operating activities	(6,214)	(12,835)
Effect of exchange rate changes on cash and cash equivalents	1	(1)
Net decrease in cash, cash equivalents and restricted cash	(6,213)	(12,836)
Cash, cash equivalents and restricted cash, beginning of period	13,382	53,961
Cash, cash equivalents and restricted cash, end of period	$ 7,169	$ 41,125

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	1. Nature of Business Nature of Operations Cyclerion Therapeutics, Inc. (“Cyclerion”, the “Company” or “we”) is a biopharmaceutical company on a mission to develop treatments for serious diseases. Our portfolio includes novel soluble guanylate cyclase ("sGC") stimulators that modulate a key node in a fundamental signaling network in both the central nervous system ("CNS") and the periphery. The nitric oxide ("NO") soluble guanylate cyclase ("sGC") cyclic guanosine monophosphate ("cGMP") signaling pathway is a fundamental mechanism that precisely controls key aspects of physiology throughout the body. The NO-sGC-cGMP pathway, regulates diverse and critical biological functions including mitochondrial function, neuronal function, inflammation, and hemodynamics. Although this pathway has been successfully targeted with several drugs in the periphery, this mechanism has yet to be fully leveraged therapeutically, particularly in the CNS, where impaired NO-sGC-cGMP signaling is believed to play an important role in the pathogenesis of many neurodegenerative and neuropsychiatric diseases. Zagociguat is a clinical-stage CNS-penetrant sGC stimulator that has shown rapid improvement in cerebral blood flow, functional brain connectivity, brain response to visual stimulus, cognitive performance, and biomarkers associated mitochondrial function and inflammation in clinical studies. CY 3018 is a CNS-targeted sGC stimulator that preferentially localizes to the brain and has a pharmacology profile that suggests its potential for the treatment of neuropsychiatric diseases and disorders. Praliciguat is a systemic sGC stimulator that is licensed to Akebia Therapeutics, Inc. ("Akebia") and being advanced in rare kidney disease. Olinciguat is a clinical-stage vascular sGC stimulator that the Company intends to out-license for cardiovascular diseases. Cyclerion is actively evaluating the best combination of capital, capabilities, and transactions available to it to advance the development of zagociguat and its other clinical development candidates and to maximize shareholder value. Cyclerion GmbH, a wholly owned subsidiary, was incorporated in Zug, Switzerland on May 3, 2019. The functional currency is the Swiss franc. Cyclerion Securities Corporation, a wholly owned subsidiary, was incorporated in Massachusetts on November 15, 2019 and was granted securities corporation status in Massachusetts for the 2019 tax year. Cyclerion Securities Corporation has no employees. Company Overview The Company’s mission is to develop treatments for serious CNS diseases. Zagociguat is an orally administered CNS-penetrant sGC stimulator. As an sGC stimulator, zagociguat amplifies endogenous NO signaling by acting as a positive allosteric modulator to sensitize the sGC enzyme to NO and increase the production of cGMP, and thereby amplify endogenous NO signaling. By compensating for deficient NO-sGC-cGMP signaling zagociguat may have broad therapeutic potential as a treatment for people with serious diseases. On January 13, 2020, we announced positive results from our Phase 1 first-in-human study that provided the foundation for continued development of zagociguat. The results from this study indicate that zagociguat was well tolerated. Pharmacokinetic data, obtained from both blood and cerebral spinal fluid ("CSF"), support once-daily dosing, with or without food, and demonstrated zagociguat penetration of the blood-brain-barrier with CSF concentrations expected to be pharmacologically active. On October 14, 2020, we announced positive topline results from our zagociguat Phase 1 translational pharmacology study in healthy elderly participants. Treatment with zagociguat for 15-days in this 24-subject study confirmed and extended results seen in the earlier first-in-human Phase 1 study: once daily oral treatment demonstrated blood-brain barrier penetration with expected CNS exposure and target engagement. Results also showed significant improvements in neurophysiological and objective performance measures as well as decreases in inflammatory biomarkers associated with aging and neurodegenerative diseases. Zagociguat was safe and generally well tolerated in the study. These results, together with nonclinical data, supported the continued development of zagociguat as a potential new medicine for serious diseases involving the CNS. On June 10, 2022, we announced positive topline clinical data for zagociguat in our signal-seeking clinical study for the potential treatment of Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes ("MELAS"). In this open-label, single-arm study of the oral, once-daily sGC stimulator in eight adults aged 18 or older with MELAS, improvements were seen across a range of endpoints reflecting multiple domains of disease activity, including mitochondrial disease-associated biomarkers such as lactate and GDF-15, a broad panel of inflammatory biomarkers, cerebral blood flow, and functional connectivity between neural networks. These positive effects after 29 days of dosing were supported by correlations among several endpoints with each other and with zagociguat plasma concentrations. Zagociguat was well tolerated with no serious or severe adverse events and no events leading to discontinuation. Pharmacokinetics were consistent with the Phase 1 studies in healthy volunteers. The positive data from this study support the potential of zagociguat to provide therapeutic benefit to people living with mitochondrial diseases, including MELAS. On July 28, 2022, we announced positive topline data from our signal-seeking clinical study of zagociguat for the potential treatment of Cognitive Impairment Associated with Schizophrenia ("CIAS"). Data from the 14-day, double blind, randomized, placebo-controlled, multiple-ascending-dose study in 48 adults aged 18-50 with stable schizophrenia on a stable, single atypical antipsychotic regimen demonstrated that once-daily zagociguat was safe and well tolerated, with no reports of serious adverse events, severe adverse events, or treatment discontinuation due to adverse events. We further announced that study data demonstrated a strong effect on cognitive performance after two weeks of 15mg once-daily dosing and that positive movements on inflammatory biomarkers were also observed. These signals on exploratory endpoints are consistent with pro-cognitive and anti-inflammatory effects of zagociguat observed in preclinical studies and prior clinical trials and support the further development of oral, once-daily zagociguat. In October 2022, the WHO International Nonproprietary Names committee and the United States Adopted Name council selected zagociguat as a nonproprietary name for CY6463. On March 22, 2023, we announced that given the significant capital and capabilities necessary to ensure that the MELAS Phase 2b study is executed efficiently and with the highest quality, and the currently unfavorable capital market conditions, we are actively evaluating the best combination of capital, capabilities, and transactions available to us to advance the development of zagociguat and our other clinical development candidates and to maximize shareholder value. On March 31, 2023, we entered into a stock purchase agreement with the Company's Chief Executive Officer (the "CEO") pursuant to which the CEO will make an equity investment in the Company of $ 5 million in cash for common stock or nonvoting convertible preferred stock of the Company, the purchase price, consistent with Nasdaq rules, to be at or above the market price at the time of signing that agreement. The closing of the equity investment will take place six business days after the signing of the Asset Purchase Agreement (as defined below), or May 11, 2023. On May 11, 2023, the Company entered into an Asset Purchase Agreement (the "Asset Purchase Agreement”) with an investor group which includes Peter Hecht, the Company's Chief Executive Officer ("CEO"), JW Celtics Investment Corp. (“Buyer Parent”) and JW Cycler Inc. (“Buyer”). Pursuant to the terms of the Asset Purchase Agreement and subject to the approval by the Company's shareholders, the Company will receive proceeds of $ 8 million as cash consideration, reimbursement for certain operating expenses related to zagociguat and CY3018 for the period between signing and closing of the transaction and 10 % of all of Buyer Parent's outstanding equity securities upon the successful closing of the transaction. On May 11, 2023, we announced topline data from our signal- seeking clinical study of zagociguat for the potential treatment of Alzheimer's disease with vascular pathology ("ADv"), which study was supported in part by a $2 million grant from the Alzheimer's Association's Part the Cloud-Gates Partnership Grant Program (the "PTC Grant") . This exploratory, randomized, placebo-controlled, study of oral once-daily zagociguat was designed to evaluate safety, tolerability, and pharmacokinetics as well as explore the impact of zagociguat on biomarkers and cognitive performance over a twelve-week dosing period. The total number of enrolled participants was capped at 12 participants due to challenges associated with enrollment. Data from this study show that the safety and tolerability of profile once-daily zagociguat was consistent with prior studies. Given the small number of participants we are unable to draw any conclusions from the data generated in the study. CY3018 is a CNS-targeted sGC stimulator in preclinical development that preferentially localizes to the brain and has a pharmacology profile that suggests its potential for the treatment of neuropsychiatric diseases and disorders. Praliciguat is an orally administered, once-daily systemic sGC stimulator. On June 3, 2021, we entered into a license agreement with Akebia relating to the exclusive worldwide license to Akebia of our rights to the development, manufacture, medical affairs and commercialization of pharmaceutical products containing praliciguat and other related products and forms thereof enumerated in such agreement. Cyclerion is eligible to receive up to $ 585 million in total potential future development, regulatory, and commercialization milestone payments. Cyclerion is also eligible to receive tiered, sales-based royalties ranging from single-digit to high-teen percentages. Olinciguat is an orally administered, once-daily, vascular sGC stimulator that was evaluated in a Phase 2 study of participants with sickle cell disease. We released topline results from this study in October 2020. We intend to out-license olinciguat to an entity with strong cardiovascular and/or cardiopulmonary capabilities. At-the-Market Offering On July 24, 2020, the Company filed a Registration Statement on Form S-3 (the "Shelf") with the Securities and Exchange Commission (the “SEC”) in relation to the registration of common stock, preferred stock, debt securities, warrants and units of any combination thereof for an aggregate initial offering price not to exceed $ 150.0 million. The Shelf was declared effective as of July 31, 2020. On September 3, 2020, the Company entered into a Sales Agreement (the “Sales Agreement”) with Jefferies LLC (“Jefferies”) with respect to an at-the-market offering (the “ATM Offering”) under the Shelf. Under the ATM Offering, the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, having an aggregate offering price of up to $ 50.0 million through Jefferies as its sales agent. The Company will pay Jefferies cash commissions of 3.0 percent of the gross proceeds of sales of common stock under the Sales Agreement. The Company has sold 3,353,059 shares of its common stock for net proceeds of $ 12.5 million under the ATM Offering since entering into the Sales Agreement. No shares of common stock have been issued or sold under the ATM Offering during the three months ended March 31, 2023. Basis of Presentation The condensed consolidated financial statements and the related disclosures are unaudited and have been prepared in accordance with accounting principles generally accepted in the U.S. Additionally, certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2022, which was filed with the Securities and Exchange Commission on March 22, 2023. In the opinion of management, the unaudited interim condensed consolidated financial statements reflect all normal recurring adjustments considered necessary for a fair presentation of the Company’s financial position and the results of its operations for the interim periods presented. The results of operations for the three months ended March 31, 2023 and 2022 are not necessarily indicative of the results that may be expected for the full year or any other subsequent interim period. The condensed consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries, Cyclerion GmbH, and Cyclerion Securities Corporation. All significant intercompany accounts and transactions have been eliminated in the preparation of the accompanying condensed consolidated financial statements. Going Concern At each reporting period, in accordance with Accounting Standards Codification ("ASC") 205-40, Going Concern, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The Company’s evaluation entails analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs and comparing those needs to the current cash and cash equivalent balances. The Company is required to make certain additional disclosures if it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about the Company’s ability to continue as a going concern. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. In performing its analysis, management excluded certain elements of its operating plan that cannot be considered probable. Under ASC 205-40, the future receipt of potential funding from future partnerships, equity or debt issuances and the potential milestones from the Akebia agreement cannot be considered probable at this time because these plans are not entirely within the Company’s control and/or have not been approved by the Board of Directors as of the date of these consolidated financial statements. The Company’s expectation to generate negative operating cash flows in the future and the need for additional funding to support its planned operations, raise substantial doubt regarding the Company’s ability to continue as a going concern for a period of one year after the date that these consolidated financial statements are issued. Management's plans to alleviate the conditions that raise substantial doubt include reduced spending, and the pursuit of additional capital. Management has concluded the likelihood that its plan to successfully obtain sufficient funding from one or more of these sources, or adequately reduce expenditures, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about the Company's ability to continue as a going concern for a period of at least 12 months from the date of issuance of these consolidated financial statements. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above. Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard On June 1, 2022, the Company received a notice from the Nasdaq Stock Market ("Nasdaq") notifying the Company that, for the last 30 consecutive business days, the closing bid price for the Company's common stock listed on Nasdaq has been below the minimum $ 1.00 per share required for continued listing on the Nasdaq Global Select Market pursuant to Nasdaq Listing Rule 5450(a)(1) (the "Bid Price Requirement"). In accordance with Nasdaq Listing Rule 5810(c)(3)(A), the Company was provided a period of 180 calendar days, or until November 28, 2022, to regain compliance with the Bid Price Requirement. The Company did not regain compliance with the Bid Price Requirement by the initial compliance date. On November 29, 2022, Nasdaq notified the Company that it is eligible for an additional 180 calendar day period, or until May 29, 2023 (the "Extended Compliance Date"), to regain compliance with the Bid Price Requirement. Nasdaq’s determination was based on the Company meeting the continued listing requirement for market value of publicly held shares and all other applicable requirements for initial listing on the Nasdaq Capital Market with the exception of the Bid Price Requirement, and the Company’s written notice of its intention to cure the deficiency during the second compliance period by effecting a reverse stock split, if necessary. Effective November 25, 2022, the Company transferred its listing of the Company’s common stock from the Nasdaq Global Market to the Nasdaq Capital Market, a continuous trading market that operates in substantially the same manner as the Nasdaq Global Market. The Company’s common stock continues to trade under the symbol “CYCN”. To date, the Company has not regained compliance with the Bid Price Requirement. If at any time before May 29, 2023, the bid price of the Company's common stock closes at a $ 1.00 per share or more for a minimum of 10 consecutive business days, Nasdaq will provide written notification to the Company that it has regained compliance with the Bid Price Requirement. If the Company does not regain compliance with the Bid Price Requirement by the end of the second compliance period, the Company's stock will be subject to delisting. On April 3, 2023, the Company filed with the SEC a definitive proxy statement for its annual meeting of stockholders to be held on May 15, 2023, at which meeting the Company is seeking stockholder approval of a reverse stock split with the primary intent of increasing the price of its common stock to meet the price criteria for continued listing on Nasdaq. The Company intends to monitor the closing bid price of its common stock and may, if appropriate, consider available options to regain compliance with the Bid Price Requirement, including initiating a reverse stock split. However, there can be no assurance on how stockholders will vote on such proposal or that the Company will be able to regain compliance with the Bid Price Requirement or will otherwise be in compliance with other Nasdaq Listing Rules.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The accounting policies of the Company are set forth in Note 2. Summary of Significant Accounting Policies to the consolidated financial statements contained in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2022. Use of Estimates The preparation of consolidated financial statements in accordance with U.S. generally accepted accounting principles ("GAAP") requires the Company’s management to make estimates and judgments that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of expenses during the reported periods. On an ongoing basis, the Company’s management evaluates its estimates, judgments, and methodologies. Significant estimates and assumptions in the consolidated financial statements include those related to revenue, impairment of long-lived assets, valuation procedures for right-of-use ("ROU") assets and operating lease liabilities, income taxes, including the valuation allowance for deferred tax assets, research and development expenses, contingencies, share-based compensation and going concern. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known. New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Except as discussed elsewhere in the notes to the consolidated financial statements, the Company did not adopt any new accounting pronouncements during the three months ended March 31, 2023 that had a material effect on its condensed consolidated financial statements. In June 2016 the FASB issued ASU 2016-13, Financial Instruments-Credit Losses. This standard requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. As a smaller reporting company, ASU 2016-13 will become effective for the Company for fiscal years beginning after December 15, 2022, and early adoption is permitted. The Company adopted ASU 2016-13 in the first quarter of 2023, and the adoption of this standard did not have any impact on the Company's financial position or results of operations No other accounting standards known by the Company to be applicable to it that have been issued by the FASB or other standard-setting bodies and that do not require adoption until a future date are expected to have a material impact on the Company’s condensed consolidated financial statements upon adoption.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments The Company’s cash equivalents are generally classified within Level 1 of the fair value hierarchy. The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values as of March 31, 2023 and December 31, 2022 (in thousands): Fair Value Measurements as of March 31, 2023: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 6,079 $ — $ — $ 6,079 Cash equivalents $ 6,079 $ — $ — $ 6,079 Fair Value Measurements as of December 31, 2022: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 12,357 $ — $ — $ 12,357 Cash equivalents $ 12,357 $ — $ — $ 12,357 During the three months ended March 31, 2023 and 2022, there were no transfers between levels. The fair value of the Company’s cash equivalents, consisting of money market funds, is based on quoted market prices in active markets with no valuation adjustment. The Company believes the carrying amounts of its prepaid expenses and other current assets, restricted cash, accounts receivable, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of these amounts.

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment Property and equipment, net consisted of the following (in thousands): March 31, December 31, 2023 2022 Software 2,174 $ 2,174 Computer equipment — 7 Leasehold improvements — — Property and equipment, gross 2,174 2,181 Less: accumulated depreciation and amortization ( 2,174 ) ( 2,181 ) Property and equipment, net $ — $ — As of March 31, 2023, and December 31, 2022, the Company’s property and equipment was primarily located in Boston, Massachusetts. During the three months ended March 31, 2023 , the Company did not record depreciation and amortization expenses. The company recorded approximately $ 0.1 million of depreciation and amortization expenses for the three months ended March 31, 2022 .

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]
Accrued Expenses and Other Current Liabilities	5. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, December 31, 2023 2022 Accrued incentive compensation $ 362 $ 238 Salaries 248 246 Accrued vacation 186 186 Professional fees 924 835 Accrued severance and benefit costs 141 809 Other 140 68 Accrued expenses and other current liabilities $ 2,001 $ 2,382

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Other Funding Commitments In the normal course of business, the Company enters into contracts with clinical research organizations and other third parties for clinical and preclinical research studies and other services and products for operating purposes. These contracts are generally cancellable, with notice, at the Company’s option and do not have any significant cancellation penalties. Guarantees On September 6, 2018, Cyclerion was incorporated in Massachusetts and its officers and directors are indemnified for certain events or occurrences while they are serving in such capacity. The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification provisions. These typically include agreements with directors and officers, business partners, contractors, clinical sites and customers. Under these provisions, the Company generally indemnifies and holds harmless the indemnified party for losses suffered or incurred by the indemnified party as a result of the Company’s activities. These indemnification provisions generally survive termination of the underlying agreements. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. However, to date the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. As a result, the estimated fair value of these obligations is minimal. Accordingly, the Company did not have any liabilities recorded for these obligations as of March 31, 2023 and December 31, 2022 .

Leases

Leases	3 Months Ended
	Mar. 31, 2023
Leases [Abstract]
Leases	7. Leases In May 2021, the Company signed a 12-month membership agreement to lease space with WeWork at 501 Boylston Street, Boston, Massachusetts, commencing on August 1, 2021. The agreement was extended for six months on August 1, 2022. The 12-month agreement and 6-month extension are accounted for as short-term leases. The Company recorded a de minimis amount and approximately $ 0.1 million, in lease expense associated with the membership agreement during the three months ended March 31, 2023 and 2022, respectively. On September 15, 2020, the Company entered into a Sublease Termination Agreement (the "Sublease Termination Agreement") to terminate its sublease of 15,700 rentable square feet of its leased premises under the Head Lease. Under the terms of the Sublease Termination Agreement, the subtenant was relieved of its obligation to provide future cash rental payments to the Company. The agreements requiring the former subtenant to provide licensed rooms and services to the Company free of charge through the original sublease term survived the sublease termination. The Company gained access to the licensed rooms and services beginning in the third quarter of 2021. The letter of credit security deposit related to the sublease was released. The Company determined that the Sublease Termination Agreement constituted a non-monetary exchange under ASC 845 Nonmonetary Transactions ("ASC 845") where, in return for the free rooms and the services, the Company agreed to terminate its rights and obligations under the sublease agreement. In accordance with ASC 845, the Company determined that the accounting for the transaction should be based on the fair value of assets or services involved. The Company estimated the fair value of the rooms and services to be approximately $ 1.5 million and $ 2.9 million, respectively. The Company determined that the licensed rooms represent a lease under ASC Topic 842, Leases. The Company obtained control of the rooms in the third quarter of 2021 and the prepaid rooms balance of approximately $ 1.4 million was reclassified from other assets to a ROU asset. The related lease expense is recognized on a straight-line basis over the lease term of 8.88 years. The Company recorded $ 0.1 million and $ 0.1 million of lease expense during the three months ended March 31, 2023 and 2022, respectively. The Company determined that the licensed services represent a non-lease component, which is recognized separately from the lease component for this asset class. The expense related to the licensed services is recognized on a straight-line basis over the period the services are received. The Company recorded $ 0.1 million and $ 0.1 million for the three months ended March 31, 2023 and 2022 , respectively. Both the lease expense and services expense are recognized as a component of research and development costs in the condensed consolidated statements of operations and comprehensive loss.

Share-based Compensation Plans

Share-based Compensation Plans	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Share-based Compensation Plans	8. Share-based Compensation Plans In 2019, Cyclerion adopted share-based compensation plans. Specifically, Cyclerion adopted the 2019 Employee Stock Purchase Plan (“2019 ESPP”) and the 2019 Equity Incentive Plan (“2019 Equity Plan”). Under the 2019 ESPP, eligible employees may use payroll deductions to purchase shares of stock in offerings under the plan, and thereby acquire an interest in the future of the Company. The 2019 Equity Plan provides for stock options and restricted stock units (“RSUs”). Cyclerion mirrored two of Ironwood Pharmaceuticals, Inc’s ("Ironwood") existing plans, the Amended and Restated 2005 Stock Incentive Plan (“2005 Equity Plan”) and the Amended and Restated 2010 Employee, Director and Consultant Equity Incentive Plan (“2010 Equity Plan"). These mirror plans were adopted to facilitate the exchange of Ironwood equity awards for Cyclerion equity awards upon the tax-free spin-off of Ironwood's sGC business (the "Separation") as part of the equity conversion. As a result of the Separation and in accordance with the Employee Matters Agreement between Ironwood and Cyclerion entered into as part of the Separation, employees of both companies retained their existing Ironwood vested options and received a pro-rata share of Cyclerion options, regardless of which company employed them post-Separation. For employees that were ultimately employed by Cyclerion, unvested Ironwood options and RSUs were converted to unvested Cyclerion options and RSUs. The following table provides share-based compensation reflected in the Company’s condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2023 and 2022 (in thousands): Three Months Ended 2023 2022 Research and development $ 229 $ 830 General and administrative 197 937 $ 426 $ 1,767 A summary of stock option activity for the three months ended March 31, 2023, is as follows: Weighted Weighted Average Average Average Remaining Intrinsic Number Exercise Contractual Value (in of Options Price Term (Years) thousands) Outstanding as of December 31, 2022 7,311,893 $ 9.23 5.8 20 Granted — 0.00 Exercised — 0.00 Cancelled or forfeited ( 600,887 ) 14.29 Outstanding as of March 31, 2023 6,711,006 $ 8.77 6.1 $ 0 Exercisable at March 31, 2023 4,867,431 $ 11.30 5.2 $ 0 As of March 31, 2023, the unrecognized share-based compensation expense, net of estimated forfeitures, related to all unvested time-based stock options held by the Company’s employees is $ 1.8 million and the weighted average period over which that expense is expected to be recognized is 3.2 years. A summary of RSU activity for the three months ended March 31, 2023 is as follows: Weighted Average Number Grant Date of Shares Fair Value Unvested as of December 31, 2022 815,587 $ 0.77 Granted — — Vested ( 6,170 ) 14.20 Forfeited — — Unvested as of March 31, 2023 809,417 $ 0.66 As of March 31, 2023, the unrecognized share-based compensation expense, net of estimated forfeitures, related to all unvested restricted stock units by the Company’s employees is $ 0.3 million and the weighted-average period over which that expense is expected to be recognized is 0.52 years. The Company has granted to certain employees stock options containing market conditions that vest upon the achievement of specified price targets of the Company’s share price for a period through December 31, 2024. Vesting is measured based upon the average closing price of the Company’s share price for any thirty consecutive trading days, subject to certain service requirements. Stock compensation cost is expensed on a straight-line basis over the derived service period for each stock price target within the award, ranging from approximately 4.0 to 4.6 years. The Company accelerates expense when a stock price target is achieved prior to the derived service period. As of March 31, 2023 there were 300,000 outstanding stock options containing market conditions with a weighted average exercise price of $ 2.01 . As of March 31, 2023 there was $ 0.1 million of unrecognized compensation costs related to stock options containing market conditions, which is expected to be recognized over a weighted-average period of 1 year.

Loss per share

Loss per share	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Loss per share	9. Loss per share Basic and diluted net loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding during the period as follows: Three Months Ended 2023 2022 Numerator: Net loss (in thousands) $ ( 6,954 ) $ ( 12,978 ) Denominator: Weighted average shares used in calculating net loss per share — basic and diluted (in thousands) 43,521 43,425 Net loss per share — basic and diluted $ ( 0.16 ) $ ( 0.30 ) We exclude shares of common stock related to stock options and RSUs from the calculation of diluted net loss per share since the inclusion of such shares would be anti-dilutive. The following table sets forth potential shares that were considered anti-dilutive for the three months ended March 31, 2023 and 2022: Three Months Ended 2023 2022 Stock Options $ 6,711,006 $ 8,270,398 RSUs 809,417 54,629 $ 7,520,423 $ 8,325,027

Defined Contribution Plan

Defined Contribution Plan	3 Months Ended
	Mar. 31, 2023
Retirement Benefits [Abstract]
Defined Contribution Plan	10. Defined Contribution Plan Subsequent to the Separation, the Company adopted a defined contribution 401(k) Savings Plan similar to the plan in place at Ironwood. The plan assets under the Ironwood defined contribution 401(k) Savings Plan were transferred to the Company's plan. Subject to certain IRS limits, eligible employees may elect to contribute from 1 % to 100 % of their compensation. The Company's contributions to the plan are at the sole discretion of the board of directors. Currently, the Company provides a matching contribution of 75 % of the employee’s contributions, up to $ 6,000 annually. Included in compensation expense is approximately $ 0.1 million and $ 0.2 million related to the defined contribution 401(k) Savings Plan for the three months ended March 31, 2023 and 2022 , respectively.

Workforce Reduction

Workforce Reduction	3 Months Ended
	Mar. 31, 2023
Restructuring and Related Activities [Abstract]
Workforce Reduction	11. Workforce Reduction 2022 Workforce Reduction On October 6, 2022, the Company began a reduction of its current workforce by thirteen (13) full-time employees to align its resources with its current priorities of focusing on a mitochondrial disease-focused strategy. The workforce reduction was completed in the fourth quarter of 2022. The Company recorded total costs related to the 2022 Workforce Reduction of approximately $ 1.3 million, including a de minimis amount of stock-based compensation from the modification of certain share-based equity awards. The following table summarizes the accrued liabilities activity recorded in connection with the reduction in workforce for the three months ended March 31, 2023 (in thousands): Amounts Charges Amount Adjustments Amounts 2022 workforce reduction $ ( 809 ) $ — $ 668 $ — $ ( 141 ) Total $ ( 809 ) $ — $ 668 $ — $ ( 141 )

License Agreement

License Agreement	3 Months Ended
	Mar. 31, 2023
License Agreement [Abstract]
License Agreements	12. License Agreement Akebia License Agreement On June 3, 2021, the Company and Akebia entered into a License Agreement (the “Akebia License Agreement”) relating to the exclusive worldwide license by the Company to Akebia of our rights to the development, manufacture, medical affairs and commercialization of pharmaceutical products containing the pharmaceutical compound known as praliciguat and other related products and forms thereof enumerated in the License Agreement (collectively, the “Products”). Pursuant to the Akebia License Agreement, Akebia will be responsible for all future research, development, regulatory, and commercialization activities for the Products. Akebia paid a $ 3.0 million up-front payment to the Company upon signing of the Akebia License Agreement and the Company is eligible to receive additional milestone cash payments of up to $ 12.0 million upon initiation of a Phase 2 clinical trial. Further milestone cash payments by Akebia are scheduled in the Akebia License Agreement based on the initiation of Phase 3 clinical trials in the U.S. for Products for first and second indication, for FDA approvals, for approvals in certain other major markets, and for certain sales milestones. In addition to these cash milestone payments, Akebia will pay the Company tiered royalty payments on net sales in certain major markets at percentages ranging from the mid-single digits to the high-teens, subject to certain reductions and offsets. Pursuant to the Akebia License Agreement, the Company determined the Akebia License Agreement represents a service arrangement under the scope of ASC 606. Given the reversion of the rights under the Akebia License Agreement represents a penalty in substance for a termination by Akebia, the contract term would be the stated term of the Akebia License Agreement. The Company determined that the grant of license to our patents and trademarks, know how transfer, the assignment of regulatory submissions and trademarks and additional knowledge transfer assistance obligations represent a single promise and performance obligation to be transferred to Akebia over time due to the nature of the promises in the contract. The provision of development materials on hand was identified as a separate performance obligation. However, it is immaterial in the context of the contract as the development materials are low value and do not have an alternative use to the Company. The consideration related to sales-based milestone payments, including royalties, will be recognized when the related sales occur as these amounts have been determined to relate predominantly to the license. The Company will re-evaluate the probability of achievement of the milestones and any related constraints each reporting period. Akebia Supply Agreement On August 3, 2021, the Company and Akebia entered into a Supply Agreement (the “Supply Agreement”) relating to the manufacturing by the Company of the Initial Supply of the Drug Product and placebo ("Initial Supply") for Akebia's use pursuant to the Akebia License Agreement. Akebia will pay the Company for the manufacturing costs at mutually agreed upon rates. The Company determined the Supply Agreement has stand-alone value under the scope of ASC 606 and should not be combined with the Akebia License Agreement. Given that the Supply Agreement can be terminated at any time without cause with 30 days notice, the Company deemed the Supply Agreement to be a month-to-month contract. The manufacturing of the Initial Supply by the Company represents a single performance obligation and consideration related to the manufacturing costs will be recognized over time as costs are incurred. The Company recorded approximately $ 0.2 million as revenue from the Supply Agreement in the three months ended March 31, 2022. There was no revenue recognized as part of the Supply Agreement in the three months ended March 31, 2023.

Grant Revenue

Grant Revenue	3 Months Ended
	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Grant Revenue	13. Grant Revenue In August 2021, the Company was approved to receive funding from the PTC Grant for the Phase 2 study of CNS sGC stimulation in AD with vascular features. The granting period was July 1, 2021, to December 31, 2022, and the Company received an award of $ 2 million. The Company determined that this transaction is non-reciprocal as there is not considered to be a commensurate value exchanged with the Alzheimer's Association as the funding provider. Where commensurate value is not exchanged for goods and services provided, a recipient assesses whether the grant is conditional or unconditional. The Company considered all conditions and barriers associated with this grant and determined the grant is conditional and revenue will be recognized upon achieving certain milestones and incurring internal costs specifically covered by this grant. Under ASC 958-605, revenues will be recognized as the Company incurs expenses related to the PTC Grant. The Company has incurred no costs associated with the grant for the three months ended March 31, 2023, compared to approximately $ 0.5 million of expenses associated with the grant for the three months ended March 31, 2022. The Company had a deferred revenue balance of approximately $ 0.1 million related to advance billings as of March 31, 2023 .

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events On May 11, 2023, the Company entered into the Asset Purchase Agreement with an investor group which includes the Company's CEO, Buyer Parent and Buyer. Pursuant to the terms of the Asset Purchase Agreement and subject to the approval by the Company's shareholders, the Company will receive proceeds of $ 8 million as cash consideration, reimbursement for certain operating expenses related to zagociguat and CY3018 for the period between signing and closing of the transaction and 10 % of all of Buyer Parent's outstanding equity securities upon the successful closing of the transaction. The Company will also receive net proceeds of $ 5 million pursuant to a stock purchase agreement with the Company's CEO, which will take place six business days after the signing of the Asset Purchase Agreement.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements and the related disclosures are unaudited and have been prepared in accordance with accounting principles generally accepted in the U.S. Additionally, certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2022, which was filed with the Securities and Exchange Commission on March 22, 2023. In the opinion of management, the unaudited interim condensed consolidated financial statements reflect all normal recurring adjustments considered necessary for a fair presentation of the Company’s financial position and the results of its operations for the interim periods presented. The results of operations for the three months ended March 31, 2023 and 2022 are not necessarily indicative of the results that may be expected for the full year or any other subsequent interim period. The condensed consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries, Cyclerion GmbH, and Cyclerion Securities Corporation. All significant intercompany accounts and transactions have been eliminated in the preparation of the accompanying condensed consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with U.S. generally accepted accounting principles ("GAAP") requires the Company’s management to make estimates and judgments that may affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of expenses during the reported periods. On an ongoing basis, the Company’s management evaluates its estimates, judgments, and methodologies. Significant estimates and assumptions in the consolidated financial statements include those related to revenue, impairment of long-lived assets, valuation procedures for right-of-use ("ROU") assets and operating lease liabilities, income taxes, including the valuation allowance for deferred tax assets, research and development expenses, contingencies, share-based compensation and going concern. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ materially from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known.
New Accounting Pronouncements	New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Except as discussed elsewhere in the notes to the consolidated financial statements, the Company did not adopt any new accounting pronouncements during the three months ended March 31, 2023 that had a material effect on its condensed consolidated financial statements. In June 2016 the FASB issued ASU 2016-13, Financial Instruments-Credit Losses. This standard requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. As a smaller reporting company, ASU 2016-13 will become effective for the Company for fiscal years beginning after December 15, 2022, and early adoption is permitted. The Company adopted ASU 2016-13 in the first quarter of 2023, and the adoption of this standard did not have any impact on the Company's financial position or results of operations No other accounting standards known by the Company to be applicable to it that have been issued by the FASB or other standard-setting bodies and that do not require adoption until a future date are expected to have a material impact on the Company’s condensed consolidated financial statements upon adoption.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of financial assets measured at fair value on a recurring basis and indicating the level of the fair value hierarchy	The Company’s cash equivalents are generally classified within Level 1 of the fair value hierarchy. The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values as of March 31, 2023 and December 31, 2022 (in thousands): Fair Value Measurements as of March 31, 2023: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 6,079 $ — $ — $ 6,079 Cash equivalents $ 6,079 $ — $ — $ 6,079 Fair Value Measurements as of December 31, 2022: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 12,357 $ — $ — $ 12,357 Cash equivalents $ 12,357 $ — $ — $ 12,357

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of property and equipment, net	Property and equipment, net consisted of the following (in thousands): March 31, December 31, 2023 2022 Software 2,174 $ 2,174 Computer equipment — 7 Leasehold improvements — — Property and equipment, gross 2,174 2,181 Less: accumulated depreciation and amortization ( 2,174 ) ( 2,181 ) Property and equipment, net $ — $ —

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, December 31, 2023 2022 Accrued incentive compensation $ 362 $ 238 Salaries 248 246 Accrued vacation 186 186 Professional fees 924 835 Accrued severance and benefit costs 141 809 Other 140 68 Accrued expenses and other current liabilities $ 2,001 $ 2,382

Share-based Compensation Plans

Share-based Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of share-based compensation expense	The following table provides share-based compensation reflected in the Company’s condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2023 and 2022 (in thousands): Three Months Ended 2023 2022 Research and development $ 229 $ 830 General and administrative 197 937 $ 426 $ 1,767
Schedule of stock option activity	A summary of stock option activity for the three months ended March 31, 2023, is as follows: Weighted Weighted Average Average Average Remaining Intrinsic Number Exercise Contractual Value (in of Options Price Term (Years) thousands) Outstanding as of December 31, 2022 7,311,893 $ 9.23 5.8 20 Granted — 0.00 Exercised — 0.00 Cancelled or forfeited ( 600,887 ) 14.29 Outstanding as of March 31, 2023 6,711,006 $ 8.77 6.1 $ 0 Exercisable at March 31, 2023 4,867,431 $ 11.30 5.2 $ 0
Summary of RSU activity	A summary of RSU activity for the three months ended March 31, 2023 is as follows: Weighted Average Number Grant Date of Shares Fair Value Unvested as of December 31, 2022 815,587 $ 0.77 Granted — — Vested ( 6,170 ) 14.20 Forfeited — — Unvested as of March 31, 2023 809,417 $ 0.66

Loss per share (Tables)

Loss per share (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Schedule of basic and diluted earnings per share	Basic and diluted net loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding during the period as follows: Three Months Ended 2023 2022 Numerator: Net loss (in thousands) $ ( 6,954 ) $ ( 12,978 ) Denominator: Weighted average shares used in calculating net loss per share — basic and diluted (in thousands) 43,521 43,425 Net loss per share — basic and diluted $ ( 0.16 ) $ ( 0.30 )
Schedule Of Earnings Per Share Diluted By Common Class	The following table sets forth potential shares that were considered anti-dilutive for the three months ended March 31, 2023 and 2022: Three Months Ended 2023 2022 Stock Options $ 6,711,006 $ 8,270,398 RSUs 809,417 54,629 $ 7,520,423 $ 8,325,027

Workforce Reduction (Tables)

Workforce Reduction (Tables)	3 Months Ended
	Mar. 31, 2023
Restructuring and Related Activities [Abstract]
Schedule of accrued liabilities activity allocated to Cyclerion in connection with the reduction in workforce	The following table summarizes the accrued liabilities activity recorded in connection with the reduction in workforce for the three months ended March 31, 2023 (in thousands): Amounts Charges Amount Adjustments Amounts 2022 workforce reduction $ ( 809 ) $ — $ 668 $ — $ ( 141 ) Total $ ( 809 ) $ — $ 668 $ — $ ( 141 )

Nature of Business (Details)

Nature of Business (Details) $ / shares in Units, $ in Thousands							3 Months Ended
	May 29, 2023 TradingDay $ / shares	May 11, 2023 USD ($)	Nov. 29, 2022 TradingDay	Nov. 28, 2022 TradingDay	Jun. 01, 2022 TradingDay $ / shares	Sep. 03, 2020 USD ($)	Mar. 31, 2023 USD ($) shares	Jul. 24, 2020 USD ($)	Nov. 15, 2019 Employee
Nature of Business
Common stock issued or sold under the ATM Offering							$ 0
Equity investment in cash							$ 5,000
Threshold consecutive business days for which notice received from NASDAQ for not maintaining the minimum bid price | TradingDay					30
Minimum bid price of its common stock | $ / shares					$ 1
Grace period | TradingDay				180
Additional grace period | TradingDay			180
IPO
Nature of Business
Maximum amount of Aggregate initial offering price								$ 150,000
ATM Offering | Jefferies LLC
Nature of Business
Number of common stock sold | shares							3,353,059
Cash commission of gross proceeds of sales of common stock, percentage						3%
Net Proceeds from Issuance of Common Stock							$ 12,500
ATM Offering | Maximum | Jefferies LLC
Nature of Business
Issuance of common stock equity private placement and ATM						$ 50,000
Cyclerion Securities Corporation
Nature of Business
Number of employees | Employee									0
Commercialization milestone payments							$ 585,000
Subsequent Event [Member]
Nature of Business
Health care trust fund, Description		On May 11, 2023, we announced topline data from our signal- seeking clinical study of zagociguat for the potential treatment of Alzheimer's disease with vascular pathology ("ADv"), which study was supported in part by a $2 million grant from the Alzheimer's Association's Part the Cloud-Gates Partnership Grant Program (the "PTC Grant") . This exploratory, randomized, placebo-controlled, study of oral once-daily zagociguat was designed to evaluate safety, tolerability, and pharmacokinetics as well as explore the impact of zagociguat on biomarkers and cognitive performance over a twelve-week dosing period. The total number of enrolled participants was capped at 12 participants due to challenges associated with enrollment. Data from this study show that the safety and tolerability of profile once-daily zagociguat was consistent with prior studies. Given the small number of participants we are unable to draw any conclusions from the data generated in the study.
Cash consideration transferrred		$ 8,000
JW Celtics Investment Corp [Member] | Subsequent Event [Member]
Nature of Business
Outstanding equity securities		10%
Forecast [Member]
Nature of Business
Minimum bid price of its common stock | $ / shares	$ 1
Minimum consecutive business days for which bid price must meet or exceed $1.00 per share to regain compliance | TradingDay	10

Fair Value of Financial Instr_3

Fair Value of Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Cash equivalents:
Total cash equivalents	$ 6,079	$ 12,357
Level 1
Cash equivalents:
Total cash equivalents	6,079	12,357
Money market funds
Cash equivalents:
Total cash equivalents	6,079	12,357
Money market funds | Level 1
Cash equivalents:
Total cash equivalents	$ 6,079	$ 12,357

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Property and Equipment
Property and equipment. gross	$ 2,174		$ 2,181
Less: accumulated depreciation and amortization	(2,174)		(2,181)
Property and equipment, net	0		0
Depreciation and amortization	0	$ 48
Property and Equipment
Property and Equipment
Depreciation and amortization	0	$ 100
Software
Property and Equipment
Property and equipment. gross	$ 2,174		2,174
Computer equipment
Property and Equipment
Property and equipment. gross			$ 7

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accrued Liabilities and Other Liabilities [Abstract]
Accrued incentive compensation	$ 362	$ 238
Salaries	248	246
Accrued vacation	186	186
Professional fees	924	835
Accrued severance and benefit costs	141	809
Other	140	68
Accrued expenses and other current liabilities	$ 2,001	$ 2,382

Leases - Summary (Details)

Leases - Summary (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Aug. 01, 2022	May 31, 2021	Sep. 15, 2020 ft²
Leases
Term of lease	8 years 10 months 17 days
Rentable space terminated from lease agreement (in square feet) | ft²						15,700
Operating lease right-of-use asset	$ 1,171		$ 1,218
Licensed Room
Leases
lease expense	100	$ 100
License And Service
Leases
lease expense	100	100
We Work
Leases
Term of lease				12 months	12 months
Renewal term				6 months
Total lease costs	$ 100	$ 100

Leases - Sublease as Lessor (De

Leases - Sublease as Lessor (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Sep. 15, 2020 ft²
Sublease as lessor
Rentable space terminated from lease agreement (in square feet) | ft²				15,700
Sublease termination agreement estimated fair value of rooms	$ 1,500
Sublease termination agreement estimated fair value of services	2,900
Other current assets	503		$ 537
Prepaid rooms balance reclassified from other assets	$ 1,400
Term of lease	8 years 10 months 17 days
License And Service
Sublease as lessor
lease expense	$ 100	$ 100

Share-based Compensation Plan_2

Share-based Compensation Plans (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) TradingDay $ / shares shares	Mar. 31, 2022 USD ($)	Dec. 31, 2022 $ / shares shares
Share-based Compensation Plans
Share-based compensation	$ 426	$ 1,767
Expected period to recognize the expense	1 year
Unrecognized share-based compensation expense | $	$ 100
outstanding stock options | shares	300,000
weighted average exercise price | $ / shares	$ 2.01
Restricted Stock Units
Share-based Compensation Plans
Unrecognized share-based compensation expense	$ 300
Expected period to recognize the expense	6 months 7 days
Stock options
Share-based Compensation Plans
Unrecognized share-based compensation expense		$ 1,800
Expected period to recognize the expense		3 years 2 months 12 days
Stock options forfeited | shares	600,887
Cancelled or forfeited (in dollars per share) | $ / shares	$ 14.29
outstanding stock options | shares	6,711,006		7,311,893
weighted average exercise price | $ / shares	$ 8.77		$ 9.23
Performance stock options
Share-based Compensation Plans
Threshold consecutive trading days, used as a base for measurement of vesting of stock awards | TradingDay	30
Performance stock options | Minimum [Member]
Share-based Compensation Plans
Expected option term (in years)	4 years
Performance stock options | Maximum
Share-based Compensation Plans
Expected option term (in years)	4 years 7 months 6 days

Share-based Compensation Plan_3

Share-based Compensation Plans - Schedule of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation	$ 426	$ 1,767
Research and development
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation	229	830
General and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation	$ 197	$ 937

Share-based Compensation Plan_4

Share-based Compensation Plans - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Number of Options
Outstanding at end of the year (in shares)	300,000
Weighted Average Exercise Price
Outstanding at end of the year (in dollars per share)	$ 2.01
Stock options
Number of Options
Outstanding at beginning of the year (in shares)	7,311,893
Cancelled or forfeited (in shares)	(600,887)
Outstanding at end of the year (in shares)	6,711,006	7,311,893
Exercisable (in shares)	4,867,431
Weighted Average Exercise Price
Outstanding at beginning of the year (in dollars per share)	$ 9.23
Granted (in dollars per share)	0
Exercised (in dollars per share)	0
Cancelled or forfeited (in dollars per share)	14.29
Outstanding at end of the year (in dollars per share)	8.77	$ 9.23
Exercisable (in dollars per share)	$ 11.30
Weighted Average Remaining Contractual Term (years)
Weighted Average Remaining Contractual Term (years)	6 years 1 month 6 days	5 years 9 months 18 days
Weighted Average Remaining Contractual Term (years)	5 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding	$ 0	$ 20
Aggregate Intrinsic Value, Exercisable	$ 0

Share-based Compensation Plan_5

Share-based Compensation Plans - Summary of RSU Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Number of Shares
Unvested as of December 31, 2021	809,417
Unvested the end of the period (in shares)	809,417
Restricted Stock Units
Number of Shares
Unvested as of December 31, 2021		815,587
Granted (in shares)	0
Vested (in shares)	(6,170)
Forfeited (in shares)	0
Weighted-Average Grant Date Fair Value
Unvested as of December 31, 2021	$ 0.66	$ 0.77
Granted (in dollars per share)	0
Vested (in dollars per share)	14.20
Forfeited (in dollars per share)	0
Unvested restricted common stock at the end of the period (in dollars per share)	$ 0.66

Loss per share (Details)

Loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net loss	$ (6,954)	$ (12,978)	$ (6,954)
Denominator:
Weighted average shares used in calculating net loss per share - basic	43,521	43,425
Weighted average shares used in calculating net loss per share - diluted	43,521	43,425
Net loss per share - basic	$ (0.16)	$ (0.30)
Net loss per share - diluted	$ (0.16)	$ (0.30)

Loss Per Share - Schedule Of Ea

Loss Per Share - Schedule Of Earnings Per Share Diluted By Common Class (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units	$ 7,520,423	$ 8,325,027
Stock options
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units	6,711,006	8,270,398
Restricted Stock Units
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units	$ 809,417	$ 54,629

Defined Contribution Plan (Deta

Defined Contribution Plan (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Defined Contribution Plan
401 (k) Savings Plan	us-gaap:QualifiedPlanMember
Matching contribution (as a percent of employee's contributions)	75%
Maximum amount of employer matching contribution	$ 6,000
Compensation expense related to the defined contribution 401(k) Savings Plan	$ 100,000	$ 200,000
Minimum
Defined Contribution Plan
Percent of compensation eligible employees may elect to contribute	1%
Maximum
Defined Contribution Plan
Percent of compensation eligible employees may elect to contribute	100%

Workforce Reduction (Details)

Workforce Reduction (Details) $ in Thousands		3 Months Ended
	Oct. 06, 2022 USD ($) Employees	Mar. 31, 2023 USD ($)
Restructuring Cost and Reserve [Line Items]
Beginning of period		$ (809)
Charges		0
Amount paid		668
Adjustments		0
End of period		(141)
Workforce Reduction Plan2022 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning of period		(809)
Charges		0
Amount paid		668
Adjustments		0
End of period		$ (141)
Current workforce reductions | October 2022 Current Workforce Reduction
Restructuring Cost and Reserve [Line Items]
Reduction in workforce, number of employees | Employees	13
Restructuring costs	$ 1,300

License Agreement - Additional

License Agreement - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	Jun. 03, 2021	Mar. 31, 2023	Mar. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues		$ 0	$ 711
Akebia Research License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up Front Payment Received	$ 3,000
Additional milestone cash payment	$ 12,000
Akebia Supply Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues		$ 0	$ 200

Grant Revenue (Additional Infor

Grant Revenue (Additional Information) (Details) - USD ($)	3 Months Ended		18 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Revenue Recognition and Deferred Revenue [Abstract]
PTC Grant Award			$ 2,000,000
Allowable Expenses on Grant Revenue	$ 0	$ 500,000
Deferred Revenue	$ 100,000

Subsequent Events (Additional I

Subsequent Events (Additional Information) (Details) - Subsequent Event [Member] $ in Millions	May 11, 2023 USD ($)
Subsequent Event [Line Items]
Cash consideration transferrred	$ 8
Net proceeds	$ 5
JW Celtics Investment Corp [Member]
Subsequent Event [Line Items]
Outstanding equity securities	10%