0000950170-23-009223 | 10-K | XBRL Viewer | Cyclerion Therapeutics INC

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2022	Mar. 19, 2023	Jun. 30, 2022
Cover [Abstract]
Entity Registrant Name	CYCLERION THERAPEUTICS, INC.
Document Type	10-K
Document Period End Date	Dec. 31, 2022
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Public Float			$ 18.8
Entity Common Stock, Shares Outstanding		43,524,894
Entity Central Index Key	0001755237
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Annual 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, 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
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement, to be filed pursuant to Regulation 14A under the Securities Exchange Act of 1934, for its 2023 Annual Meeting of Stockholders are incorporated by reference in Part III of this Form 10-K.
ICFR Auditor Attestation Flag	false
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 13,382	$ 53,961
Accounts receivable	96	100
Prepaid expenses	805	928
Other current assets	537	468
Total current assets	14,820	55,457
Property and equipment, net	0	65
Operating lease right-of-use asset	1,218	1,402
Other assets	2,041	2,407
Total assets	18,079	59,331
Current liabilities:
Accounts payable	2,970	1,828
Accrued research and development costs	2,275	6,353
Accrued expenses and other current liabilities	2,382	2,904
Total current liabilities	7,627	11,085
Commitments and contingencies (Note 6)	0	0
Stockholders' equity
Common stock, no par value, 400,000,000 shares authorized and 43,518,724 issued and outstanding at December 31, 2022 and 400,000,000 shares authorized and 43,410,185 issued and outstanding at December 31, 2021	0	0
Accumulated deficit	(259,154)	(215,076)
Paid-in capital	269,626	263,345
Accumulated other comprehensive loss	(20)	(23)
Total stockholders' equity	10,452	48,246
Total liabilities and stockholders' equity	$ 18,079	$ 59,331

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
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	43,518,724	43,410,185
Common stock, shares outstanding	43,518,724	43,410,185

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenues [Abstract]
Revenue from license agreement	$ 0	$ 3,000
Revenue from development agreement	297	320
Revenue from grants	1,328	622
Total revenues	1,625	3,942
Cost and expenses:
Research and development	31,493	37,636
General and administrative	14,504	20,620
Loss on lease termination	0	881
Total cost and expenses	45,997	59,137
Loss from operations	(44,372)	(55,195)
Gain on extinguishment of debt	0	3,564
Interest and other income (expenses), net	294	(16)
Net loss	$ (44,078)	$ (51,647)
Net loss per share:
Net loss per share - basic	$ (1.01)	$ (1.32)
Net loss per share - diluted	$ (1.01)	$ (1.32)
Weighted average shares used in calculating:
Weighted Average Number of Shares Outstanding, Basic	43,469	39,144
Weighted Average Number of Shares Outstanding, Diluted	43,469	39,144
Other comprehensive loss:
Net loss	$ (44,078)	$ (51,647)
Other comprehensive loss:
Foreign currency translation adjustment gain	3	4
Comprehensive loss	$ (44,075)	$ (51,643)

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Paid in capital	Accumulated deflicit	Accumulated other comprehensive loss
Beginning balance at Dec. 31, 2020	$ 59,493		$ 222,949	$ (163,429)	$ (27)
Beginning balance (in shares) at Dec. 31, 2020		34,047,300
Net loss	(51,647)			(51,647)
Issuance of common stock - 2021 equity private placement and ATM	30,503		30,503
Issuance of common stock - 2021 equity private placement and ATM (in shares)		9,089,047
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan	282		282
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan (in shares)		273,838
Share-based compensation expense related to issuance of stock options and RSUs to employees and employee stock purchase plan	7,915		7,915
Share based compensation expense related to issuance of stock options and RSUs to non employees	1,696		1,696
Foreign currency translation adjustment gain	4				4
Ending balance at Dec. 31, 2021	$ 48,246		263,345	(215,076)	(23)
Ending balance (in shares) at Dec. 31, 2021	43,410,185	43,410,185
Net loss	$ (44,078)			(44,078)
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan	29		29
Issuance of common stock upon exercise of stock options, RSUs and employee stock purchase plan (in shares)		108,539
Share-based compensation expense related to issuance of stock options and RSUs to employees and employee stock purchase plan	5,091		5,091
Share based compensation expense related to issuance of stock options and RSUs to non employees	1,161		1,161
Foreign currency translation adjustment gain	3		0		3
Ending balance at Dec. 31, 2022	$ 10,452		$ 269,626	$ (259,154)	$ (20)
Ending balance (in shares) at Dec. 31, 2022	43,518,724	43,518,724

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (44,078)	$ (51,647)
Adjustments to reconcile net loss to net cash (used in) operating activities:
Depreciation and amortization	65	472
Net loss on disposal of property and equipment	0	6,322
Loss on lease termination	0	881
Gain on extinguishment of debt	0	(3,564)
Share-based compensation expense	6,252	9,611
Changes in operating assets and liabilities:
Accounts receivable	4	(100)
Related party accounts receivable	0	127
Prepaid expenses	123	(112)
Other current assets	(69)	1,244
Operating lease assets	184	(59)
Other assets	366	366
Accounts payable	1,142	679
Related party accounts payable	0	(286)
Accrued research and development costs	(4,078)	4,932
Operating lease liabilities	0	(1,048)
Accrued expenses and other current liabilities	(522)	(4,335)
Net cash (used in) operating activities	(40,611)	(36,517)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	0	(7)
Proceeds from sale of property and equipment	0	1,464
Net cash provided by investing activities	0	1,457
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from equity private placement and ATM	0	30,503
Proceeds from exercises of stock options and ESPP	29	282
Net cash provided by financing activities	29	30,785
Effect of exchange rate changes on cash and cash equivalents	3	4
Net decrease in cash and cash equivalents	(40,579)	(4,271)
Cash and cash equivalents, beginning of period	53,961	58,232
Cash and cash equivalents, end of period	$ 13,382	$ 53,961

Nature of Business

12 Months Ended

Dec. 31, 2022

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 lead internal asset, zagociguat, is a pioneering, central nervous system ("CNS")-penetrant, soluble guanylate cyclase ("sGC") stimulator that has shown rapid improvements across a range of endpoints reflecting multiple domains of disease activity, including mitochondrial disease-associated biomarkers. sGC stimulators are small molecules that act synergistically with nitric oxide ("NO") as positive allosteric modulators of sGC to boost production of cyclic guanosine monophosphate ("cGMP"). cGMP is a key second messenger that, when produced by sGC, regulates diverse and critical biological functions such as mitochondrial function, neuronal function, inflammation, and vascular dynamics.

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 acts as a positive allosteric modulator to sensitize the sGC enzyme to NO, 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 to improve cognition and function in people with serious CNS 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 in inflammatory biomarkers associated with aging and neurodegenerative diseases. Zagociguat was safe and generally well tolerated in this 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 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 biomarker 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 across several endpoints with each other and with zagociguat plasma concentrations. Zagociguat was well tolerated with no 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 Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes ("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 demonstrate 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 movement on inflammatory biomarkers was 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 October 6, 2022, we announced that we had recently capped enrollment in our signal-seeking clinical study of zagociguat for the potential treatment of Alzheimer's disease with vascular pathology ("ADv")..Data from the ADv study are expected in the first half of 2023. The ADv study is supported in part by a $2 million grant from the Alzheimer’s Association’s Part the Cloud-Gates Partnership Grant Program (the "PTC Grant").

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.

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 the Akebia License Agreement (as defined below) 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 $225 million in pre-commercial milestones and total potential future development, regulatory, and commercialization milestone payments could result in up to $585 million. 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 continue to work to out-license olinciguat to an entity with strong cardiovascular and/or cardiopulmonary capabilities.

2021 Equity Private Placement

On June 3, 2021, the Company entered into a Common Stock Purchase Agreement (the “2021 Equity Private Placement”) for the private placement of 5,735,988 shares of the Company’s common stock, for total gross proceeds of approximately $18 million. The closing of the 2021 Equity Private Placement occurred on June 7, 2021. The Company did not utilize the services of a placement agent or broker and accordingly incurred no material related transaction fees or commissions.

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 to 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 for the year ended December 31, 2021. No shares of common stock have been issued or sold under the ATM Offering during the year ended December 31, 2022.

Basis of Presentation

The consolidated financial statements and the related disclosures have been prepared in accordance with U.S. generally accepted accounting principles. In the opinion of management, the 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 fiscal years presented.

The 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 consolidated financial statements.

Going Concern

At each reporting period, 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.

In accordance with Accounting Standards Codification ("ASC") 205-40, Going Concern, the Company evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. 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 has incurred recurring losses since its inception, including a net loss of $44.1 million for the year ended December 31, 2022. In addition, as of December 31, 2022, the Company had an accumulated deficit of $259.2 million. The Company expects to continue to generate operating losses for the foreseeable future. The

Company expects that its cash, cash equivalents and marketable securities as of December 31, 2022 will not be sufficient to fund operations for at least the next twelve months from the date of issuance of these consolidated financial statements and the Company will need to obtain additional funding. 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”.

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.

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 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 Accounting Policies

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Cyclerion Therapeutics, Inc. and its wholly owned subsidiaries, Cyclerion GmbH and Cyclerion Securities Corporation. All intercompany transactions and balances are eliminated in consolidation.

Segment Information

Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company's Chief Executive Officer who is the chief operating decision maker in

deciding how to allocate resources and in assessing performance. The Company currently operates in one reportable business segment - human therapeutics.

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.

Cash and Cash Equivalents

The Company considers all highly liquid investment instruments with a remaining maturity when purchased of three months or less to be cash equivalents. Investments qualifying as cash equivalents may consist of money market funds and overnight repurchase agreements. The carrying amount of cash equivalents approximates fair value.

Property and Equipment

Property and equipment, including leasehold improvements, are recorded at cost, and are depreciated when placed into service using the straight-line method based on their estimated useful lives as follows:


Asset Description		Estimated Useful Life (In Years)
Laboratory equipment		5
Computer and office equipment		3
Furniture and fixtures		7
Software		3

Software costs incurred during the preliminary project stage are expensed as incurred, while costs incurred during the application development stage are capitalized and amortized over the estimated useful life of the software. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable the expenditures will result in additional functionality. Maintenance and training costs related to software obtained for internal use are expensed as incurred.

Costs for capital assets not yet placed into service have been capitalized as construction in progress and are depreciated in accordance with the above guidelines once placed into service. Maintenance and repair costs are expensed as incurred.

Leasehold improvements are amortized over the shorter of the estimated useful life of the asset or the lease term.

Property and equipment that is no longer required for the business is considered disposed of when it ceases to be used. Disposals are either sold or retired and the net book value is removed from the consolidated balance sheet and a corresponding gain or loss on the sale or disposal is recognized as a component of operating expenses in the consolidated statements of operations and comprehensive loss.

Fair Value of Investment Instruments

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Level 2 — Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

Foreign Currency Translation Adjustment

The functional currency of the Company’s foreign subsidiary is its local currency, the Swiss franc. The assets and liabilities of the Company’s foreign subsidiary are translated into U.S. dollars at exchange rates in effect at the balance sheet date. Income and expense items are translated at the average exchange rates prevailing during the period. The cumulative translation effect for the Company’s foreign subsidiary is included as a foreign currency translation adjustment in the consolidated statements of stockholders’ equity and as a component of comprehensive loss in the consolidated statements of operations and comprehensive loss.

The Company’s intercompany accounts are typically denominated in the functional currency of the foreign subsidiary. Gains and losses resulting from the re-measurement of intercompany balances are recorded in the consolidated statements of operations.

Accounts Receivable

The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for receivables when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices. The Company’s receivables primarily relate to amounts earned under a development agreement with Ironwood, licensing agreement, and supply agreement. The Company believes that credit risks associated with these agreements are not significant. To date, the Company has not had significant write-offs of bad debt and the Company did not have an allowance for doubtful accounts as of December 31, 2022 or 2021.

Impairment of Long-Lived Assets

The Company regularly reviews the carrying amount of its long-lived assets to determine whether indicators of impairment may exist, which warrant adjustments to carrying values or estimated useful lives. If indications of impairment exist, projected future undiscounted cash flows associated with the asset are compared to the carrying amount to determine whether the asset’s value is recoverable. If the carrying value of the asset exceeds such projected undiscounted cash flows, the asset will be written down to its estimated fair value. There were no significant impairments of long-lived assets for the years ended December 31, 2022 or 2021.

Leases

Effective January 1, 2019, the Company adopted Accounting Standards Codification (“ASC”) Topic 842, Leases (“ASC 842”) using the optional transition method. The adoption of ASC 842 represents a change in accounting principle that aims to increase transparency and comparability among organizations by requiring the

recognition of right-of-use assets and lease liabilities on the balance sheet for both operating and finance leases. In addition, the standard requires enhanced disclosures that meet the objective of enabling financial statement users to assess the amount, timing, and uncertainty of cash flows arising from leases. The reported results for the years ended December 31, 2022 and 2021 reflect the application of ASC 842 guidance.

The recognition of right-of-use assets and lease liabilities related to the Company’s operating leases under ASC 842 has had a material impact on the Company’s consolidated financial statements.

As part of the ASC 842 adoption, the Company has used certain practical expedients outlined in the guidance. These practical expedients include:

•

Account policy election to use the short-term lease exception by asset class;

•

Election of the practical expedient package during transition, which includes:

•

An entity need not reassess whether any expired or existing contracts are or contain leases.

•

An entity need not reassess the classification for any expired or existing leases. As a result, all leases that were classified as operating leases in accordance with ASC 840 are classified as operating leases under ASC 842, and all leases that were classified as capital leases in accordance with ASC 840 are classified as finance leases under ASC 842.

•

An entity need not reassess initial direct costs for any existing leases.

The Company had a property lease for its headquarters location at 301 Binney Street, Cambridge, MA (the “Head Lease”). The Company determined if the arrangement was a lease at the inception of the contract. The asset component of the Company’s operating leases was recorded as operating lease right-of-use assets, and the liability component was recorded as current portion of operating lease liabilities and operating lease liabilities, net of current portion, in the Company’s consolidated balance sheets.

ROU assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at the commencement date. The Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments if an implicit rate of return is not provided with the lease contract. Operating lease right-of-use assets are adjusted for incentives received.

Lease cost was recognized on a straight-line basis over the lease term, and included amounts related to short-term leases. Variable lease costs that do not depend on an index or rate were recognized as incurred.

ROU assets and operating lease liabilities were remeasured upon certain modifications to leases using the present value of remaining lease payments and estimated incremental borrowing rate upon lease modification. The difference between the remeasured ROU assets and the operating lease liabilities were recognized as a gain or loss in operating expenses. The Company reviewed any changes to its lease agreements for potential modifications and/or indicators of impairment of the respective ROU asset.

On April 30, 2021, the Company entered into a Termination Agreement (the "Termination Agreement") for its Head Lease as initially amended on February 28, 2020, and further amended on September 15, 2020. Pursuant to the Termination Agreement, the Company surrendered the leased space of approximately 57,000 square feet to the building’s landlord. The Company did not pay any termination fees with the Termination Agreement. As a result of the termination of the Head Lease, the related right-of-use asset was written off, the lease liability was derecognized, and the $3.8 million security deposit was returned to the Company and recorded as part of our cash balance. In total, the Company recognized a loss on the termination of the Head Lease of $0.9 million for the year ended December 31, 2021. The loss is included in “General and administrative” expenses on our consolidated statement of operations and comprehensive loss.

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 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. Both the lease expense and services expense are recognized as a component of research and development costs in the consolidated statements of operations and comprehensive loss.

Paycheck Protection Program Loan

On April 21, 2020, the Company received loan proceeds in the amount of approximately $3.5 million pursuant to a promissory note agreement with a bank under the Paycheck Protection Program. The Paycheck Protection Program, established as part of the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”), provides for loans to qualifying businesses for amounts up to 2.5 times of the average monthly payroll expenses of the qualifying business. The Promissory Note had an original loan maturity of April 20, 2022, a stated interest rate of 1.0% per annum, and had payments of principal and interest that were due monthly after an initial six-month deferral period where interest accrued, but no payments were due. The Promissory Note provided for customary events of default, including, among others, those relating to failure to make payment when due and breaches of representations. The loan was subject to all the terms and conditions applicable under the PPP and was subject to review by the SBA for compliance with program requirements, including the Company’s certification that the economic uncertainty, at the time, made the PPP loan request necessary to support ongoing operations. On October 2, 2020, the SBA issued procedural guidance with respect to PPP loans and changes in ownership and the Company believes that it is compliant with respect to the 2020 Equity Private Placement and the ATM Offering.

In June 2020, the Payroll Protection Program Flexibility Act was signed into law adjusting certain key terms of loans issued under the PPP. In accordance with the PPPFA, the initial deferral period may be extended from six to up to ten months and the loan maturity may be extended from two to five years. The PPPFA also provided for certain other changes, including the extent to which the loan may be forgiven.

The loan’s principal and accrued interest were forgivable to the extent that the proceeds were used for eligible purposes, subject to certain limitations, and that the Company maintained its payroll levels over a twenty-four-week period following the loan date. The loan forgiveness amount may have been reduced if the Company terminated employees or reduced salaries during the twenty-four-week period. PPP loans are subject to audit and the SBA has indicated that companies that received over $2 million in proceeds should expect an audit. The Company believes that it has used the proceeds for eligible purposes consistent with the provisions of the PPPFA.

As the legal form of the Promissory Note is a debt obligation, the Company accounted for it as debt under Accounting Standards Codification (ASC) 470, Debt and recorded a short-term liability of $3.5 million in the consolidated balance sheets upon receipt of the loan proceeds. The Company accrued interest over the term of the loan and did not record additional interest at a market rate because the guidance on imputing interest in ASC 835-30, Interest excludes transactions where interest rates are prescribed by a government agency. Approximately $0.1 million of interest expense has been recognized within interest and other income, net in the consolidated statements of operations and comprehensive loss for the year ended December 31, 2021. In August 2021, the Company applied

with the SBA for forgiveness of the PPP loan and was notified on November 4, 2021 that the SBA has approved our application to forgive the entire amount of the loan and accrued interest. The Company recorded a gain on extinguishment of debt of $3.6 million in the December 31, 2021 consolidated statements of operations and comprehensive loss, representing the principal and accrued interest for the PPP Loan.

Revenue

Upon executing a revenue generating arrangement, the Company assesses whether it is probable the Company will collect consideration in exchange for the good or service it transfers to the customer. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”), it performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies the performance obligations. The Company must develop assumptions that require significant judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The assumptions that are used to determine the stand-alone selling price may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. The Company derives revenue from (1) license agreement and (2) supply agreement which are fully described in Note 13, License Agreement.

The Company generated revenue from a Development Agreement with Ironwood, pursuant to which the Company provided certain research and development services with respect to certain of Ironwood’s products and product candidates. Such research and development activities were governed by a joint steering committee composed of representatives of both companies. Services performed were invoiced at a mutually agreed upon rate and the initial term of the agreement was two years from the date of Separation and automatically renewed for one year unless either party notified the other at least six months prior to the expiration. Ironwood and the Company agreed that the Development Agreement would not be renewed beyond its initial term which ended on March 31, 2021.

The Company generates revenue from research and development grants under contracts with third parties that do not create customer-vendor relationships. The Company’s research and development grants are non-exchange transactions and are not within the scope of ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”). Contribution revenue earned from activities performed pursuant to research and development grants is reported as grant revenue in the Company’s consolidated statements of operations. Revenue from these grants is recognized as the Company incurs qualifying expenses as stipulated by the terms of the respective grant. Cash received from grants in advance of incurring qualifying expenses is recorded as deferred revenue. The Company records revenue and a corresponding receivable when qualifying costs are incurred before receiving payment from the grants.

Research and Development Costs

The Company expenses research and development costs to operations as incurred. The Company defers and capitalizes nonrefundable advance payments made by the Company for research and development activities until the related goods are received or the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company will adjust the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception.

Research and development expenses are comprised of costs incurred in performing research and development activities, which may include salary, benefits and other employee-related expenses; share-based compensation expense; laboratory supplies and other direct expenses; facilities expenses; overhead expenses; third-party contractual costs relating to nonclinical studies and clinical trial activities and related contract manufacturing expenses, development of manufacturing processes and regulatory registration of third-party manufacturing facilities; and other outside expenses.

General and Administrative Expenses

The Company expenses general and administrative costs to operations as incurred. General and administrative expense consists of compensation, share-based compensation, benefits and other employee-related expenses for personnel in the Company’s administrative, finance, legal, information technology, business development and human resource functions. Other costs include the legal costs of pursuing patent protection of the Company’s intellectual property, general and administrative related facility costs, insurance costs and professional fees for accounting and legal services.

Income taxes

The Company is primarily subject to U.S. federal and Massachusetts state income taxes. For federal and state income taxes, deferred tax assets and liabilities are recognized based upon temporary differences between the financial statement and the tax basis of assets and liabilities. Deferred income taxes are based upon prescribed rates and enacted laws applicable to periods in which differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, the Company provides a valuation allowance, if necessary, to reduce deferred tax assets to amounts that are realizable.

The tax positions taken or expected to be taken in the course of preparing the Company tax returns are required to be evaluated to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet a more-likely-than-not threshold would be recorded as a tax expense in the current year. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. It does not consider the likelihood of whether or not the IRS will review the position. Cyclerion evaluates uncertain tax positions on a quarterly basis and adjusts the level of the liability to reflect any subsequent changes in the relevant facts surrounding the uncertain positions. Any changes to these estimates, based on the actual results obtained and/or a change in assumptions, could affect Cyclerion's income tax provision in future periods. There were no uncertain tax positions that require accrual or disclosure in the consolidated financial statements as of December 31, 2022, and 2021. The Company’s policy is to recognize interest and penalties related to income tax, if any, in income tax expense. As of December 31, 2022, and 2021, the Company has no accruals for interest or penalties related to income tax matters.

Patent Costs

Patent fees and patent related costs in connection with filing and prosecuting patent applications are expensed as incurred and are classified as general and administrative expenses in the accompanying consolidated financial statements. The Company incurred and recorded as operating expense legal and other fees related to patents of approximately $1.7 million and $1.4 million for the years ended December 31, 2022 and 2021, respectively.

Interest and Other Income, Net

For the year ended December 31, 2022, interest and other income, net consisted of a $0.3 million of interest income related to interest generated from our cash and cash equivalents balances. For the year ended December 31, 2021, interest and other income, net consisted of a de minimis amount of interest income related to interest generated from our cash and cash equivalents balances and a de minimis amount of interest expense related to the PPP loan.

Subsequent Events

The Company considers events or transactions that have occurred after the balance sheet date of December 31, 2022, but prior to the filing of the financial statements with the Securities and Exchange Commission, to provide additional evidence relative to certain estimates or to identify matters that require additional recognition

or disclosure. Subsequent events have been evaluated through the filing of the financial statements accompanying this Annual Report on Form 10-K. See Note 15, Subsequent Events.

Recently Issued 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 years ended December 31, 2022 and 2021, that had a material effect on its 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 is currently evaluating the impact that ASU 2016-13 will have on its financial statements and related disclosures.

Recently Adopted Accounting Pronouncements

In May 2021 the FASB issued Accounting Standards Update No. 2021-04, Earnings Per Share ("Topic 260"), Debt-Modifications and Extinguishments ("Subtopic 470-50"), Compensation-Stock Compensation ("Topic 718"), and Derivatives and Hedging-Contracts in Entity’s Own Equity ("Subtopic 815-40"): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options, a consensus of the Emerging Issues Task Force ("EITF") , which amends the FASB Accounting Standards Codification ("ASC" or the “Codification”) to provide explicit guidance, and, thus, reduce diversity in practice, on accounting by issuers for modifications or exchanges of freestanding equity-classified written call options that remain equity classified after the modification or exchange. This amendment provides that for an entity that presents earnings per share ("EPS") in accordance with Topic 260, the effects of a modification or an exchange of a freestanding equity-classified written call option that is recognized as a dividend should be an adjustment to net income (or net loss) in the basic EPS calculation. The amended guidance effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years, and should be applied prospectively to modifications or exchanges occurring on or after the effective date. The Company adopted ASU 2021-04 in the first quarter of 2022, 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 consolidated financial statements upon adoption.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2022

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 December 31, 2022 and December 31, 2021 (in thousands):


	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


	Fair Value Measurements as of December 31, 2021:
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	52,917	$	—	$	—	$	52,917
Cash equivalents	$	52,917	$	—	$	—	$	52,917

During the year ended December 31, 2022 and 2021, 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, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of these amounts.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Property and Equipment

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Property and Equipment

4. Property and Equipment

Property and equipment, net consisted of the following (in thousands):


	December 31,			December 31,
	2022			2021
Software	$	2,174		$	2,214
Computer equipment		7			51
Property and equipment, gross		2,181			2,265
Less: accumulated depreciation and amortization		(2,181	)		(2,200	)
Property and equipment, net	$	—		$	65

As of December 31, 2022, and 2021, the Company’s property and equipment was primarily located in Boston, Massachusetts.

Depreciation and amortization expense of the Company’s property and equipment was approximately $0.1 million and $0.5 million for the years ended December 31, 2022 and 2021, respectively.

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2022

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):


	December 31,		December 31,
	2022		2021
Accrued incentive compensation	$	238	$	1,369
Salaries		246		266
Accrued vacation		186		345
Professional fees		835		398
Accrued severance and benefit costs		809		—
Other		68		526
Accrued expenses and other current liabilities	$	2,382	$	2,904

Commitments and Contingencies

12 Months Ended

Dec. 31, 2022

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 December 31, 2022 or December 31, 2021.

Leases

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Leases

. Leases

On April 30, 2021, the Company entered into a Termination Agreement (the "Termination Agreement") for its Head Lease (the "Head Lease") for the Company's former headquarters located at 301 Binney Street, Cambridge, MA, as initially amended on February 28, 2020, and further amended on September 15, 2020. Pursuant to the Termination Agreement, the Company surrendered the leased space of approximately 57,000 square feet to the building’s landlord. The Company did not pay any termination fees in connection with the Termination Agreement. As a result of the termination of the Head Lease, the related right-of-use asset was written off, the lease liability was derecognized, and the $3.8 million security deposit was returned to the Company and recorded as part of our cash balance.

Lease cost was recognized on a straight-line basis over the lease term. For the year ended December 31, 2021, the Company recognized approximately $2.4 million of total lease costs and $0.7 million of variable lease costs, related to the Head Lease. The Company did not record any lease costs related to the Head Lease during the year ended December 31, 2022.

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 $0.3 million and $0.1 million, respectively, in lease expense associated with the membership agreement during the years ended December 31, 2022, and 2021.

Supplemental cash flow information related to leases for the periods reported is as follows:


	Year Ended December 31,
	2022		2021
Decrease in right-of-use assets related to lease modifications and termination	$	—	$	42,058
Decrease in operating lease liabilities due to lease modifications and termination	$	—	$	41,177
Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$	—	$	1,887
Weighted-average remaining lease term of operating leases (in years)		—		—
Weighted-average discount rate of operating leases		—		—

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 $0.2 million and $0.1 million of lease expense during the years ended December 31, 2022 and 2021, 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 $0.4 million and 0.2 million for the years ended December 31, 2022 and 2021, respectively. Both the lease expense and services expense are recognized as a component of research and development costs in the consolidated statements of operations and comprehensive loss.

Share-based Compensation Plans

12 Months Ended

Dec. 31, 2022

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 also mirrored two of Ironwood Pharmaceuticals, Inc. ("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 Separation as part of the equity conversion. As a result of the Separation and in accordance with the EMA, 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 consolidated statements of operations and comprehensive loss for the years ended December 31, 2022 and 2021 (in thousands):


	Year Ended December 31,
	2022		2021
Research and development	$	2,915	$	3,945
General and administrative		3,337		5,666
	$	6,252	$	9,611

Stock Options

Stock options granted under the Company’s equity plans generally have a ten-year term and vest over a period of four years, provided the individual continues to serve at the Company through the vesting dates. Options granted under all equity plans are exercisable at a price per share not less than the fair market value of the underlying common stock on the date of grant. The estimated fair value of options, including the effect of estimated forfeitures, is recognized over the requisite service period, which is typically the vesting period of each option.

A summary of stock option activity for the year ended December 31, 2022 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, 2021		7,080,426	$	10.73		6.9		—
Granted		1,695,303		1.16
Exercised		—		—
Cancelled or forfeited		1,463,836		7.14
Outstanding as of December 31, 2022		7,311,893	$	9.23		5.8	$	20
Exercisable at December 31, 2022		5,282,088	$	11.88		4.8	$	—

During the years ended December 31, 2022 and 2021, the Company granted stock options to purchase an aggregate of 1,695,303 shares and 1,176,250 shares, respectively, at weighted average grant fair values per option share of $0.91 and $2.17 respectively. The total grant fair value of options granted during the years ended December 31, 2022 and 2021 was $1.5 million and $2.6 million, respectively.

The total intrinsic value of options exercised for the year ended December 31, 2021 was $0.1 million. There were no options exercised during the year ended December 31, 2022.

As of December 31, 2022, 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 $2.1 million and the weighted average period over which that expense is expected to be recognized is 3.3 years.

The weighted-average Black-Scholes assumptions used in estimating the fair value of the stock options granted by Cyclerion following the Separation during the years ended December 31, 2022 and 2021 were as follows:


	Year ended December 31,
	2022			2021
Weighted average risk-free interest rate		1.93	%		1.09	%
Expected dividend yield		—			—
Expected option term (in years)		6.0			5.9
Expected stock price volatility		98.90	%		85.45	%

For the years ended December 31, 2022 and 2021, expected volatility was estimated using an average of the historical volatility of the common stock of a group of similar companies that were publicly traded. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

The Company has granted to certain employees performance based options to purchase shares of common stock. These options are subject to performance based milestone vesting. During the year ended December 31, 2022, there were no shares that vested as a result of performance milestone achievements and 50,000 shares vested during the year ended December 31, 2021. The Company recorded a de minimis and no share-based compensation expense related to these performance-based options for the years ended December 31, 2022, and 2021, respectively.

Market-based Stock Options

The Company also 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. The Company does not reverse expense recognized if the share price target(s) are ultimately not achieved but expense is reversed when a stock award recipient has a break in service prior to the completion of the derived service period. As of December 31, 2022, 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 1.2 years.

A summary of stock awards containing market conditions activity for the years ended December 31, 2022 and 2021 is as follows:


						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Number of			Exercise		Contractual		Value (in
	Options			Price		Term (years)		thousands)
Outstanding as of December 31, 2021		450,000		$	2.01	$	7.9	$	—
Granted		—			—		—		—
Exercised		—			—		—		—
Cancelled or forfeited		(150,000	)	$	2.01	$	6.9	$	—
Outstanding as of December 31, 2022		300,000		$	2.01		6.9	$	—
Exercisable at December 31, 2022		—		$	—		—	$	—

The fair value of stock options containing market conditions is estimated using Monte Carlo simulations. No stock options containing market conditions were granted during the years ended December 31, 2022 and 2021.

Restricted Stock Units

The RSUs generally vest 25% per year on the approximate anniversary of the date of grant until fully vested, provided the employee remains continuously employed with the Company through each vesting date. Shares of the Company’s common stock are delivered to the employee upon vesting, subject to payment of applicable withholding taxes. The fair value of all RSUs is based on the market value of the Company’s common stock on the date of grant. Compensation expense, including the effect of estimated forfeitures, is recognized over the applicable service period.

A summary of RSU activity for the years ended December 31, 2022 is as follows:


				Weighted Average
	Number			Grant Date
	of Shares			Fair Value
Unvested as of December 31, 2021		92,804		$	13.70
Granted		800,000			0.53
Vested		(53,999	)		14.06
Forfeited		(23,218	)		13.43
Unvested as of December 31, 2022		815,587		$	0.77

As of December 31, 2022, the unrecognized share-based compensation expense, net of estimated forfeitures, related to all unvested restricted stock units by the Company’s employees is $0.4 million and the weighted-average period over which that expense is expected to be recognized is 0.8 years.

Loss per share

12 Months Ended

Dec. 31, 2022

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:


	Year Ended December 31,
	2022			2021
Numerator:
Net loss (in thousands)	$	(44,078	)	$	(51,647	)

Denominator:
Weighted average shares used in calculating net loss per share — basic and diluted (in thousands)		43,469			39,144
Net loss per share — basic and diluted	$	(1.01	)	$	(1.32	)

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 years ended December 31, 2022 and 2021:


	Year Ended December 31,
	2022		2021
Stock Options		7,611,893		7,530,426
RSUs		815,587		92,804
		8,427,480		7,623,230

Income Taxes

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

There was no provision for income taxes for the years ended December 31, 2022, and 2021, due to the Company’s operating losses and a full valuation allowance on deferred tax assets. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations follows (in thousands):


	Year Ended December 31,
	2022			2021
U.S.	$	(44,063	)	$	(51,686	)
International		(15	)		39
Loss before benefit from income taxes	$	(44,078	)	$	(51,647	)
Income tax benefit using U.S. federal statutory rate	$	(9,256	)	$	(10,846	)
State income taxes, net of federal benefit		(2,693	)		(3,631	)
Non-deductible share-based compensation		266			(911	)
Share-based compensation - shortfalls/(windfalls)		833			946
Permanent differences		14			(420	)
PPP loan forgiveness		—			(748	)
Tax credits		(1,652	)		(805	)
Other		3			(9	)
Change in valuation allowance		12,485			16,424
	$	—		$	—

The effective income tax rate is based upon the income for the year, the composition of the income in different countries, and adjustments, if any, for the potential tax consequences, benefits or resolutions of audits or other tax contingencies. Our income tax rate in foreign jurisdictions is lower than our income tax rate in the United States.

Deferred tax assets (liabilities) consist of the following as of December 31, 2022 and 2021 (in thousands):


	Year Ended December 31,
	2022			2021
Deferred tax assets:
Net operating loss carryforwards	$	47,079		$	43,700
Tax credit carryforwards		9,848			8,044
Share-based compensation		8,354			7,702
Operating lease - liability		—			—
Property and equipment		1			(1	)
Capitalized research and development		17,399			11,147
Accruals and reserves		340			91
Other		—			4
Total deferred tax assets	$	83,021		$	70,687

Deferred tax liabilities:
Operating lease - right of use asset	$	(333	)	$	(383	)
Prepaid sublease termination		(658	)		(758	)
Total deferred tax liabilities		(991	)		(1,141	)
Net deferred tax assets		82,030			69,546

Valuation allowance		(82,030	)		(69,546	)
Net deferred tax assets	$	—		$	—

Management has evaluated the positive and negative evidence bearing upon the possible realization of its deferred tax assets. Management has considered the Company's history of operating losses, in addition to the expected timing of the reversal of existing temporary differences and concluded, in accordance with the applicable accounting standards, that it is more likely than not that the Company will not realize the benefit of its deferred tax assets. Accordingly, the net deferred tax assets have been fully reserved at December 31, 2022 and December 31, 2021. Management reevaluates the positive and negative evidence on a quarterly basis.

The valuation allowance increased by approximately $12.5 million during the year ended December 31, 2022 primarily due to increases in capitalized research and development expenses, net operating losses, tax credit carryforwards and deferred tax assets related to share-based compensation.

The Company did not generate net operating loss carryforwards or tax credit carryforwards available for its use until its inception and operation as a standalone legal entity. At December 31, 2022 and 2021, Cyclerion has federal net operating loss carryforwards of approximately $172 million and $160 million, respectively, to offset future federal taxable income that will be carried forward indefinitely until utilized. As of December 31, 2022, and 2021, Cyclerion had state net operating loss carryforwards of approximately $173 million and $159.6 million, respectively, to offset future state taxable income, which will begin to expire in 2040 and will continue to expire through 2042. Cyclerion also had tax credit carryforwards of approximately $10.2 million and $8.4 million as of December 31, 2022 and 2021, respectively, to offset future federal and state income taxes. Federal credits begin to expire in 2040 and will continue to expire through 2041. State credits begin to expire in 2022 and continue through 2034.

The Company’s ability to use its operating loss carryforwards and tax credits to offset future taxable income could be subject to restrictions under Section 382 of the U.S. Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). These potential restrictions may limit the future use of the operating loss carryforwards and tax credits if certain ownership changes described in the Internal Revenue Code occur. Changes in stock ownership may occur that would create these limitations on the Company’s use of the operating loss carryforwards and tax credits. In such a situation, the Company may be required to pay income taxes, even though significant operating loss carryforwards and tax credits exist.

The Company has not as yet conducted a study of its research and development credit carry forwards. This study may result in an adjustment to the Company’s research and development credit carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s research and development credits, and if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the consolidated balance sheets or statements of operations if an adjustment were required.

Upon audit, taxing authorities may challenge all or part of an uncertain income tax position. While Cyclerion has no history of tax audits since its inception on a standalone basis, it may be subject to tax audits by federal and state taxing authorities in the future. Accordingly, Cyclerion regularly assesses the outcome of potential examinations in each of the taxing jurisdictions when determining the adequacy of the amount of unrecognized tax benefit recorded. Cyclerion had no unrecognized tax benefits as of December 31, 2022 and 2021. Cyclerion will recognize interest and penalties, if any, related to uncertain tax positions in income tax expense. As of December 31, 2022 and 2021, no interest or penalties have been accrued. There are no current federal or state income tax audits in progress.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Defined Contribution Plan

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

Defined Contribution Plan

11. Defined Contribution Plan

The Company has established a defined contribution 401(k) Savings Plan which allows eligible employees to contribute from 1% to 100% of their compensation, subject to certain IRS limits. 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 $0.2 million and $0.3 million related to the defined contribution 401(k) Savings Plan for the years ended December 31, 2022 and 2021, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Workforce Reduction

12 Months Ended

Dec. 31, 2022

Restructuring and Related Activities [Abstract]

Workforce Reduction

12. 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 were 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 year ended December 31, 2022 (in thousands):


	Amounts accrued at December 31, 2021		Charges			Amount paid		Amounts accrued at December 31, 2022
2022 workforce reduction	$	—	$	(1,327	)	$	518	$	(809	)
Total	$	—	$	(1,327	)	$	518	$	(809	)

License Agreements

12 Months Ended

Dec. 31, 2022

License Agreement [Abstract]

License Agreements

13. 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 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 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 $0.3 million and approximately $0.3 million, respectively, for the years ended December 31, 2022 and 2021, as revenue from the Supply Agreement.

Grant Revenue

12 Months Ended

Dec. 31, 2022

Disaggregation of Revenue [Line Items]

Grant Revenue

14. 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 is July 1, 2021, to December 31, 2022, and the Company will receive an award of up to $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 incurred approximately $1.3 million and approximately $0.6 million of allowable expenses and recognized a corresponding amount of grant revenue for the years ended December 31, 2022 and 2021.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI https://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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+ Details

Subsequent Events

12 Months Ended

Dec. 31, 2022

Subsequent Events [Abstract]

Subsequent Events

15. Subsequent Events

The Company has evaluated all events and transactions that occurred after the balance sheet date through the date the consolidated financial statements were issued and determined that there were no such events requiring recognition or disclosure in the consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Basis of Presentation

Principles of Consolidation

Segment Information

deciding how to allocate resources and in assessing performance. The Company currently operates in one reportable business segment - human therapeutics.

Use of Estimates

Cash and Cash Equivalents

Property and Equipment


Asset Description		Estimated Useful Life (In Years)
Laboratory equipment		5
Computer and office equipment		3
Furniture and fixtures		7
Software		3

Leasehold improvements are amortized over the shorter of the estimated useful life of the asset or the lease term.

Fair Value of Investment Instruments

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Foreign Currency Translation Adjustment

Accounts Receivable

Impairment of Long-Lived Assets

Leases

The recognition of right-of-use assets and lease liabilities related to the Company’s operating leases under ASC 842 has had a material impact on the Company’s consolidated financial statements.

As part of the ASC 842 adoption, the Company has used certain practical expedients outlined in the guidance. These practical expedients include:

•

Account policy election to use the short-term lease exception by asset class;

•

Election of the practical expedient package during transition, which includes:

•

An entity need not reassess whether any expired or existing contracts are or contain leases.

•

An entity need not reassess initial direct costs for any existing leases.

Paycheck Protection Program Loan

Revenue

Research and Development Costs

General and Administrative Expenses

Income taxes

Patent Costs

Interest and Other Income, Net

Subsequent Events

or disclosure. Subsequent events have been evaluated through the filing of the financial statements accompanying this Annual Report on Form 10-K. See Note 15, Subsequent Events.

Recently Issued/Adopted Accounting Pronouncements

Recently Issued Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Schedule of Estimated Useful Lives of Property and Equipment


Asset Description		Estimated Useful Life (In Years)
Laboratory equipment		5
Computer and office equipment		3
Furniture and fixtures		7
Software		3

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

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


	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


	Fair Value Measurements as of December 31, 2021:
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	52,917	$	—	$	—	$	52,917
Cash equivalents	$	52,917	$	—	$	—	$	52,917

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Schedule of property and equipment, net

Property and equipment, net consisted of the following (in thousands):


	December 31,			December 31,
	2022			2021
Software	$	2,174		$	2,214
Computer equipment		7			51
Property and equipment, gross		2,181			2,265
Less: accumulated depreciation and amortization		(2,181	)		(2,200	)
Property and equipment, net	$	—		$	65

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2022

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):


	December 31,		December 31,
	2022		2021
Accrued incentive compensation	$	238	$	1,369
Salaries		246		266
Accrued vacation		186		345
Professional fees		835		398
Accrued severance and benefit costs		809		—
Other		68		526
Accrued expenses and other current liabilities	$	2,382	$	2,904

Leases (Tables)

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Schedule of supplemental cash flow information related to leases

Supplemental cash flow information related to leases for the periods reported is as follows:


	Year Ended December 31,
	2022		2021
Decrease in right-of-use assets related to lease modifications and termination	$	—	$	42,058
Decrease in operating lease liabilities due to lease modifications and termination	$	—	$	41,177
Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$	—	$	1,887
Weighted-average remaining lease term of operating leases (in years)		—		—
Weighted-average discount rate of operating leases		—		—

Share-based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of share-based compensation expense


	Year Ended December 31,
	2022		2021
Research and development	$	2,915	$	3,945
General and administrative		3,337		5,666
	$	6,252	$	9,611

Schedule of stock option activity

A summary of stock option activity for the year ended December 31, 2022 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, 2021		7,080,426	$	10.73		6.9		—
Granted		1,695,303		1.16
Exercised		—		—
Cancelled or forfeited		1,463,836		7.14
Outstanding as of December 31, 2022		7,311,893	$	9.23		5.8	$	20
Exercisable at December 31, 2022		5,282,088	$	11.88		4.8	$	—

Schedule of weighted-average assumptions used in estimating the fair value of the stock options


	Year ended December 31,
	2022			2021
Weighted average risk-free interest rate		1.93	%		1.09	%
Expected dividend yield		—			—
Expected option term (in years)		6.0			5.9
Expected stock price volatility		98.90	%		85.45	%

Summary of stock awards containing market conditions activity

A summary of stock awards containing market conditions activity for the years ended December 31, 2022 and 2021 is as follows:


						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Number of			Exercise		Contractual		Value (in
	Options			Price		Term (years)		thousands)
Outstanding as of December 31, 2021		450,000		$	2.01	$	7.9	$	—
Granted		—			—		—		—
Exercised		—			—		—		—
Cancelled or forfeited		(150,000	)	$	2.01	$	6.9	$	—
Outstanding as of December 31, 2022		300,000		$	2.01		6.9	$	—
Exercisable at December 31, 2022		—		$	—		—	$	—

Schedule of weighted-average assumptions used in estimating the fair value of the stock awards containing market conditions

Summary of RSU activity

A summary of RSU activity for the years ended December 31, 2022 is as follows:


				Weighted Average
	Number			Grant Date
	of Shares			Fair Value
Unvested as of December 31, 2021		92,804		$	13.70
Granted		800,000			0.53
Vested		(53,999	)		14.06
Forfeited		(23,218	)		13.43
Unvested as of December 31, 2022		815,587		$	0.77

Loss per share (Tables)

12 Months Ended

Dec. 31, 2022

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:


	Year Ended December 31,
	2022			2021
Numerator:
Net loss (in thousands)	$	(44,078	)	$	(51,647	)

Denominator:
Weighted average shares used in calculating net loss per share — basic and diluted (in thousands)		43,469			39,144
Net loss per share — basic and diluted	$	(1.01	)	$	(1.32	)

Schedule Of Earnings Per Share Diluted By Common Class

The following table sets forth potential shares that were considered anti-dilutive for the years ended December 31, 2022 and 2021:


	Year Ended December 31,
	2022		2021
Stock Options		7,611,893		7,530,426
RSUs		815,587		92,804
		8,427,480		7,623,230

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Summary of reconciliation of income taxes computed using the U.S. federal statutory rate

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations follows (in thousands):


	Year Ended December 31,
	2022			2021
U.S.	$	(44,063	)	$	(51,686	)
International		(15	)		39
Loss before benefit from income taxes	$	(44,078	)	$	(51,647	)
Income tax benefit using U.S. federal statutory rate	$	(9,256	)	$	(10,846	)
State income taxes, net of federal benefit		(2,693	)		(3,631	)
Non-deductible share-based compensation		266			(911	)
Share-based compensation - shortfalls/(windfalls)		833			946
Permanent differences		14			(420	)
PPP loan forgiveness		—			(748	)
Tax credits		(1,652	)		(805	)
Other		3			(9	)
Change in valuation allowance		12,485			16,424
	$	—		$	—

Summary of deferred tax assets (liabilities)

Deferred tax assets (liabilities) consist of the following as of December 31, 2022 and 2021 (in thousands):


	Year Ended December 31,
	2022			2021
Deferred tax assets:
Net operating loss carryforwards	$	47,079		$	43,700
Tax credit carryforwards		9,848			8,044
Share-based compensation		8,354			7,702
Operating lease - liability		—			—
Property and equipment		1			(1	)
Capitalized research and development		17,399			11,147
Accruals and reserves		340			91
Other		—			4
Total deferred tax assets	$	83,021		$	70,687

Deferred tax liabilities:
Operating lease - right of use asset	$	(333	)	$	(383	)
Prepaid sublease termination		(658	)		(758	)
Total deferred tax liabilities		(991	)		(1,141	)
Net deferred tax assets		82,030			69,546

Valuation allowance		(82,030	)		(69,546	)
Net deferred tax assets	$	—		$	—

Workforce Reduction (Tables)

12 Months Ended

Dec. 31, 2022

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 year ended December 31, 2022 (in thousands):


	Amounts accrued at December 31, 2021		Charges			Amount paid		Amounts accrued at December 31, 2022
2022 workforce reduction	$	—	$	(1,327	)	$	518	$	(809	)
Total	$	—	$	(1,327	)	$	518	$	(809	)

Nature of Business (Details) $ / shares in Units, $ in Thousands							12 Months Ended		29 Months Ended
	May 29, 2023 TradingDay $ / shares	Nov. 29, 2022 TradingDay	Nov. 28, 2022 TradingDay	Jun. 01, 2022 TradingDay $ / shares	Jun. 03, 2021 USD ($) shares	Sep. 03, 2020 USD ($)	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) shares	Jul. 24, 2020 USD ($)	Nov. 15, 2019 Employee
Nature of Business
Health care trust fund, Description							recently capped enrollment in our signal-seeking clinical study of zagociguat for the potential treatment of Alzheimer's disease with vascular pathology ("ADv")..Data from the ADv study are expected in the first half of 2023. The ADv study is supported in part by a $2 million grant from the Alzheimer’s Association’s Part the Cloud-Gates Partnership Grant Program (the "PTC Grant").
Proceeds from equity private placement and ATM							$ 0	$ 30,503
Proceeds from 2020 Equity private placement and ATM							0	30,503
Common stock issued or sold under the ATM Offering							0
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				$ 1.00
Grace period \| TradingDay			180
Net loss							(44,078)	(51,647)	$ 44,100
Accumulated deficit							$ (259,154)	(215,076)	$ (259,154)
Issuance of common stock equity private placement and ATM								$ 30,503
Additional Grace Period \| TradingDay		180
Private Placement
Nature of Business
Issuance of common stock equity private placement and ATM (in shares) \| shares					5,735,988
Proceeds from equity private placement and ATM					$ 18,000
Proceeds from 2020 Equity private placement and ATM					$ 18,000
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		3,353,059
Cash commission of gross proceeds of sales of common stock, percentage						3.00%
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
Forecast [Member]
Nature of Business
Minimum bid price of its common stock \| $ / shares	$ 1.00
Minimum consecutive business days for which bid price must meet or exceed $1.00 per share to regain compliance \| TradingDay	10
Cyclerion Securities Corporation
Nature of Business
Pre commercial milestones and total potential future development							225,000
Commercialization milestone payments							$ 585,000
Number of employees \| Employee											0

Summary of Significant Accounting Policies - Segments and Cash (Details)	12 Months Ended
	Dec. 31, 2022 Segment
Segment Information
Number of reportable business segment	1

Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2022
Laboratory equipment
Property and Equipment
Estimated Useful Life (In Years)	5 years
Computer and office equipment
Property and Equipment
Estimated Useful Life (In Years)	3 years
Furniture and fixtures
Property and Equipment
Estimated Useful Life (In Years)	7 years
Software
Property and Equipment
Estimated Useful Life (In Years)	3 years

Summary of Significant Accounting Policies - Leases (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020	Apr. 30, 2021 USD ($) ft²	Sep. 15, 2020 USD ($) ft²
Leases
Election of practical expedients package				true
Rentable space terminated from lease agreement (in square feet) \| ft²						15,700
Loss on lease termination		$ 0	$ (881)
Sublease termination agreement estimated fair value of rooms		1,500				$ 1,500
Sublease termination agreement estimated fair value of services		2,900				$ 2,900
Prepaid rooms balance reclassified from other assets	$ 1,400	$ 1,400
Term of lease	8 years 10 months 17 days	8 years 10 months 17 days
Head Lease
Leases
Loss on lease termination			$ 900
Security Deposit Returned					$ 3,800
Sublease Termination Agreement
Leases
Rentable space terminated from lease agreement (in square feet) \| ft²					57,000
Rentable square feet terminated from sublease agreement \| ft²						15,700

Summary of Significant Accounting Policies - Paycheck Protection Program Loan (Details) - USD ($) $ in Thousands		12 Months Ended
	Apr. 21, 2020	Dec. 31, 2022	Dec. 31, 2021
Leases
Short-term liability		$ 3,500
Gain (Loss) on Extinguishment of Debt		$ 0	$ 3,564
PPP Loan
Leases
Proceeds from short-term note payable	$ 3,500
Interest Expense			$ 100

Summary of Significant Accounting Policies - Revenue, Patent Costs, and Interest and Other Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue
Development Agreement, initial term	2 years
Development Agreement, renewal period	1 year
Development Agreement, period for notification of cancellation	6 months
Interest and other income, net
Interest and other income, net
Interest income generated from cash and cash equivalents balances	$ 0.3
Patents
Patent Costs
Legal and other fees	$ 1.7	$ 1.4

Summary of Significant Accounting Policies - Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Income tax, penalties and interest accrued	$ 0	$ 0

Fair Value of Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Cash equivalents:
Total cash equivalents	$ 12,357	$ 52,917
Level 1
Cash equivalents:
Total cash equivalents	12,357	52,917
Money market funds
Cash equivalents:
Total cash equivalents	12,357	52,917
Money market funds \| Level 1
Cash equivalents:
Total cash equivalents	$ 12,357	$ 52,917

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property and Equipment
Property and equipment. gross	$ 2,181	$ 2,265
Less: accumulated depreciation and amortization	(2,181)	(2,200)
Property and equipment, net	0	65
Depreciation and amortization	65	472
Property and Equipment
Property and Equipment
Depreciation and amortization	100	500
Software
Property and Equipment
Property and equipment. gross	2,174	2,214
Computer and office equipment
Property and Equipment
Property and equipment. gross	$ 7	$ 51

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accrued Liabilities and Other Liabilities [Abstract]
Accrued incentive compensation	$ 238	$ 1,369
Salaries	246	266
Accrued vacation	186	345
Professional fees	835	398
Accrued severance and benefit costs	809	0
Other	68	526
Accrued expenses and other current liabilities	$ 2,382	$ 2,904

Leases - Summary (Details) $ in Millions	12 Months Ended
Leases - Summary (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Aug. 01, 2022	Sep. 30, 2021	May 31, 2021	Apr. 30, 2021 USD ($) ft²
Leases
Lessee, Operating Lease, Term of Contract	8 years 10 months 17 days			8 years 10 months 17 days
Licensed Room
Leases
lease expense	$ 0.2	$ 0.1
License and Service
Leases
lease expense	0.4	0.2
Head Lease
Leases
Security Deposit Returned						$ 3.8
Second Lease Amendment
Leases
Total lease costs	0.0	2.4
Variable lease costs	0.0	0.7
Termination Agreement
Leases
Surrendered Lease Space \| ft²						57,000
Security Deposit Returned						$ 3.8
WeWork
Leases
Lessee, Operating Lease, Term of Contract			12 months		12 months
Lessee, Operating Lease, Renewal Term			6 months
Total lease costs	$ 0.3	$ 0.1

Leases - Schedule of supplemental cash flow information related to leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Leases [Abstract]
Decrease in right-of-use assets related to lease modification and termination	$ 42,058
Decrease in operating lease liabilities due to lease modifications and termination	41,177
Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$ 1,887

Leases - Sublease as Lessor (Details) $ in Millions	3 Months Ended	12 Months Ended
Leases - Sublease as Lessor (Details) $ in Millions	Sep. 30, 2021 USD ($)	Dec. 31, 2022 USD ($)	Apr. 30, 2021 ft²	Sep. 15, 2020 USD ($) ft²
Sublease as lessor
Rentable space terminated from lease agreement (in square feet) \| ft²				15,700
Sublease termination agreement estimated fair value of rooms		$ 1.5		$ 1.5
Sublease termination agreement estimated fair value of services		2.9		$ 2.9
Prepaid rooms balance reclassified from other assets	$ 1.4	$ 1.4
Term of lease	8 years 10 months 17 days	8 years 10 months 17 days
Sublease Termination Agreement
Sublease as lessor
Rentable space terminated from lease agreement (in square feet) \| ft²			57,000

Share-based Compensation Plans (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) TradingDay $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Share-based Compensation Plans
Share-based compensation	$ 6,252	$ 9,611
Number of shares vested \| shares	0	50,000
Unrecognized share-based compensation expense	$ 100
Expected period to recognize the expense	1 year 2 months 12 days
Total intrinsic value	$ 0	$ 100
Granted (in shares) \| shares	0	0
Research and development
Share-based Compensation Plans
Share-based compensation	$ 2,915	$ 3,945
General and administrative
Share-based Compensation Plans
Share-based compensation	$ 3,337	5,666
Restricted Stock Units
Share-based Compensation Plans
Expected period to recognize the expense	9 months 18 days
Unrecognized share-based compensation expense	$ 400
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
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
Stock options
Share-based Compensation Plans
Share based compensation expense	$ 0	$ 0
Expected period to recognize the expense	3 years 3 months 18 days
Weighted average grant date fair value per option share \| $ / shares	$ 0.91	$ 2.17
Total grant date fair value of options granted	$ 1,500	$ 2,600
Unrecognized share-based compensation expense	$ 2,100
Granted (in shares) \| shares	1,695,303	1,176,250

Share-based Compensation Plans - Schedule of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 6,252	$ 9,611
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	2,915	3,945
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 3,337	$ 5,666

Share-based Compensation Plans - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Number of Options
Granted (in shares)	0	0
Stock options
Number of Options
Outstanding at beginning of the year (in shares)	7,080,426
Granted (in shares)	1,695,303	1,176,250
Exercised (in shares)	0
Cancelled or forfeited (in shares)	1,463,836
Outstanding at end of the year (in shares)	7,311,893	7,080,426
Exercisable (in shares)	5,282,088
Weighted Average Remaining Contractual Term (years)
Weighted Average Remaining Contractual Term, Outstanding (in years)	5 years 9 months 18 days	6 years 10 months 24 days
Weighted Average Remaining Contractual Term, Exercisable (in years)	4 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 20	$ 0
Aggregate Intrinsic Value, Exercisable	$ 0
Weighted Average Exercise Price
Outstanding at beginning of the year (in dollars per share)	$ 10.73
Granted (in dollars per share)	1.16
Exercised (in dollars per share)	0
Cancelled or forfeited (in dollars per share)	7.14
Outstanding at end of the year (in dollars per share)	9.23	$ 10.73
Exercisable (in dollars per share)	$ 11.88

Share-based Compensation Plans - Schedule of Weighted Average Assumptions used in estimating the fair value of the stock options (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Weighted average risk-free interest rate	1.93%	1.09%
Expected dividend yield	0.00%	0.00%
Expected option term (in years)	6 years	5 years 10 months 24 days
Expected stock price volatility	98.90%	85.45%

Share-based Compensation Plans - Stock Awards Containing Market Conditions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Number of Options
Granted (in shares)	0	0
Assumptions used to estimate fair value of performance-based stock options
Weighted average risk-free interest rate	1.93%	1.09%
Expected dividend yield	0.00%	0.00%
Expected stock price volatility	98.90%	85.45%
Performance stock options \| Minimum
Assumptions used to estimate fair value of performance-based stock options
Expected option term (in years)	4 years
Performance stock options \| Maximum
Assumptions used to estimate fair value of performance-based stock options
Expected option term (in years)	4 years 7 months 6 days
Stock options
Number of Options
Outstanding at beginning of the year (in shares)	7,080,426
Granted (in shares)	1,695,303	1,176,250
Exercised (in shares)	0
Cancelled or forfeited (in shares)	(1,463,836)
Outstanding at end of the year (in shares)	7,311,893	7,080,426
Exercisable (in shares)	5,282,088
Weighted-Average Exercise Price
Outstanding at beginning of the year (in dollars per share)	$ 10.73
Granted (in dollars per share)	1.16
Exercised (in dollars per share)	0
Cancelled or forfeited (in dollars per share)	7.14
Outstanding at end of the year (in dollars per share)	9.23	$ 10.73
Exercisable (in dollars per share)	$ 11.88
Weighted Average Remaining Contractual Term (years)
Weighted average remaining contractual term, outstanding at the end of period (in years)	5 years 9 months 18 days	6 years 10 months 24 days
Weighted Average Remaining Contractual Term, Exercisable (in years)	4 years 9 months 18 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 9 months 18 days	6 years 10 months 24 days
Aggregate intrinsic value, outstanding at the end of period	$ 20	$ 0
Aggregate intrinsic value, exercisable at the end of period	$ 0
Market-based Stock Options
Number of Options
Outstanding at beginning of the year (in shares)	450,000
Cancelled or forfeited (in shares)	(150,000)
Outstanding at end of the year (in shares)	300,000	450,000
Weighted-Average Exercise Price
Outstanding at beginning of the year (in dollars per share)	$ 2.01
Cancelled or forfeited (in dollars per share)	2.01
Outstanding at end of the year (in dollars per share)	$ 2.01	$ 2.01
Weighted Average Remaining Contractual Term (years)
Weighted average remaining contractual term, outstanding at the end of period (in years)	6 years 10 months 24 days
Weighted Average Remaining Contractual Term, Exercisable (in years)		7 years 10 months 24 days
Weighted Average Remaining Contractual Term, Cancelled or forfeited	6 years 10 months 24 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 10 months 24 days

Share-based Compensation Plans - Summary of RSU activity (Details)	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Number of Shares
Unvested the end of the period (in shares) \| shares	815,587
Weighted-Average Grant Date Fair Value
Expected period to recognize the expense	1 year 2 months 12 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
Number of Shares
Unvested at the beginning of the period (in shares) \| shares	92,804
Granted (in shares) \| shares	800,000
Vested (in shares) \| shares	(53,999)
Forfeited (in shares) \| shares	(23,218)
Unvested the end of the period (in shares) \| shares
Weighted-Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share) \| $ / shares	$ 13.70
Granted (in dollars per share) \| $ / shares	0.53
Vested (in dollars per share) \| $ / shares	14.06
Forfeited (in dollars per share) \| $ / shares	13.43
Unvested restricted common stock at the end of the period (in dollars per share) \| $ / shares	$ 0.77
Expected period to recognize the expense	9 months 18 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	$ 0.53

Loss per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended		29 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022
Numerator:
Net loss	$ (44,078)	$ (51,647)	$ 44,100
Denominator:
Weighted Average Number of Shares Outstanding, Basic	43,469	39,144
Weighted average shares used in calculating net loss per share - diluted	43,469	39,144
Net loss per share - basic	$ (1.01)	$ (1.32)
Net loss per share - diluted	$ (1.01)	$ (1.32)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-URI https://asc.fasb.org/extlink&oid=126732423&loc=SL123482106-238011

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=126958026&loc=d3e1448-109256

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Loss Per Share - Schedule Of Earnings Per Share Diluted By Common Class (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
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	$ 8,427,480	$ 7,623,230
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	7,611,893	7,530,426
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	$ 815,587	$ 92,804

Income Taxes - Additional disclosures (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes
Deferred tax assets, valuation allowance	$ 12,485,000	$ 16,424,000
Tax credit carryforwards	10,200,000	8,400,000
Provision for income tax	0	0
Unrecognized tax benefits	0	0
Accrued interest or penalties	0	0
Federal
Income Taxes
Net operating loss carryforwards	$ 172,000,000	160,000,000
Income tax credit expiration description	Federal credits begin to expire in 2040 and will continue to expire through 2041. State credits begin to expire in 2022 and continue through 2034
State
Income Taxes
Net operating loss carryforwards	$ 173,000,000	$ 159,600,000
Income tax credit expiration description	begin to expire in 2040 and will continue to expire through 2042

Income Taxes - Reconciliation of income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
U.S.	$ (44,063)	$ (51,686)
International	(15)	39
Loss before benefit from income taxes	(44,078)	(51,647)
Income tax benefit using U.S. federal statutory rate	(9,256)	(10,846)
State income taxes, net of federal benefit	(2,693)	(3,631)
Non-deductible share-based compensation	266	(911)
Share-based compensation - shortfalls/(windfalls)	833	946
Permanent differences	14	(420)
Tax credits	(1,652)	(805)
Other	3	(9)
Change in valuation allowance	12,485	16,424
Income Tax Expense (Benefit), Total	0	0
Paycheck Protection Program Loan [Member]
PPP loan forgiveness	$ 0	$ 748

Income Taxes - Deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryforwards	$ 47,079	$ 43,700
Tax credit carryforwards	9,848	8,044
Share-based compensation	8,354	7,702
Operating lease - liability	0	0
Property and equipment	1	(1)
Capitalized research and development	17,399	11,147
Accruals and reserves	340	91
other	0	4
Total deferred tax assets	83,021	70,687
Deferred tax liabilities:
Operating lease - right of use asset	(333)	(383)
Prepaid sublease termination	(658)	(758)
Total deferred tax liabilities	(991)	(1,141)
Net deferred tax assets	82,030	69,546
Valuation allowance	(82,030)	(69,546)
Net deferred tax assets	$ 0	$ 0

Defined Contribution Plan (Details) - USD ($)	12 Months Ended
Defined Contribution Plan (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan
401 (k) Savings Plan	us-gaap:QualifiedPlanMember
Matching contribution (as a percent of employee's contributions)	75.00%
Maximum amount of employer matching contribution	$ 6,000
Compensation expense related to the defined contribution 401(k) Savings Plan	$ 200,000	$ 300,000
Minimum
Defined Contribution Plan
Percent of compensation eligible employees may elect to contribute	1.00%
Maximum
Defined Contribution Plan
Percent of compensation eligible employees may elect to contribute	100.00%

Workforce Reduction (Details) $ in Thousands		12 Months Ended
Workforce Reduction (Details) $ in Thousands	Oct. 06, 2022 USD ($) Employees	Dec. 31, 2022 USD ($)
Restructuring Cost And Reserve [Line Items]
Charges		$ (1,327)
Amount paid		518
End of period		809
2020 Workforce Reduction
Restructuring Cost And Reserve [Line Items]
Beginning of period		0
2022 Workforce Reduction Plan
Restructuring Cost And Reserve [Line Items]
Charges		(1,327)
Amount paid		518
End of period		$ 809
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 Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 03, 2021	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues		$ 1,625	$ 3,942
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
Akbeia Supply Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues		$ 300	$ 300

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Grant Revenue (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended		18 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022
Revenue Recognition and Deferred Revenue [Abstract]
PTC Grant Award			$ 2.0
Allowable Expenses on Grant Revenue	$ 1.3	$ 0.6