Candel Therapeutics (CADL) 10-K28 Mar 242023 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2023	Mar. 21, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Registrant Name	CANDEL THERAPEUTICS, INC.
Entity Central Index Key	0001841387
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		29,347,468
Entity Public Float			$ 28.2
Entity File Number	001-40629
Entity Tax Identification Number	52-2214851
Entity Address, Address Line One	117 Kendrick St
Entity Address, Address Line Two	Suite 450
Entity Address, City or Town	Needham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02494
Entity Incorporation, State or Country Code	DE
City Area Code	617
Local Phone Number	916-5445
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	CADL
Security Exchange Name	NASDAQ
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for its 2024 Annual Meeting of Stockholders (the Proxy Statement) are incorporated by reference in Part III of this Annual Report on Form 10-K. Such Proxy Statement will be filed with the U.S. Securities and Exchange Commission within 120 days after the end of the fiscal year to which this report relates. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K
Auditor Name	KPMG LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 35,413	$ 70,058
Prepaid expenses and other current assets	1,384	1,887
Total current assets	36,797	71,945
Fixed assets, net	3,206	4,424
Lease right of use assets	816	1,056
Restricted cash	266	266
Other assets	116
Total assets	41,201	77,691
Current liabilities:
Accounts payable	422	380
Accrued expenses	4,356	4,723
Current portion of term loan payable to a bank	8,893
Current portion of lease liability	513	464
Other current liabilities		48
Total current liabilities	14,184	5,615
Deferred revenue		144
Term loan payable to a bank	11,632	20,202
Other long-term debt	751	648
Lease liability, net of current portion	973	1,486
Warrant liability	916	1,882
Total liabilities	28,456	29,977
Commitments and contingencies (Note 15)
Stockholders' equity
Preferred stock, $0.01 par value; 10,000,000 shares authorized at December 31, 2023 and 2022; no shares issued or outstanding at December 31, 2023 and 2022, respectively.
Common stock, $0.01 par value; 150,000,000 shares authorized at December 31, 2023 and 2022; 29,213,627 and 29,042,418 shares issued at December 31, 2023 and 2022, respectively; and 29,091,019 and 28,919,810 shares outstanding at December 31, 2023 and 2022, respectively.	290	290
Treasury stock (at cost)	(448)	(448)
Additional paid-in capital	149,931	146,961
Accumulated deficit	(137,028)	(99,089)
Total stockholders' equity	12,745	47,714
Total liabilities and stockholders' equity	$ 41,201	$ 77,691

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Preferred stock par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares, issued	29,213,627	29,042,418
Common stock, shares, outstanding	29,091,019	28,919,810

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Research and development service revenue, related party		$ 125
Operating expenses:
Research and development	$ 24,506	20,787
General and administrative	13,885	14,060
Total operating expenses	38,391	34,847
Loss from operations	(38,391)	(34,722)
Other income (expense):
Grant income		48
Interest income	2,081	1,218
Interest expense	(2,595)	(1,708)
Change in fair value of warrant liability	966	16,370
Total other income (expense), net	452	15,928
Net loss and comprehensive loss	$ (37,939)	$ (18,794)
Net loss per share - basic	$ (1.31)	$ (0.65)
Net loss per share - diluted	$ (1.31)	$ (0.65)
Weighted-average common shares outstanding, basic	28,935,289	28,823,480
Weighted-average common shares outstanding, diluted	28,935,289	28,823,480

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock Member	Additional Paid In Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 64,137	$ 286		$ 144,146	$ (80,295)
Beginning Balance, Shares at Dec. 31, 2021		28,689,842
Options exercised	512	$ 4		508
Options exercised, Shares		352,576
Treasury stock acquired	(448)		$ (448)
Treasury stock acquired, Shares			(122,608)
Stock-based compensation	3,145			3,145
Change in fair value of NC Ohio Trust Warrants	(838)			(838)
Net loss	(18,794)				(18,794)
Ending Balance at Dec. 31, 2022	$ 47,714	$ 290	$ (448)	146,961	(99,089)
Ending Balance, Shares at Dec. 31, 2022	28,919,810	29,042,418	(122,608)
Stock-based compensation	$ 3,137			3,137
Restricted stock unit vesting, net of shares withheld for taxes	(121)			(121)
Restricted stock unit vesting, net of shares withheld for taxes, Shares		171,209
Change in fair value of NC Ohio Trust Warrants	(46)			(46)
Net loss	(37,939)				(37,939)
Ending Balance at Dec. 31, 2023	$ 12,745	$ 290	$ (448)	$ 149,931	$ (137,028)
Ending Balance, Shares at Dec. 31, 2023	29,091,019	29,213,627	(122,608)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash Flows from Operating Activities:
Net loss	$ (37,939)	$ (18,794)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	960	778
Impairment of fixed assets	390
Loss on the sale of fixed assets	79
Non-cash stock compensation expense	3,091	2,307
Non-cash lease expense	240	209
Non-cash interest expense	103	89
Change in fair value of warrant liability	(966)	(16,370)
Accretion of debt discount	323	291
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	503	416
Other assets	(116)
Accounts payable	45	(1,213)
Accrued expenses	(301)	1,265
Deferred revenue	(192)	67
Lease liability	(464)	(464)
Net cash used in operating activities	(34,244)	(31,419)
Cash Flows from Investing Activities:
Purchase of fixed assets	(457)	(1,297)
Proceeds from the sale of fixed assets	177
Net cash used in investing activities	(280)	(1,297)
Cash Flows from Financing Activities:
Net proceeds from bank term loan		19,910
Payments related to tax withholding for vested restricted stock units	(121)
Proceeds from option exercises		64
Net cash (used in) provided by financing activities	(121)	19,974
Net decrease in cash	(34,645)	(12,742)
Cash, cash equivalents and restricted cash at beginning of period	70,324	83,066
Cash, cash equivalents and restricted cash at end of period	35,679	70,324
Supplemental cash flow information:
Cash paid for taxes		183
Cash paid for interest	$ 2,148	1,152
Supplemental disclosures of non-cash information:
Lease liability arising from obtaining right-of-use assets		2,368
Capital expenditures in accounts payable and accrued expenses		69
Common stock exchange for option exercise		$ 448

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (37,939)	$ (18,794)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b51 Arr Modified Flag	false
Non Rule 10b51 Arr Modified Flag	false

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
Organization and Basis of Presentation	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Candel Therapeutics, Inc., formerly known as Advantagene, Inc. (the Company), is a clinical stage biopharmaceutical company that was incorporated in Delaware in June 2003. On November 30, 2020, the Company changed its name to Candel Therapeutics, Inc. The Company is focused on developing off-the-shelf viral immunotherapies that elicit an individualized, systemic anti-tumor immune response to help patients fight cancer. The Company’s engineered viruses are designed to induce immunogenic cell death through direct viral-mediated cytotoxicity in cancer cells, thus releasing tumor neo-antigens and creating a pro-inflammatory microenvironment at the site of injection. This is intended to lead to in-situ vaccination against the injected tumor and uninjected distant metastases. The Company has established two off-the-shelf viral immunotherapy platforms and its two product candidates, CAN-2409 and CAN-3110, are in clinical trials for a number of tumor types. Additionally, the Company and the University of Pennsylvania (UPenn) are collaborating to study the impact of novel viral immunotherapies based on Candel's propriety enLIGHTEN Discovery Platform, a systematic, iterative herpes simplex virus based platform leveraging human biology and advanced analytics, to strengthen the effects of UPenn's investigational CAR-T cell therapies in solid tumors. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales. Since inception, the Company has funded its operations primarily with proceeds from the sale of its convertible notes and capital stock and from debt borrowings. The Company has incurred recurring losses since its inception, including a net loss of $ 37.9 million and $ 18.8 million for the years ended December 31, 2023, and 2022, respectively. In addition, as of December 31, 2023, the Company had an accumulated deficit of $ 137.0 million . The Company expects to continue to generate operating losses and negative cash flows from operations for the foreseeable future. On August 5, 2022, the Company filed a shelf registration statement on Form S-3 (as amended to date, the Shelf) with the SEC, which covers the offering, issuance, and sale by us of up to an aggregate of $ 200.0 million of our common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. We simultaneously entered into a sales agreement with Jefferies LLC, as sales agent, to provide for the issuance and sale by us of up to $ 75.0 million of our common stock from time to time in “at-the-market” offerings under the Shelf (the ATM Program). The Shelf was declared effective by the SEC on August 12, 2022. Subsequent to December 31, 2023 and through March 21, 2024, we have sold and issued 109,485 shares of common stock under the ATM Program, with total net proceeds of $ 0.2 million . The Company’s cash and cash equivalents were $ 35.4 million as of December 31, 2023. In accordance with the Financial Accounting Standards Board (FASB) Accounting Standards Codification, 205-40, Presentation of Financial Statements - Going Concern, management is required to assess the Company’s ability to continue as a going concern for the one-year look forward period following the date that the consolidated financial statements are issued. The Company's expects to continue to generate operating losses and negative cash flows from operations. Based on these conditions, the Company has determined that substantial doubt exists regarding its ability to continue as a going concern for the one-year period following the date these consolidated financial statements are issued. To sustain its future operations beyond such one-year period, the Company will require additional funding. The Company expects to finance its cash needs through a combination of public or private equity or debt financings, government grants, and other sources, which may include collaborations, strategic alliances and licensing arrangements with third parties. There is no assurance that the Company will be successful in obtaining sufficient funding on acceptable terms, if at all, and the Company could be forced to delay, reduce, or eliminate some or all of its research, clinical trials, product development or future commercialization efforts, which could materially adversely affect its business prospects or its ability to continue as a going concern. The consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and that contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting standards set by the Financial Accounting Standards Board (FASB). The FASB sets generally accepted accounting principles (GAAP) that the Company follows to ensure its financial condition, results of operations, and cash flows are consistently reported. References to GAAP issued by the FASB in these notes to the financial statements are to the FASB Accounting Standards Codification (ASC). The Company has reclassified certain amounts relating to its prior period results to conform to its current period presentation. Principles of Consolidation The consolidated financial statements include the accounts of Candel Therapeutics, Inc. and its wholly owned subsidiary Candel Therapeutics Securities Corporation. All intercompany transactions and balances have been eliminated. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company and the Company's chief operating decision maker, the Company's chief executive officer, views the Company's operations and manages its business as a single operating segment. The Company only operates in the United States. Emerging Growth Company The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the Jobs Act). Under the Jobs Act emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the Jobs Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the Jobs Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company’s management evaluates its estimates, which include but are not limited to management’s judgments of accrued expenses, valuation of stock-based option awards, valuations of warrants, and income taxes. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original final maturities of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents comprise marketable securities with maturities of less than three months when purchased. Cash equivalents are reported at fair value. Restricted Cash The Company had $ 0.3 million of restricted cash as of both December 31, 2023 and 2022 , which represents cash held as a security deposit under the terms of the Company’s Needham, Massachusetts facility lease. Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. 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 that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The carrying values of cash and cash equivalents (considered as Level 1 measurements), accounts payable, and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities. The carrying value of the Company's term loan approximates fair value due to the variable interest rate. The Company’s warrant liability is carried at fair value and is classified as Level 3 measurement. Property and Equipment Property and equipment consist of laboratory and manufacturing equipment, networking and computer equipment, furniture and fixtures and leasehold improvements. Property and equipment are recorded at cost, and depreciated using the straight-line method over the estimated useful lives of the respective assets: ASSET ESTIMATED USEFUL LIFE Networking and computer equipment 5 years Laboratory equipment 5 years Manufacturing equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of the useful life or remaining lease term Leases The Company adopted ASC 842 as of January 1, 2022 and elected the transition method under ASU 2016-02 whereby the Company records a right-of-use asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. The Company also elected to apply the practical expedients intended to ease transition. Accordingly, the Company has only applied ASC 842 to leases existing as of January 1, 2022. The Company determines if an arrangement is, or contains, a lease at inception. Lease right of use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Lease right of use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments to be made over the lease term. The lease right of use asset is equal to the lease liability and adjusted for prepaid rent, initial direct costs, and incentives. As the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term. The Company has elected to not apply the recognition requirements of ASC 842 for short-term leases, which is defined as a lease that, at the lease commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the Company is reasonably certain to exercise. For real estate lease agreements entered into or modified after the adoption of ASC 842 that include lease and non-lease components, the Company has elected to account for the lease and non-lease components, such as common area maintenance charges, as a single lease component term. Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Periodically, the Company maintains deposits in accredited financial institutions in-excess of the federally insured limits. The Company deposits its cash in financial institutions with a high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal risk associated with commercial banking relationships. Impairment of Long-lived Assets Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. Long-lived assets consist of fixed assets and operating lease assets. In the third and fourth quarters of 2023, the Company recorded impairment charges totaling approximately $ 0.4 million related to manufacturing equipment that the Company has determined it does not plan to use for its intended use, and the Company recorded an impairment to reduce the carrying value to its estimated fair value. The Company has not recorded any other impairment losses on such long-lived assets. Revenue Recognition The Company applies Accounting Standards Codification (ASC), Topic 606, Revenue from Contracts with Customers, (ASC 606). This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity 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 entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and then assesses whether or not each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Research and Development Costs and Accruals Research and development expenses include salaries and benefits, materials and supplies, preclinical and clinical trial expenses, stock-based compensation expense, depreciation of equipment, contract services and other outside expenses. The Company has entered into various research and development-related contracts with clinical and research institutions, contract research organizations, and other companies. These agreements are generally cancelable, and related payments are recorded as research and development expenses as incurred. Costs of certain development activities, such as manufacturing, pre-clinical and clinical trial expenses, are recognized based on an evaluation of the progress to completion of specific tasks. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid or accrued research and development costs. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. Costs incurred in obtaining technology licenses and intellectual property are charged to research and development expenses as acquired in-process research and development if the technology licensed or intellectual property acquired has not reached technological feasibility and has no alternative future use. Patent Costs All patent-related costs incurred in connection with preparing, filing, maintaining and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified in general and administrative expenses. Stock-Based Compensation The Company accounts for its stock-based compensation in accordance with ASC Topic 718, Compensation—Stock Compensation (ASC 718). ASC 718 requires all share-based payments to employees and directors to be recognized as expense in the consolidated statements of operations based on their grant date fair values. In addition, in accordance with FASB Accounting Standards Update (ASU) 2016-09 which identifies areas for simplification of several areas of share-based payment transactions, the Company treats non-employee grants the same as employee grants. The Company estimates the fair value of options granted using the Black-Scholes option pricing model for stock option grants to both employees and non-employees. The Company believes the fair value of the stock options granted to non-employees is more reliably determinable than the fair value of the services provided. The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate and (d) expected dividends. Due to a lack of company-specific historical and implied volatility data, the Company has based its computation of expected volatility on a combination of the historical volatility of the Company and of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus. The historical volatility is calculated based on a period of time commensurate with the expected term assumption. The Company uses the simplified method as prescribed by the SEC Staff Accounting Bulletin No. 107, Share-Based Payment, to calculate the expected term for options granted to employees as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The expected term is applied to the stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among its employee population. For options granted to non-employees, the Company utilizes the contractual term of the share-based payment as the basis for the expected term assumption. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company generally expenses the fair value of its share-based compensation awards to employees and non-employees on a straight-line basis over the requisite service period, which is generally the vesting period. Government Grants The Company has applied for grants for the reimbursement of expenditures with the Massachusetts Life Sciences Center for certain qualified operating expenditures, including employee related costs. The Company recognizes government grants when there is reasonable assurance that the Company will comply with the conditions attached to the grant arrangement and the grant will be received. Government grants are recorded as grant income and classified in other income in the consolidated statements of operations. The Company recognized government grants of zero and $ 48,000 for the years ended December 31, 2023 and 2022 , respectively. Grant income is recognized as a component of other income/(expense), net in the consolidated statements of operations. Income Taxes The Company accounts for income taxes using the asset and liability method in accordance with ASC Topic 740, Income Taxes (ASC 740) which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. At December 31, 2023 and 2022, the Company has concluded that a full valuation allowance is necessary for its deferred tax assets (see Note 12). The Company accounts for uncertainty in income taxes, by applying the two-step process to determine the amount of tax benefit to be recognized in the financial statements. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax is then assessed as the amount of benefits to be recognized in the consolidated financial statements. The amount of benefits that may be used are the largest amounts that have a greater than 50 % likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves or unrecognized tax benefits that are considered appropriate as well as the related net interest received. Net Loss Per Share Basic net loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period and, if dilutive, the weighted-average number of potential shares of common stock. In periods where the Company reports a net loss attributable to common stockholders, diluted net loss per share is the same as basic net loss per share, since dilutive shares of common stock are not assumed to have been issued if their effect is anti-dilutive. Diluted net loss per share is the same as basic net loss per share for the years ended December 31, 2023 and 2022 since all potential shares of common stock instruments are anti-dilutive as a result of the loss for such periods. Recently Issued Accounting Standards In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC's Disclosure Update and Simplification Initiative, which modifies the disclosure or presentation requirements related to a variety of FASB Accounting Standard Codification topics. The effective date for each amendment will be the date on which the SEC's removal of that related disclosure from Regulation S-X or Regulation S-K is effective, with early adoption prohibited. If by June 30, 2027, the SEC has not removed the applicable requirement from Regulation S-X or Regulation S-K, the pending content of the associated amendment will be removed from the Codification and will not become effective for any entities. The Company is currently evaluating the potential impact that ASU 2023-06 may have on its consolidated financial statements and related disclosures. In November 2023, the FASB issued ASU 2023-07, Segment Reporting: Improvements to Reportable Segment Disclosures, which amends guidance in ASC 280, Segment Reporting The amendments in this ASU expand segment disclosure requirements, including new segment disclosure requirements for entities with a single reportable segment, among other disclosure requirements. The ASU’s amendments are effective for public business entities for annual periods beginning after December 15, 2023. Early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of ASU 2023-07 may have have on its consolidated financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures, which amends the guidance in ASC 740, Income Taxes. The ASU is intended to improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. The ASU’s amendments are effective for public business entities for annual periods beginning after December 15, 2024. Early adoption is permitted. Adoption can be either prospectively or retrospectively applied, and the Company will adopt this ASU on a prospective basis. The Company is currently evaluating the potential impact that ASU 2023-09 may have on its consolidated financial statements and related disclosures.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	12 Months Ended
Fair Value of Financial Assets and Liabilities	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	3. Fair Value of Financial Assets and Liabilities The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): FAIR VALUE MEASUREMENTS AS OF LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Liabilities: Warrant liability — — 916 916 Total $ — $ — $ 916 $ 916 FAIR VALUE MEASUREMENTS AS OF LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Liabilities: Warrant liability — — 1,882 1,882 Total $ — $ — $ 1,882 $ 1,882 Valuation of Warrant Liability In connection with the November 13, 2018 issuance of Series B convertible preferred stock, the Company issued warrants to purchase shares of common stock of which certain warrants are shown as a liability on the balance sheet, see Note 10. The fair value of the warrant liability was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The fair value of the warrant liability uses various valuation methods, including the Monte Carlo method, the option-pricing method, probability-weighted expected return and the hybrid method, all of which incorporate assumptions and estimates, to value the common stock warrants. The hybrid method is often used when a company is expecting a liquidity event in the near future and is a combination of the option-pricing and probability-weighted expected return methods. Estimates and assumptions impacting the fair value measurement include the fair value per share of the underlying shares of common stock, risk-free interest rate, expected dividend yield, expected volatility of the price of the underlying common stock, and the remaining contractual term of the warrants. The most significant assumption in the model impacting the fair value of the common stock warrants is the fair value of the Company’s common stock as of each remeasurement date. The following table provides a roll forward of the aggregate fair values of the Company’s warrant liability, for which fair value is determined by Level 3 inputs (in thousands): SERIES B Balance at December 31, 2021 $ 18,252 Change in fair value ( 16,370 ) Balance at December 31, 2022 $ 1,882 Change in fair value ( 966 ) Balance at December 31, 2023 $ 916

Fixed Assets, Net

Fixed Assets, Net	12 Months Ended
Fixed Assets, Net	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Fixed Assets, Net	4. Fixed Assets, Net Fixed assets, net consisted of the following (in thousands): DECEMBER 31, 2023 2022 Laboratory equipment $ 1,209 $ 1,055 Manufacturing equipment 730 1,201 Furniture and fixtures 159 159 Networking and computer equipment 88 81 Leasehold improvements 3,109 3,057 Total fixed assets $ 5,295 $ 5,553 Less: accumulated depreciation ( 2,089 ) ( 1,129 ) Fixed assets, net $ 3,206 $ 4,424 Depreciation expense was $ 1.0 million and $ 0.8 million for the years ended December 31, 2023 and 2022 , respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
Accrued Expenses	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): DECEMBER 31, 2023 2022 Payroll and employee related expenses $ 2,017 $ 2,647 Third-party research and development expenses 1,811 1,486 Professional fees and other 528 590 $ 4,356 $ 4,723

Term Loan

Term Loan	12 Months Ended
Term Loan	Dec. 31, 2023
Debt Disclosure [Abstract]
Term Loan	6. Term Loan On February 24, 2022 , the Company entered into a four-year loan and security agreement (the Loan Agreement) with Silicon Valley Bank (SVB) pursuant to which SVB has agreed to provide term loans to the Company in an aggregate principal amount of up to $ 25.0 million. The Company borrowed $ 20.0 million upon entering into the Loan Agreement. The Company could have borrowed up to an additional aggregate principal amount not to exceed $ 5.0 million, at any time on or prior to December 31, 2022, upon achievement of all of the following milestones, inclusively: (a) positive phase 2 clinical activity data from the Company’s CAN-2409 NSCLC clinical trial, (b) dosing of its first patient in its phase 3 CAN-2409 high-grade glioma clinical trial, and (c) receipt on or prior to December 31, 2022, of net cash proceeds in an amount equal to at least $ 75.0 million from the issuance and sale of equity securities to investors acceptable to SVB. The Company did not borrow any of the additional aggregate principal amount on or prior to December 31, 2022. The term loan is secured by substantially all of the Company’s properties, rights and assets, except for its intellectual property, which is subject to a negative pledge under the Loan Agreement. The term loans bear interest at a floating rate per annum equal to the greater of (A) 5.75 % and (B) the prime rate (as published in the money rates section of The Wall Street Journal) plus 2.50 %. The Company is required to make monthly interest payments, and commencing on February 1, 2024 , 24 consecutive installments of principal plus monthly payments of accrued interest. The term loans mature on January 1, 2026 . Upon repayment in full of the term loans, the Company will be required to pay a final payment fee equal to 4.50 % of the original principal amount of any funded term loan being repaid. The Loan Agreement permits voluntary prepayment of all, but not less than all, of the SVB term loans, subject to a prepayment premium of 1 % to 3 % based upon the timing of the repayment. During the years ended December 31, 2023 and 2022, the Company recorded interest expense relating to the Loan Agreement of $ 2.5 million and $ 1.6 million , respectively. The weighted average effective interest rate as of December 31, 2023 was 11.19 %. The Company incurred $ 89,000 of debt issuance costs and will incur a $ 0.9 million final payment fee, which were recorded as debt discount and are being amortized over the term of the Loan Agreement. The scheduled principal payments and net carrying amount of the term loan are as follows (in thousands): YEAR ENDING DECEMBER 31, 2024 $ 9,167 2025 10,000 2026 833 Total principal 20,000 Final payment fee 900 Less: debt discount ( 989 ) Accretion of debt discount 614 Net carrying amount $ 20,525 Less current portion $ ( 8,893 ) Long-term portion $ 11,632 The carrying value of the Company's term loan approximates fair value.

Other Long-Term Debt

Other Long-Term Debt	12 Months Ended
Other Long-Term Debt	Dec. 31, 2023
Debt Disclosure [Abstract]
Other Long-Term Debt	7. Other Long-Term Debt Periphagen Note On December 9, 2019, the Company entered into a series of asset purchase agreements with Periphagen, Inc. (Periphagen), a biopharmaceutical company focused on the development of gene therapy vectors. Under the terms of the asset purchase agreements, the Company assumed a $ 1.0 million promissory note bearing a contractual interest rate of 2 % compounded annually, with the outstanding balance and accrued interest due upon maturity in November 2027 , with no interim installments due. The estimated market rate for the Company for an unsecured loan with a maturity in November 2027 was determined to be 15.83 % as of December 9, 2019. Although the Company does not have a public credit rating, management estimates a CCC credit rating based on the Company’s financial position and stage of development. Using the commensurate rate for a CCC rated company and based on the amount due at maturity, the present value of the future cash outflow was determined to be $ 0.4 million at the transaction date. As of December 31, 2023, the carrying value of the note is $ 0.8 million . The carrying value of the note approximates fair value. Upon maturity, the Company will pay Periphagen $ 1.4 million for the outstanding balance and accrued interest due.

Lease

Lease	12 Months Ended
Lease	Dec. 31, 2023
Leases [Abstract]
Lease	8. Lease On February 4, 2019, the Company signed a lease agreement for its corporate headquarters at 117 Kendrick Street in Needham, Massachusetts. The facility consists of a 15,197 square foot property which houses the corporate, clinical, laboratory and manufacturing operations for the Company. The lease term ends on August 31, 2026 . For each of the years ended December 31, 2023 and 2022, the Company recorded $ 0.4 million of operating lease cost and $ 0.1 million of variable lease cost. The total lease expense for each of the years ended December 31, 2023 and 2022 was $ 0.5 million . Cash paid for amounts included in the lease liability for each of the years ended December 31, 2023 and 2022 was $ 0.6 million . YEAR ENDED DECEMBER 31, Other Information 2023 2022 Operating cash flows used for operating leases (in thousands) $ 583 $ 567 Weighted-average remaining lease term (years) 2.7 3.7 Weighted-average incremental borrowing rate 7.02 % 7.02 % The future lease payments under non-cancelable leases at December 31, 2023, are as follows (in thousands): 2024 598 2025 613 2026 415 Total future lease payments 1,626 Less: imputed interest ( 140 ) Total lease liability $ 1,486

Common Stock and Preferred Stoc

Common Stock and Preferred Stock	12 Months Ended
Common Stock and Preferred Stock	Dec. 31, 2023
Equity [Abstract]
Common Stock and Preferred Stock	9. Common Stock and Preferred Stock Preferred Stock The Company has authorized 10,000,000 shares of $ 0.01 par value preferred stock at December 31, 2023 and 2022. Common Stock The Company has authorized 150,000,000 shares of $ 0.01 par value common stock at December 31, 2023 and 2022 of which 29,213,627 and 29,042,418 were issued as of December 31, 2023 and 2022, respectively. The Company had 29,091,019 and 28,919,810 outstanding shares as of December 31, 2023 and 2022, respectively. Common shares are voting and dividends may be paid when, as and if declared by the board of directors. Common Stock Reserved The Company has reserved the following shares of common stock for future issuance as of: DECEMBER 31, 2023 2022 Stock options outstanding 5,666,621 5,645,420 Unvested restricted stock 2,526,432 612,366 Shares available for future grant under stock option plan 252,053 1,311,915 Warrants 7,507,708 7,507,708 15,952,814 15,077,409 Shelf Registration and At-the-Market Offerings On August 5, 2022, the Company filed the Shelf with the SEC, which covers the offering, issuance, and sale by us of up to an aggregate of $ 200.0 million of our common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. We simultaneously entered into a sales agreement with Jefferies LLC, as sales agent, to provide for the issuance and sale by us of up to $ 75.0 million of our common stock from time to time in “at-the-market” offerings under the Shelf. The Shelf was declared effective by the SEC on August 12, 202 2. Due to the SEC’s “baby shelf rules,” which prohibit companies with a public float of less than $ 75.0 million from issuing securities under a shelf registration statement in excess of one third of such company’s public float in a 12-month period, the Company is currently only able to issue a limited number of shares which aggregate to no more than one-third of its public float using the Shelf. As of December 31, 2023, no sales had been made pursuant to the ATM Program. Subsequent to December 31, 2023 and through March 21, 2024, we have sold and issued 109,485 shares of common stock under the ATM Program, with total net proceeds of $ 0.2 million .

Warrants

Warrants	12 Months Ended
Warrants	Dec. 31, 2023
Warrants and Rights Note Disclosure [Abstract]
Warrants	10. Warrants The Company has the following warrants outstanding for the purchase of common stock as of December 31, 2023 and 2022: WARRANTS SHARES OF EXERCISE EXPIRATION DATES Series B Warrants 3,672,484 $ 6.81 November 2025 Conditional Series B Warrants 3,672,484 $ 6.81 November 2025 NC Ohio Trust 162,740 $ 1.46 March 2029 Series B Warrants In connection with the November 13, 2018 issuance of Series B convertible preferred stock (the Series B Preferred), the Company issued to the purchaser of the Series B Preferred warrants to purchase 3,672,484 shares of common stock for $ 6.81 per share (the Series B Warrants), which became fully exercisable upon issuance. The Series B Warrants contain provisions allowing cashless exercise. In addition, the Company issued to the same stockholder additional five-year warrants for the purchase of 3,672,484 shares of common stock for $ 6.81 per share (the Conditional Series B Warrants), which become exercisable in the event that the Company completes a future financing that meets certain financial milestones or achieves certain share prices as follows: • 918,121 shares vest upon (1) a financing event effected through the sale of our equity securities to third parties resulting in at least $ 20,000,000 in gross proceeds with a per share price of $ 12.47 , or (2) an average market price (determined over a consecutive 10 -day period) of $ 12.47 per share; • an additional 918,121 shares vest upon (1) a financing event with a price per share of $ 13.20 , or (2) an average market price (determined over a consecutive 10 -day period) of, $ 13.20 per share; • an additional 918,121 shares vest upon (1) a financing event with a per share price of $ 13.94 , or (2) an average market price (determined over a consecutive 10 -day period) of, $ 13.94 per share; and • an additional 918,121 shares vest upon (1) a financing event with a per share price of $ 14.68 , or (2) an average market price (determined over a consecutive 10 -day period) of, $ 14.68 per share. On June 24, 2021, the Company’s board of directors approved and on July 14, 2021 the stockholders approved, effective upon the closing of the IPO, an amendment to the terms of the Series B Warrants and the Conditional Series B Warrants to extend the expiration date from November 2023 to November 2025 . In addition, the exercise period for the Conditional Series B Warrants was amended such that in the event the future financing milestones or certain share price targets described above are achieved, the Conditional Series B Warrants can only be exercised in conjunction with the sale of the Company, on a cash or cashless exercise basis, or otherwise in November 2025 through a cashless exercise. The Company recorded the Series B Warrants as a component of stockholder’s equity at the time of issuance at their estimated fair value of $ 2.1 million and recorded the Conditional Series B Warrants as a liability on the consolidated balance sheet as the number of shares used to calculate the settlement is not a fixed number of shares. The Conditional Series B Warrants are remeasured to their fair value at each reporting date with changes in the fair value recognized as a component of other income (expense), net in the consolidated statements of operations. The Company will continue to recognize changes in the fair value of the Conditional Series B Warrants until each Conditional Series B Warrant is exercised, expires or qualifies for equity classification. The warrant liability fair value was $ 0.9 million and $ 1.9 million as of December 31, 2023 and 2022, respectively. NC Ohio Trust Warrants On March 20, 2019, the Company established the NC Incorporated Ohio Trust, an irrevocable trust funded by the Company. The beneficiary in the trust agreement has provided past services to the Company for more than 15 years and is a non-employee. The warrant provides the beneficiary the right to purchase 162,740 shares of the Company’s common stock, $ 0.01 par value at an exercise price of $ 1.46 per share, subject to adjustments as specified in the warrant agreement. The Company recognizes the warrants as compensation expense within the consolidated statement of operations when the warrants are granted or at the service inception date if the service inception date precedes the grant date. In the period in which the grant date occurs, cumulative compensation cost shall be adjusted to reflect the cumulative effect of measuring compensation cost based on the fair value at the grant date rather than the fair value previously used at the service inception date or subsequent reporting dates. As of December 31, 2023 and 2022 , a grant date was not established as there was not a mutual understanding of key terms. The Company remeasures the fair value of the award at each reporting date, as the service date preceded the grant date. The value of the warrants for 162,740 shares of common stock was $ 0.2 million as of both December 31, 2023 and 2022 , and was recorded as stock compensation expense within research and development expense and a credit to stockholders’ equity in the consolidated financial statements.

Stock Options, Restricted Stock

Stock Options, Restricted Stock and Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock Options, Restricted Stock and Stock-Based Compensation	11. Stock Options, Restricted Stock and Stock-Based Compensation Equity Incentive Plans The Company’s 2015 Stock Plan, as amended, (the 2015 Plan) provides for the Company to sell or issue common shares or restricted common stock, or to grant incentive stock options or nonqualified stock options for the purchase of common stock, to employees, members of the board of directors and consultants of the Company. The 2015 Plan is administered by the board of directors and exercise prices, vesting and other restrictions are determined at its discretion. All stock option grants are non-statutory stock options except option grants to employees intended to qualify as incentive stock options under the Internal Revenue Code of 1986, as amended. Incentive stock options may not be granted at less than the fair market value of the Company’s common stock on the date of grant, as determined in good faith by the board of directors at its sole discretion. Nonqualified stock options may be granted at an exercise price established by the board of directors at its sole discretion and the vesting periods may vary. Vesting periods are generally four years and are determined by the board of directors. Stock options become exercisable as they vest. Options granted under the 2015 Plan expire no more than ten years from the date of grant. As of December 31, 2023 , there are no shares available for grants under the 2015 Plan and the 2015 Plan continues to govern the terms and conditions of the outstanding awards under the 2015 Plan. On July 14, 2021, the Company’s 2021 Equity Incentive Plan (the 2021 Plan) was approved by the Company’s stockholders, and became effective upon completion of the IPO and serves as the successor to the 2015 Plan. 5,321,447 shares of common stock are reserved under the 2021 Plan, of which 252,053 shares remain available for future grants as of December 31, 2023. Stock Options Stock option activity is summarized as follows: NUMBER OF WEIGHTED- WEIGHTED- AGGREGATE Outstanding as of December 31, 2022 5,645,420 $ 2.77 7.73 Granted 1,313,203 1.30 Exercised — — Cancelled, forfeited or expired ( 1,292,002 ) 2.60 Outstanding as of December 31, 2023 5,666,621 $ 2.47 6.61 $ 199 Exercisable as of December 31, 2023 3,656,582 $ 2.49 5.55 $ 26 Unvested as of December 31, 2023 2,010,039 $ 2.44 8.54 $ 173 The 2015 Plan permits participants to use common stock they previously acquired to pay for the exercise of stock options based upon the fair value on the date of exercise. In connection with the exercise of a stock options to purchase 306,518 shares of our common stock at an exercise price of $ 1.46 , option holders tendered 122,608 shares of our common stock previously acquired in consideration of the full aggregate exercise price in accordance with the terms of the option and the 2015 Plan. The shares tendered are recorded as treasury stock within the Company's consolidated financial statements at December 31, 2023. The fair value of stock options granted was estimated on the grant date using the Black-Scholes option pricing model based on the following assumptions: YEAR ENDED DECEMBER 31, 2023 2022 Expected option life (years) 5.48 - 6.08 5.33 - 6.08 Risk-free interest rate 3.50 % - 4.86 % 1.69 % - 4.23 % Expected volatility 91.33 % - 94.51 % 85.09 % - 87.67 % Expected dividend yield 0 % 0 % The total intrinsic value of stock options vested during each of the years ended December 31, 2023 and 2022 was zero . Restricted Stock Units Under the terms of the restricted stock unit agreements covering the common stock, shares of common stock related to restricted stock units are subject to time-based vesting. The restricted stock units will immediately be forfeited to the Company if the relationship between the recipient and the Company ceases. Restricted stock activity is summarized as follows: NUMBER OF WEIGHTED- Unvested at December 31, 2022 612,366 $ 1.71 Granted 2,242,509 $ 0.98 Vested ( 306,185 ) $ 1.71 Forfeited ( 22,258 ) $ 1.71 Unvested at December 31, 2023 2,526,432 $ 1.06 The aggregate fair value of restricted stock units that vested during each of the years ended December 31, 2023 and 2022 was $ 0.5 million and zero , respectively . Stock-Based Compensation Stock-based compensation expense for the years ended December 31, 2023 and 2022 was classified in the consolidated statements of operations as follows (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Research and development $ 1,347 $ 774 General and administrative 1,744 1,533 Total stock based compensation expense $ 3,091 $ 2,307 As of December 31, 2023 and 2022, total unrecognized compensation cost related to the unvested stock-based awards was $ 6.1 million and $ 7.6 million , respectively. As of December 31, 2023 and 2022, these amounts are expected to be recognized over a weighted average period of 2.40 and 2.42 years , respectively.

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes Due to the Company's net losses for 2023 and 2022 , as well as the full valuation allowance on its net deferred tax assets as discussed below, the Company did no t record any income tax expense or benefit for the years ended December 31, 2023 and 2022 . A reconciliation of the Company's statutory income tax rate to the Company’s effective income tax rate is as follows: YEAR ENDED 2023 2022 Income at US statutory rate 21.0 % 21.0 % Permanent adjustments ( 1.3 )% ( 2.8 )% Mark to market 0.5 % 18.3 % State taxes, net of federal benefit 6.9 % 12.8 % Valuation allowance ( 30.0 )% ( 56.9 )% Tax credits 2.9 % 7.6 % — — On October 4, 2023, the Governor of Massachusetts signed into law a bill that included the adoption of a single sales apportionment factor effective on January 1, 2025. As required under ASC 740, the Company has accounted for the deferred tax impacts of this tax law change in the period the tax law was enacted, which has the impact of reducing its state deferred tax assets. The impact of the tax law change is offset by a change in valuation allowance. Net deferred tax assets as of December 31, 2023 and 2022 consist of the following (in thousands): YEAR ENDED 2023 2022 Deferred tax assets: Net operating losses $ 23,136 $ 17,748 Intangibles 506 572 Accrued expenses and other 434 601 Deferred revenue — — Lease liability 406 524 Stock compensation 1,168 863 Capitalized R&D expenditures 9,200 4,931 Credits 6,199 4,755 Total deferred tax assets 41,049 29,994 Valuation allowance ( 40,548 ) ( 29,166 ) Net deferred tax assets 501 828 Deferred tax liabilities: Right of use asset ( 223 ) ( 284 ) Other ( 278 ) ( 544 ) Total deferred tax liabilities ( 501 ) ( 828 ) Net deferred tax assets (liabilities) $ — $ — As of December 31, 2023 , the Company has gross federal and state net operating loss carryforwards of approximately $ 86.2 million and $ 79.6 million which begin to expire in 2027 and 2032 , respectively. Additionally, the Company has $ 77.4 million of the federal net operating loss carryforwards that can be carried forward indefinitely. As of December 31, 2023 , the Company has gross federal and state tax credit carryforwards of approximately $ 4.5 million and $ 2.2 million, respectively, which begin to expire in 2036 and 2030 , respectively. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards and certain tax credits. Management has considered the Company’s history of cumulative net losses incurred since inception, as well as its lack of product revenue since inception, and has determined that it is more likely than not that the Company will not realize the benefits of its deferred tax assets. As a result, a full valuation allowance has been established at December 31, 2023 and 2022. Section 382 of the Internal Revenue Code of 1986, as amended (Section 382), contains rules that limit the ability of a company that undergoes in ownership change to utilize its net operating losses (NOLs) and tax credits existing as of the date of such ownership change. Under the rules, such an ownership change is generally any change in ownership of more than 50% of a company’s stock within a rolling three-year period. The rules generally operate by focusing on changes in ownership of all stock considered by the rules as owning, directly or indirectly, 5% or more of the stock of a company and any change in ownership arising from new issuances of stock by the company. The Company has not yet determined if such a limitation would be placed against its available net operating losses. The Company will make such a determination prior to the utilization of any future net operating losses. A summary of changes in the valuation allowance for deferred tax assets during the years ended December 31, 2023 and 2022 were as follows (in thousands): YEAR ENDED 2023 2022 Valuation allowance $ 29,166 $ 18,493 Increases recorded to income tax provision 11,382 10,673 Decreases recorded to income tax provision — — Valuation allowance $ 40,548 $ 29,166 The Company files income tax returns in the United States and various state and local jurisdictions. The federal and state tax returns are generally subject to examination for the years ended December 31, 2014 through December 31, 2023 . There are currently no pending tax examinations . To the extent the Company has tax attribute carryforwards, the tax year in which the attribute was generated may still be adjusted upon examination.

Exclusive Licensing Agreement w

Exclusive Licensing Agreement with a Related Party	12 Months Ended
Exclusive Licensing Agreement with a Related Party	Dec. 31, 2023
License Agreement [Abstract]
Exclusive Licensing Agreement with a Related Party	13. Exclusive Licensing Agreement with a Related Party In March 2014, the Company entered into an exclusive licensing agreement with Ventagen, LLC (Ventagen) which provides Ventagen the right to develop products for commercial sale and distribution within Mexico, Belize, Guatemala, Honduras, El Salvador, Costa Rica, Nicaragua, Panama, Colombia, and Bolivia (the Territory). Ventagen paid the Company $ 1.0 million upon the signing of the agreement and agreed to a fixed future payment to the Company of $ 2.5 million. The future payment will be made upon the achievement of $ 5.0 million of sales of an approved product by Ventagen and is subject to reduction if Ventagen’s costs to develop an approved product exceeds $ 4.0 million. In addition to the upfront payment and the future payment, Ventagen agreed to purchase from the Company all manufactured product that is required for clinical or commercial purposes at a price of cost plus 25 % of the wholesale price of the approved product, subject to a minimum or maximum price. In the event the Company is unable or unwilling to manufacture supply under the terms of the agreement, Ventagen has the right to manufacture its own supply and will be required to pay a fixed fee per dose sold. The Company also agreed to provide certain services to Ventagen related to Ventagen’s development plan. Stockholders of the Company own 49.5 % of the voting stock of Ventagen, including 47 % by the Company’s founders who are currently significant stockholders of the Company, and trusts for the benefit of their children. The Company had completely recognized the $ 1.0 million upfront license fee as research and development service revenue as of December 31, 2022.

Technology License Agreement

Technology License Agreement	12 Months Ended
Technology License Agreement	Dec. 31, 2023
Technology License Agreement [Abstract]
Technology License Agreement	14. Technology License Agreement On January 20, 2018 the Company entered into an exclusive option agreement (Option Agreement) with MGB. Pursuant to the Option Agreement, the Company has obtained the exclusive right from MGB to negotiate an exclusive license to make, develop and commercialize rQNestin, a genetically modified oncolytic herpes simplex virus for the treatment of certain types of cancers. Pursuant to the Option Agreement, the Company will support a clinical trial to be conducted at MGB pursuant to the terms of a clinical trial agreement to be negotiated and the Company has committed to remitting $ 0.8 million in support of such clinical trial over the course of approximately three years . Upon execution of the Option Agreement, the Company remitted a non-refundable fee of $ 40,000 to MGB to be applied toward the Company’s on-going obligations to reimburse patent expenses. During the years ended December 31, 2023 and 2022 , the Company did no t expense any startup and patient fees for clinical trials performed by MGB. On September 15, 2020, the Company exercised the Option Agreement with MGB and entered into an exclusive worldwide patent license agreement with MGB (the MGB License). In connection with the MGB License, the Company paid a fee of $ 0.1 million and agreed to reimburse patent costs incurred by MGB, including $ 0.1 million paid at the time of entering into the MGB License. Prior to the first commercial sale, the Company is required to pay MGB an annual license fee of $ 50,000 beginning following the fourth anniversary of the effective date. The MGB License contains cumulative milestone payments equaling a maximum amount of $ 39.0 million upon the achievement of various clinical, commercial and sales milestones of both primary and secondary products. Following the first commercial sale, the Company is required to pay royalties to MGB, which are paid at an increasing rate as net sales increase, ranging from low single digits to high single digits. In addition, after the first commercial sale, the Company is required to pay MGB a pre-determined fixed annual minimum royalty, which amount may be credited against earned royalties starting in the fourth year following the first commercial sale. The Company also agreed to pay a single digit royalty rate on net sales of any derived products.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	15. Commitments and Contingencies Guarantees The Company has identified the guarantees described below as disclosable, in accordance with ASC 460, Guarantees. As permitted under Delaware law, the Company indemnifies its officers and directors for certain events or occurrences while the officer or director is, or was, serving at the Company’s request in such capacity. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ insurance coverage that should limit its exposure and enable it to recover a portion of any future amounts paid. The Company is a party to a number of agreements entered into in the ordinary course of business that contain typical provisions that obligate the Company to indemnify the other parties to such agreements upon the occurrence of certain events. Such indemnification obligations are usually in effect from the date of execution of the applicable agreement for a period equal to the applicable statute of limitations. The aggregate maximum potential future liability of the Company under such indemnification provisions is uncertain. The Company leases office space under a noncancelable operating lease expiring in 2026 . The Company has standard indemnification arrangements under this lease that require it to indemnify the landlord against all costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from any breach, violation, or nonperformance of any covenant or condition of the lease. As of December 31, 2023 , the Company had no t experienced any losses related to these indemnification obligations, and no material claims with respect thereto were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves have been established. Legal Proceedings From time to time, we may become involved in litigation or other legal proceedings. On December 15, 2022, Periphagen notified us by letter of its claim that we have failed to use commercially reasonable efforts to complete a human proof of concept clinical trial of an NT-3 Asset under an Exclusive License Agreement dated December 9, 2019 between us and Periphagen (the Periphagen License Agreement). On January 13, 2023, we filed a demand for arbitration against Periphagen with the American Arbitration Association, seeking a declaration that Periphagen’s December 15 letter failed to comply with the dispute and escalation provisions in the Periphagen License Agreement. On March 10, 2023, Periphagen filed its answer and counterclaims to our demand for arbitration. In its counterclaims, Periphagen sought a declaration that we have not used commercially reasonable efforts to complete a human proof of concept clinical trial of the NT-3 Asset and a declaration that any further extension of time would not be scientifically or commercially reasonable. We denied Periphagen’s counterclaims. On June 7, 2023, the parties entered into an amendment to the Exclusive License Agreement that resolved the dispute and resulted in termination of the arbitration without any financial impact. Aside from the proceeding with Periphagen, we are not currently a party to any litigation or legal proceedings that, in the opinion of our management, are probable to have a material adverse effect on our business. Regardless of outcome, litigation can have an adverse impact on our business, financial condition, results of operations and prospects because of defense and settlement costs, diversion of management resources and other factors.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
Net Loss Per Share	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	16. Net Loss Per Share Net Loss Per Share Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share data): YEAR ENDED DECEMBER 31, 2023 2022 Numerator: Net loss $ ( 37,939 ) $ ( 18,794 ) Denominator: Weighted-average shares of common stock outstanding-basic and diluted 28,935,289 28,823,480 Net loss per share -basic and diluted $ ( 1.31 ) $ ( 0.65 ) The Company’s potentially dilutive securities have been excluded from the computation of dilutive net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential shares of common stock from the computation of diluted net loss per share because including them would have had an anti-dilutive effect. YEAR ENDED DECEMBER 31, 2023 2022 Outstanding warrants for common stock 7,507,708 7,507,708 Outstanding stock options (as converted to common stock) 5,666,621 5,645,420 Unvested restricted stock 2,526,432 612,366 15,700,761 13,765,494

Corporate Restructuring

Corporate Restructuring	12 Months Ended
Corporate Restructuring	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Corporate Restructuring	17. Corporate Restructuring In November 2023, the Company's Board of Directors authorized a restructuring plan to focus on continuation and expansion of development of CAN-3110 as well as the enLIGHTEN TM Discovery Platform, which resulted in a reduction of the Company’s workforce by approximately 45 % . Each affected employee's separation from the Company occurred in December 2023. As a result, the Company incurred costs of $ 0.7 million related to severance benefits for the affected employees, including severance payments and limited reimbursement of medical insurance premiums. The restructuring plan is expected to be completed in the first quarter of 2024 once the remaining unpaid severance payments of $ 46,000 are made. Of the $ 0.7 million in costs recognized related to the restructuring plan, $ 0.5 million and $ 0.2 million have been charged to research and development and general and administrative expenses, respectively, in the accompanying consolidated statement of operations for the year ended December 31, 2023. During the year ended December 31, 2023, the Company paid $ 0.7 million in severance benefits to separating employees related to the restructuring plan. At December 31, 2023, unpaid severance costs of $ 46,000 are included in accrued expenses in the accompanying consolidated balance sheet and are expected to be paid during the first quarter of 2024.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting standards set by the Financial Accounting Standards Board (FASB). The FASB sets generally accepted accounting principles (GAAP) that the Company follows to ensure its financial condition, results of operations, and cash flows are consistently reported. References to GAAP issued by the FASB in these notes to the financial statements are to the FASB Accounting Standards Codification (ASC). The Company has reclassified certain amounts relating to its prior period results to conform to its current period presentation.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Candel Therapeutics, Inc. and its wholly owned subsidiary Candel Therapeutics Securities Corporation. All intercompany transactions and balances have been eliminated.
Segment Information	Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company and the Company's chief operating decision maker, the Company's chief executive officer, views the Company's operations and manages its business as a single operating segment. The Company only operates in the United States.
Emerging Growth Company	Emerging Growth Company The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the Jobs Act). Under the Jobs Act emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the Jobs Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the Jobs Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company’s management evaluates its estimates, which include but are not limited to management’s judgments of accrued expenses, valuation of stock-based option awards, valuations of warrants, and income taxes. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original final maturities of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents comprise marketable securities with maturities of less than three months when purchased. Cash equivalents are reported at fair value.
Restricted Cash	Restricted Cash The Company had $ 0.3 million of restricted cash as of both December 31, 2023 and 2022 , which represents cash held as a security deposit under the terms of the Company’s Needham, Massachusetts facility lease.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. 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 that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The carrying values of cash and cash equivalents (considered as Level 1 measurements), accounts payable, and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities. The carrying value of the Company's term loan approximates fair value due to the variable interest rate. The Company’s warrant liability is carried at fair value and is classified as Level 3 measurement.
Property and Equipment	Property and Equipment Property and equipment consist of laboratory and manufacturing equipment, networking and computer equipment, furniture and fixtures and leasehold improvements. Property and equipment are recorded at cost, and depreciated using the straight-line method over the estimated useful lives of the respective assets: ASSET ESTIMATED USEFUL LIFE Networking and computer equipment 5 years Laboratory equipment 5 years Manufacturing equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of the useful life or remaining lease term
Leases	Leases The Company adopted ASC 842 as of January 1, 2022 and elected the transition method under ASU 2016-02 whereby the Company records a right-of-use asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. The Company also elected to apply the practical expedients intended to ease transition. Accordingly, the Company has only applied ASC 842 to leases existing as of January 1, 2022. The Company determines if an arrangement is, or contains, a lease at inception. Lease right of use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Lease right of use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments to be made over the lease term. The lease right of use asset is equal to the lease liability and adjusted for prepaid rent, initial direct costs, and incentives. As the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term. The Company has elected to not apply the recognition requirements of ASC 842 for short-term leases, which is defined as a lease that, at the lease commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the Company is reasonably certain to exercise. For real estate lease agreements entered into or modified after the adoption of ASC 842 that include lease and non-lease components, the Company has elected to account for the lease and non-lease components, such as common area maintenance charges, as a single lease component term.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Periodically, the Company maintains deposits in accredited financial institutions in-excess of the federally insured limits. The Company deposits its cash in financial institutions with a high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal risk associated with commercial banking relationships.
Impairment of Long-lived Assets	Impairment of Long-lived Assets Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. Long-lived assets consist of fixed assets and operating lease assets. In the third and fourth quarters of 2023, the Company recorded impairment charges totaling approximately $ 0.4 million related to manufacturing equipment that the Company has determined it does not plan to use for its intended use, and the Company recorded an impairment to reduce the carrying value to its estimated fair value. The Company has not recorded any other impairment losses on such long-lived assets.
Revenue Recognition	Revenue Recognition The Company applies Accounting Standards Codification (ASC), Topic 606, Revenue from Contracts with Customers, (ASC 606). This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity 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 entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and then assesses whether or not each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.
Research and Development Costs and Accruals	Research and Development Costs and Accruals Research and development expenses include salaries and benefits, materials and supplies, preclinical and clinical trial expenses, stock-based compensation expense, depreciation of equipment, contract services and other outside expenses. The Company has entered into various research and development-related contracts with clinical and research institutions, contract research organizations, and other companies. These agreements are generally cancelable, and related payments are recorded as research and development expenses as incurred. Costs of certain development activities, such as manufacturing, pre-clinical and clinical trial expenses, are recognized based on an evaluation of the progress to completion of specific tasks. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid or accrued research and development costs. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. Costs incurred in obtaining technology licenses and intellectual property are charged to research and development expenses as acquired in-process research and development if the technology licensed or intellectual property acquired has not reached technological feasibility and has no alternative future use.
Patent Costs	Patent Costs All patent-related costs incurred in connection with preparing, filing, maintaining and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified in general and administrative expenses.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for its stock-based compensation in accordance with ASC Topic 718, Compensation—Stock Compensation (ASC 718). ASC 718 requires all share-based payments to employees and directors to be recognized as expense in the consolidated statements of operations based on their grant date fair values. In addition, in accordance with FASB Accounting Standards Update (ASU) 2016-09 which identifies areas for simplification of several areas of share-based payment transactions, the Company treats non-employee grants the same as employee grants. The Company estimates the fair value of options granted using the Black-Scholes option pricing model for stock option grants to both employees and non-employees. The Company believes the fair value of the stock options granted to non-employees is more reliably determinable than the fair value of the services provided. The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate and (d) expected dividends. Due to a lack of company-specific historical and implied volatility data, the Company has based its computation of expected volatility on a combination of the historical volatility of the Company and of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus. The historical volatility is calculated based on a period of time commensurate with the expected term assumption. The Company uses the simplified method as prescribed by the SEC Staff Accounting Bulletin No. 107, Share-Based Payment, to calculate the expected term for options granted to employees as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The expected term is applied to the stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among its employee population. For options granted to non-employees, the Company utilizes the contractual term of the share-based payment as the basis for the expected term assumption. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company generally expenses the fair value of its share-based compensation awards to employees and non-employees on a straight-line basis over the requisite service period, which is generally the vesting period.
Government Grants	Government Grants The Company has applied for grants for the reimbursement of expenditures with the Massachusetts Life Sciences Center for certain qualified operating expenditures, including employee related costs. The Company recognizes government grants when there is reasonable assurance that the Company will comply with the conditions attached to the grant arrangement and the grant will be received. Government grants are recorded as grant income and classified in other income in the consolidated statements of operations. The Company recognized government grants of zero and $ 48,000 for the years ended December 31, 2023 and 2022 , respectively. Grant income is recognized as a component of other income/(expense), net in the consolidated statements of operations.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method in accordance with ASC Topic 740, Income Taxes (ASC 740) which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. At December 31, 2023 and 2022, the Company has concluded that a full valuation allowance is necessary for its deferred tax assets (see Note 12). The Company accounts for uncertainty in income taxes, by applying the two-step process to determine the amount of tax benefit to be recognized in the financial statements. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax is then assessed as the amount of benefits to be recognized in the consolidated financial statements. The amount of benefits that may be used are the largest amounts that have a greater than 50 % likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves or unrecognized tax benefits that are considered appropriate as well as the related net interest received.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period and, if dilutive, the weighted-average number of potential shares of common stock. In periods where the Company reports a net loss attributable to common stockholders, diluted net loss per share is the same as basic net loss per share, since dilutive shares of common stock are not assumed to have been issued if their effect is anti-dilutive. Diluted net loss per share is the same as basic net loss per share for the years ended December 31, 2023 and 2022 since all potential shares of common stock instruments are anti-dilutive as a result of the loss for such periods.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC's Disclosure Update and Simplification Initiative, which modifies the disclosure or presentation requirements related to a variety of FASB Accounting Standard Codification topics. The effective date for each amendment will be the date on which the SEC's removal of that related disclosure from Regulation S-X or Regulation S-K is effective, with early adoption prohibited. If by June 30, 2027, the SEC has not removed the applicable requirement from Regulation S-X or Regulation S-K, the pending content of the associated amendment will be removed from the Codification and will not become effective for any entities. The Company is currently evaluating the potential impact that ASU 2023-06 may have on its consolidated financial statements and related disclosures. In November 2023, the FASB issued ASU 2023-07, Segment Reporting: Improvements to Reportable Segment Disclosures, which amends guidance in ASC 280, Segment Reporting The amendments in this ASU expand segment disclosure requirements, including new segment disclosure requirements for entities with a single reportable segment, among other disclosure requirements. The ASU’s amendments are effective for public business entities for annual periods beginning after December 15, 2023. Early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of ASU 2023-07 may have have on its consolidated financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures, which amends the guidance in ASC 740, Income Taxes. The ASU is intended to improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. The ASU’s amendments are effective for public business entities for annual periods beginning after December 15, 2024. Early adoption is permitted. Adoption can be either prospectively or retrospectively applied, and the Company will adopt this ASU on a prospective basis. The Company is currently evaluating the potential impact that ASU 2023-09 may have on its consolidated financial statements and related disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
Summary of Significant Accounting Policies (Tables)	Dec. 31, 2023
Accounting Policies [Abstract]
Property and Equipment Estimated Useful Lives	Property and equipment are recorded at cost, and depreciated using the straight-line method over the estimated useful lives of the respective assets: ASSET ESTIMATED USEFUL LIFE Networking and computer equipment 5 years Laboratory equipment 5 years Manufacturing equipment 5 years Furniture and fixtures 5 years Leasehold improvements Shorter of the useful life or remaining lease term

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	12 Months Ended
Fair Value of Financial Assets and Liabilities (Tables)	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Information About Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): FAIR VALUE MEASUREMENTS AS OF LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Liabilities: Warrant liability — — 916 916 Total $ — $ — $ 916 $ 916 FAIR VALUE MEASUREMENTS AS OF LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Liabilities: Warrant liability — — 1,882 1,882 Total $ — $ — $ 1,882 $ 1,882
Schedule of Aggregate Fair Values of Warrant Liabilities, for Which Fair Value Determined by Level 3 Inputs	The following table provides a roll forward of the aggregate fair values of the Company’s warrant liability, for which fair value is determined by Level 3 inputs (in thousands): SERIES B Balance at December 31, 2021 $ 18,252 Change in fair value ( 16,370 ) Balance at December 31, 2022 $ 1,882 Change in fair value ( 966 ) Balance at December 31, 2023 $ 916

Fixed Assets, Net (Tables)

Fixed Assets, Net (Tables)	12 Months Ended
Fixed Assets, Net (Tables)	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Summary of Fixed Assets, Net	Fixed assets, net consisted of the following (in thousands): DECEMBER 31, 2023 2022 Laboratory equipment $ 1,209 $ 1,055 Manufacturing equipment 730 1,201 Furniture and fixtures 159 159 Networking and computer equipment 88 81 Leasehold improvements 3,109 3,057 Total fixed assets $ 5,295 $ 5,553 Less: accumulated depreciation ( 2,089 ) ( 1,129 ) Fixed assets, net $ 3,206 $ 4,424

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
Accrued Expenses (Tables)	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): DECEMBER 31, 2023 2022 Payroll and employee related expenses $ 2,017 $ 2,647 Third-party research and development expenses 1,811 1,486 Professional fees and other 528 590 $ 4,356 $ 4,723

Term Loan (Tables)

Term Loan (Tables)	12 Months Ended
Term Loan (Tables)	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Principal Payments and Net Carrying Amount of Term Loan	The scheduled principal payments and net carrying amount of the term loan are as follows (in thousands): YEAR ENDING DECEMBER 31, 2024 $ 9,167 2025 10,000 2026 833 Total principal 20,000 Final payment fee 900 Less: debt discount ( 989 ) Accretion of debt discount 614 Net carrying amount $ 20,525 Less current portion $ ( 8,893 ) Long-term portion $ 11,632

Lease (Tables)

Lease (Tables)	12 Months Ended
Lease (Tables)	Dec. 31, 2023
Leases [Abstract]
Schedule of Other Information	YEAR ENDED DECEMBER 31, Other Information 2023 2022 Operating cash flows used for operating leases (in thousands) $ 583 $ 567 Weighted-average remaining lease term (years) 2.7 3.7 Weighted-average incremental borrowing rate 7.02 % 7.02 %
Summary of Future Lease Payments Under Non-cancelable Leases	The future lease payments under non-cancelable leases at December 31, 2023, are as follows (in thousands): 2024 598 2025 613 2026 415 Total future lease payments 1,626 Less: imputed interest ( 140 ) Total lease liability $ 1,486

Common Stock and Preferred St_2

Common Stock and Preferred Stock (Tables)	12 Months Ended
Common Stock and Preferred Stock (Tables)	Dec. 31, 2023
Equity [Abstract]
Schedule of Common Stock Reserved For Future Issuance	Common Stock Reserved The Company has reserved the following shares of common stock for future issuance as of: DECEMBER 31, 2023 2022 Stock options outstanding 5,666,621 5,645,420 Unvested restricted stock 2,526,432 612,366 Shares available for future grant under stock option plan 252,053 1,311,915 Warrants 7,507,708 7,507,708 15,952,814 15,077,409

Capital Stock (Tables)

Capital Stock (Tables)	12 Months Ended
Capital Stock (Tables)	Dec. 31, 2023
Capital Stock [Abstract]
Schedule of Common Stock Reserved For Future Issuance	Common Stock Reserved The Company has reserved the following shares of common stock for future issuance as of: DECEMBER 31, 2023 2022 Stock options outstanding 5,666,621 5,645,420 Unvested restricted stock 2,526,432 612,366 Shares available for future grant under stock option plan 252,053 1,311,915 Warrants 7,507,708 7,507,708 15,952,814 15,077,409

Warrants (Tables)

Warrants (Tables)	12 Months Ended
Warrants (Tables)	Dec. 31, 2023
Warrants and Rights Note Disclosure [Abstract]
Summary of Warrants Outstanding for Purchase of Common Stock	The Company has the following warrants outstanding for the purchase of common stock as of December 31, 2023 and 2022: WARRANTS SHARES OF EXERCISE EXPIRATION DATES Series B Warrants 3,672,484 $ 6.81 November 2025 Conditional Series B Warrants 3,672,484 $ 6.81 November 2025 NC Ohio Trust 162,740 $ 1.46 March 2029

Stock Options, Restricted Sto_2

Stock Options, Restricted Stock and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Option Activity	Stock option activity is summarized as follows: NUMBER OF WEIGHTED- WEIGHTED- AGGREGATE Outstanding as of December 31, 2022 5,645,420 $ 2.77 7.73 Granted 1,313,203 1.30 Exercised — — Cancelled, forfeited or expired ( 1,292,002 ) 2.60 Outstanding as of December 31, 2023 5,666,621 $ 2.47 6.61 $ 199 Exercisable as of December 31, 2023 3,656,582 $ 2.49 5.55 $ 26 Unvested as of December 31, 2023 2,010,039 $ 2.44 8.54 $ 173
Schedule of Fair Value of Stock Options Granted Was Estimated on Black-Scholes Options	The fair value of stock options granted was estimated on the grant date using the Black-Scholes option pricing model based on the following assumptions: YEAR ENDED DECEMBER 31, 2023 2022 Expected option life (years) 5.48 - 6.08 5.33 - 6.08 Risk-free interest rate 3.50 % - 4.86 % 1.69 % - 4.23 % Expected volatility 91.33 % - 94.51 % 85.09 % - 87.67 % Expected dividend yield 0 % 0 %
Summary of Restricted Stock Activity	Restricted stock activity is summarized as follows: NUMBER OF WEIGHTED- Unvested at December 31, 2022 612,366 $ 1.71 Granted 2,242,509 $ 0.98 Vested ( 306,185 ) $ 1.71 Forfeited ( 22,258 ) $ 1.71 Unvested at December 31, 2023 2,526,432 $ 1.06
Schedule of Stock-based Compensation Expense	Stock-based compensation expense for the years ended December 31, 2023 and 2022 was classified in the consolidated statements of operations as follows (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Research and development $ 1,347 $ 774 General and administrative 1,744 1,533 Total stock based compensation expense $ 3,091 $ 2,307

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Reconciliation of Effective Income Tax Rate	A reconciliation of the Company's statutory income tax rate to the Company’s effective income tax rate is as follows: YEAR ENDED 2023 2022 Income at US statutory rate 21.0 % 21.0 % Permanent adjustments ( 1.3 )% ( 2.8 )% Mark to market 0.5 % 18.3 % State taxes, net of federal benefit 6.9 % 12.8 % Valuation allowance ( 30.0 )% ( 56.9 )% Tax credits 2.9 % 7.6 % — —
Schedule of Net Deferred Tax Assets	Net deferred tax assets as of December 31, 2023 and 2022 consist of the following (in thousands): YEAR ENDED 2023 2022 Deferred tax assets: Net operating losses $ 23,136 $ 17,748 Intangibles 506 572 Accrued expenses and other 434 601 Deferred revenue — — Lease liability 406 524 Stock compensation 1,168 863 Capitalized R&D expenditures 9,200 4,931 Credits 6,199 4,755 Total deferred tax assets 41,049 29,994 Valuation allowance ( 40,548 ) ( 29,166 ) Net deferred tax assets 501 828 Deferred tax liabilities: Right of use asset ( 223 ) ( 284 ) Other ( 278 ) ( 544 ) Total deferred tax liabilities ( 501 ) ( 828 ) Net deferred tax assets (liabilities) $ — $ —
Summary of Changes in Valuation Allowance for Deferred Tax Assets	A summary of changes in the valuation allowance for deferred tax assets during the years ended December 31, 2023 and 2022 were as follows (in thousands): YEAR ENDED 2023 2022 Valuation allowance $ 29,166 $ 18,493 Increases recorded to income tax provision 11,382 10,673 Decreases recorded to income tax provision — — Valuation allowance $ 40,548 $ 29,166

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Lease Payments	The future lease payments under non-cancelable leases at December 31, 2023, are as follows (in thousands): 2024 598 2025 613 2026 415 Total future lease payments 1,626 Less: imputed interest ( 140 ) Total lease liability $ 1,486

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
Net Loss Per Share (Tables)	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share data): YEAR ENDED DECEMBER 31, 2023 2022 Numerator: Net loss $ ( 37,939 ) $ ( 18,794 ) Denominator: Weighted-average shares of common stock outstanding-basic and diluted 28,935,289 28,823,480 Net loss per share -basic and diluted $ ( 1.31 ) $ ( 0.65 )
Schedule of Potential Shares of Common Stock Excluded from Computation of Diluted Net Loss Per Share	The Company excluded the following potential shares of common stock from the computation of diluted net loss per share because including them would have had an anti-dilutive effect. YEAR ENDED DECEMBER 31, 2023 2022 Outstanding warrants for common stock 7,507,708 7,507,708 Outstanding stock options (as converted to common stock) 5,666,621 5,645,420 Unvested restricted stock 2,526,432 612,366 15,700,761 13,765,494

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Details)		3 Months Ended	12 Months Ended
	Aug. 05, 2022 USD ($)	Mar. 21, 2024 USD ($) shares	Dec. 31, 2023 USD ($) Candidate $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Organization And Basis Of Presentation [Line Items]
Number of product candidates \| Candidate			2
Net Income (Loss)			$ (37,939,000)	$ (18,794,000)
Accumulated deficit			$ (137,028,000)	$ (99,089,000)
Common stock, shares, issued \| shares			29,213,627	29,042,418
Common stock par value \| $ / shares			$ 0.01	$ 0.01
Cash and cash equivalents			$ 35,413,000	$ 70,058,000
Combination of Common Stock, Preferred Stock, Debt Securities, Warrants and/or Units \| Maximum [Member]
Organization And Basis Of Presentation [Line Items]
Stock Issued During Period, Value, New Issues	$ 200,000,000
ATM Program \| Subsequent Event
Organization And Basis Of Presentation [Line Items]
Shares of common stock sold and issued \| shares		109,485
Net proceeds		$ 200,000
ATM Program \| Maximum [Member]
Organization And Basis Of Presentation [Line Items]
Stock Issued During Period, Value, New Issues	$ 75,000,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		12 Months Ended
	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segment \| Segment			1
Restricted cash	$ 300,000		$ 300,000	$ 300,000
Long-lived assets, impairment charge	$ 400,000	$ 400,000
Impairment long lived asset held for use statement of income or comprehensive income extensible enumeration not disclosed flag	true	true
Expected dividend assumed			$ 0
Grant revenue				48,000
Percentage income taxes benefits upon ultimate settlement			50%
Lease right of use assets	$ 816,000		$ 816,000	1,056,000
Lease liability	$ 1,486,000		1,486,000
Govenment
Significant Accounting Policies [Line Items]
Grant revenue			$ 0	$ 48,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Property and Equipment Estimated Useful Lives (Details)	Dec. 31, 2023
Significant Accounting Policies [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	Leasehold Improvements
Networking and Computer Equipment
Significant Accounting Policies [Line Items]
Estimated Useful Life	5 years
Laboratory Equipment
Significant Accounting Policies [Line Items]
Estimated Useful Life	5 years
Manufacturing Equipment
Significant Accounting Policies [Line Items]
Estimated Useful Life	5 years
Furniture and Fixtures
Significant Accounting Policies [Line Items]
Estimated Useful Life	5 years

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities - Schedule of Information About Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Liabilities:
Warrant liability	$ 916	$ 1,882
Total	916	1,882
Level 3
Liabilities:
Warrant liability	916	1,882
Total	$ 916	$ 1,882

Fair Value of Financial Asset_4

Fair Value of Financial Assets and Liabilities - Schedule of Aggregate Fair Values of Warrant Liabilities, for Which Fair Value Determined by Level 3 Inputs (Details) - Series B Warrant Liability - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance	$ 1,882	$ 18,252
Change in fair value	(966)	(16,370)
Balance	$ 916	$ 1,882

Fixed Assets, Net - Summary of

Fixed Assets, Net - Summary of Fixed Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total fixed assets	$ 5,295	$ 5,553
Less accumulated depreciation	(2,089)	(1,129)
Fixed assets, net	3,206	4,424
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total fixed assets	1,209	1,055
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Total fixed assets	730	1,201
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total fixed assets	159	159
Networking and Computer Equipment
Property Plant And Equipment [Line Items]
Total fixed assets	88	81
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total fixed assets	$ 3,109	$ 3,057

Fixed Assets, Net - Additional

Fixed Assets, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 960	$ 778

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Payroll and employee related expenses	$ 2,017	$ 2,647
Third-party research and development expenses	1,811	1,486
Professional fees and other	528	590
Accrued expenses	$ 4,356	$ 4,723

Term Loan - Additional Informat

Term Loan - Additional Information (Details)			12 Months Ended
Term Loan - Additional Information (Details)	Dec. 30, 2022 USD ($)	Feb. 24, 2022 USD ($) Installment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Loan, maximum borrowing capacity	$ 5,000,000
Long-term debt			$ 20,525,000
Cash proceeds amount equal to at least from the issuance and sale of equity securities	$ 75,000,000
Final payment fee			900,000
Loan Agreement
Debt Instrument [Line Items]
Loan agreement date		Feb. 24, 2022
Loan, maximum borrowing capacity		$ 25,000,000
Long-term debt		$ 20,000,000
Loan agreement period		4 years
Number of consecutive \| Installment		24
Interest expense			$ 2,500,000	$ 1,600,000
Weighted average effective interest rate			11.19%
Debt issuance costs			$ 89,000
Final payment fee			$ 900,000
Loan Agreement \| Term Loan
Debt Instrument [Line Items]
Debt instrument, payment		monthly
Debt instrument, commencing date		Feb. 01, 2024
Debt instrument, maturity date		Jan. 01, 2026
Debt instrument final payment fee percentage		4.50%
Loan Agreement \| Minimum
Debt Instrument [Line Items]
Debt instrument subject to prepayment premium percentage		1%
Loan Agreement \| Minimum \| Prime Rate \| Term Loan
Debt Instrument [Line Items]
Interest rate		2.50%
Loan Agreement \| Maximum
Debt Instrument [Line Items]
Debt instrument subject to prepayment premium percentage		3%
Loan Agreement \| Maximum \| Term Loan
Debt Instrument [Line Items]
Interest rate		5.75%

Term Loan - Schedule of Princip

Term Loan - Schedule of Principal Payments and Net Carrying Amount of Term Loan (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
2024	$ 9,167
2025	10,000
2026	833
Total principal	20,000
Final payment fee	900
Less: debt discount	(989)
Accretion of debt discount	614
Net carrying amount	20,525
Less current portion	(8,893)
Long-term portion	$ 11,632

Other Long-Term Debt - Addition

Other Long-Term Debt - Additional Information (Details) - Periphagen, Inc. - USD ($) $ in Millions		12 Months Ended
	Dec. 09, 2019	Dec. 31, 2023
Debt Instrument [Line Items]
Asset acquisition, assumption of promissory note	$ 1
Promissory note contractual interest rate	2%
Accrued interest due upon maturity period	2027-11
Estimated market rate for unsecured loan	15.83%
Business acquisition present value of future cash outflow	$ 0.4
Business acquisition carrying value of note		$ 0.8
Payment for outstanding note balance and accrued interest due		$ 1.4

Lease - Additional Information

Lease - Additional Information (Details) $ in Thousands		12 Months Ended
Lease - Additional Information (Details) $ in Thousands	Feb. 04, 2019 Squrefoot	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease cost		$ 400
Variable lease cost		100
Total lease expense		500	$ 500
Cash paid for amounts included in measurement of lease liability		$ 583	$ 567
Corporate, Clinical and Manufacturing Operations \| Massachusetts
Lessee, Lease, Description [Line Items]
Area of lease property \| Squrefoot	15,197
Lease expiration date	Aug. 31, 2026

Lease - Schedule of Other Infor

Lease - Schedule of Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating cash flows used for operating leases	$ 583	$ 567
Weighted-average remaining lease term (years)	2 years 8 months 12 days	3 years 8 months 12 days
Weighted-average incremental borrowing rate	7.02%	7.02%

Lease - Summary of Future Lease

Lease - Summary of Future Lease Payments Under Non-cancellable Leases (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 598
2025	613
2026	415
Total future lease payments	1,626
Less: imputed interest	(140)
Operating lease liability	$ 1,486

Lease - Summary of Future Minim

Lease - Summary of Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2022	$ 598
2023	613
2024	415
Total future lease payments	$ 1,626

Common Stock and Preferred St_3

Common Stock and Preferred Stock - Additional Information (Details) - USD ($)		3 Months Ended
	Aug. 05, 2022	Mar. 21, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Preferred stock, shares authorized			10,000,000	10,000,000
Preferred stock par value			$ 0.01	$ 0.01
Common stock, shares authorized			150,000,000	150,000,000
Common stock, par value			$ 0.01	$ 0.01
Common stock, shares, issued			29,213,627	29,042,418
Common stock, shares, outstanding			29,091,019	28,919,810
ATM Program \| Subsequent Event
Class of Stock [Line Items]
Shares of common stock sold and issued		109,485
Net proceeds		$ 200,000
Maximum \| Combination of Common Stock, Preferred Stock, Debt Securities, Warrants and/or Units
Class of Stock [Line Items]
Sale of stock under Shelf	$ 200,000,000
Maximum \| ATM Program
Class of Stock [Line Items]
Sale of stock under Shelf	75,000,000
Public float issuing securities	$ 75,000,000

Common Stock and Preferred St_4

Common Stock and Preferred Stock - Schedule of Common Stock Reserved For Future Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Common stock reserved for future issuance	15,952,814	15,077,409
Warrants
Class of Stock [Line Items]
Common stock reserved for future issuance	7,507,708	7,507,708
Stock Options Outstanding
Class of Stock [Line Items]
Common stock reserved for future issuance	5,666,621	5,645,420
Unvested Restricted Stock
Class of Stock [Line Items]
Common stock reserved for future issuance	2,526,432	612,366
Shares Available for Future Grant Under Stock Option Plan
Class of Stock [Line Items]
Common stock reserved for future issuance	252,053	1,311,915

Warrants - Summary of Warrants

Warrants - Summary of Warrants Outstanding for Purchase of Common Stock (Details) - $ / shares		12 Months Ended
	Jun. 24, 2021	Dec. 31, 2023	Dec. 31, 2022	Mar. 20, 2019	Nov. 13, 2018
Series B Warrants
Class Of Warrant Or Right [Line Items]
SHARES OF COMMON STOCK SUBJECT TO WARRANTS		3,672,484	3,672,484
EXERCISE PRICE PER SHARE		$ 6.81	$ 6.81		$ 6.81
EXPIRATION DATES	2023-11	2025-11	2025-11
Conditional Series B Warrants
Class Of Warrant Or Right [Line Items]
SHARES OF COMMON STOCK SUBJECT TO WARRANTS		3,672,484	3,672,484
EXERCISE PRICE PER SHARE		$ 6.81	$ 6.81
EXPIRATION DATES		2025-11	2025-11
NC Ohio Trust
Class Of Warrant Or Right [Line Items]
SHARES OF COMMON STOCK SUBJECT TO WARRANTS		162,740	162,740	162,740
EXERCISE PRICE PER SHARE		$ 1.46	$ 1.46	$ 1.46
EXPIRATION DATES		2029-03	2029-03

Warrants - Additional Informati

Warrants - Additional Information (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Jun. 24, 2021	Mar. 20, 2019 $ / shares shares	Dec. 31, 2023 USD ($) TradingDays $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Nov. 13, 2018 $ / shares shares
Class Of Warrant Or Right [Line Items]
Fair value of warrant liability \| $			$ 916	$ 1,882
Common stock, par value			$ 0.01	$ 0.01
Tranche One
Class Of Warrant Or Right [Line Items]
Proceeds from stock offering \| $			$ 20,000,000
Class of warrant or right exercise price per share			$ 12.47
Class of warrant or right exercise average market price per share			$ 12.47
Number of consecutive days \| TradingDays			10
Class of warrants issued \| shares			918,121
Tranche Two
Class Of Warrant Or Right [Line Items]
Class of warrant or right exercise price per share			$ 13.2
Class of warrant or right exercise average market price per share			$ 13.2
Number of consecutive days \| TradingDays			10
Class of warrants issued \| shares			918,121
Tranche Three
Class Of Warrant Or Right [Line Items]
Class of warrant or right exercise price per share			$ 13.94
Class of warrant or right exercise average market price per share			$ 13.94
Number of consecutive days \| TradingDays			10
Class of warrants issued \| shares			918,121
Tranche Four
Class Of Warrant Or Right [Line Items]
Class of warrant or right exercise price per share			$ 14.68
Class of warrant or right exercise average market price per share			$ 14.68
Number of consecutive days \| TradingDays			10
Class of warrants issued \| shares			918,121
Series B Warrants
Class Of Warrant Or Right [Line Items]
Class of warrant or right issued \| shares					3,672,484
Class of warrant or right period			5 years
Class of warrants issued per share			$ 6.81	$ 6.81	$ 6.81
Expiration dates	2023-11		2025-11	2025-11
Estimated fair value of warrants \| $			$ 2,100
Extended expiration dates	2025-11
Class of warrants issued \| shares			3,672,484	3,672,484
Series B Conditional Warrants
Class Of Warrant Or Right [Line Items]
Fair value of warrant liability \| $			$ 900	$ 1,900
Conditional Series B Warrants
Class Of Warrant Or Right [Line Items]
Class of warrants issued per share			$ 6.81	$ 6.81
Expiration dates			2025-11	2025-11
Class of warrants issued \| shares			3,672,484	3,672,484
NC Ohio Trust
Class Of Warrant Or Right [Line Items]
Class of warrants issued per share		$ 1.46	$ 1.46	$ 1.46
Expiration dates			2029-03	2029-03
Class of warrants issued \| shares		162,740	162,740	162,740
Common stock, par value		$ 0.01
Warrant liability \| $			$ 200	$ 200
NC Ohio Trust \| Minimum
Class Of Warrant Or Right [Line Items]
Past services provided by beneficiary		15 years

Stock Options, Restricted Sto_3

Stock Options, Restricted Stock and Stock-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Jul. 14, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	15,952,814	15,077,409
Number of shares available for grant	252,053
Intrinsic value of stock options vested	$ 0	$ 0
Unrecognized compensation cost related to unvested stock options	$ 6,100,000	$ 7,600,000
Stock-based awards are expected to be recognized over a weighted average period	2 years 4 months 24 days	2 years 5 months 1 day
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate fair value of awards that vested	$ 500,000	$ 0
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period	4 years
Share-based compensation arrangement by share-based payment award, expiration period	10 years
Number of shares available for grant	0
Stock options exercised	306,518
Exercise price per share	$ 1.46
Common stock held by option holder in consideration of aggregate exercise price	122,608
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance			5,321,447

Stock Options, Restricted Sto_4

Stock Options, Restricted Stock and Stock-Based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Number Of Stock Options, Shares Outstanding	5,645,420
Number Of Stock Options, Shares, Granted	1,313,203
Number Of Stock Options, Shares, Cancelled, forfeited or expired	(1,292,002)
Number Of Stock Options, Shares Outstanding	5,666,621	5,645,420
Exercisable as of December 31, 2023	3,656,582
Unvested as of December 31, 2023	2,010,039
Weighted-Average Exercise Price, Outstanding	$ 2.77
Weighted-Average Exercise Price, Granted	1.3
Weighted-Average Exercise Price, Cancelled, forfeited or expired	2.6
Weighted-Average Exercise Price, Outstanding	2.47	$ 2.77
Exercisable as of December 31, 2023	2.49
Unvested as of December 31, 2023	$ 2.44
Weighted- Average Remaining Contractual Term (In Years), Outstanding	6 years 7 months 9 days	7 years 8 months 23 days
Exercisable as of December 31, 2023	5 years 6 months 18 days
Unvested as of December 31, 2023	8 years 6 months 14 days
Aggregate Intrinsic Value, Outstanding	$ 199
Exercisable as of December 31, 2023	26
Unvested as of December 31, 2023	$ 173

Stock Options, Restricted Sto_5

Stock Options, Restricted Stock and Stock-Based Compensation - Schedule of Fair Value of Stock Options Granted Was Estimated on Black-Scholes Options (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0%	0%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)	5 years 5 months 23 days	5 years 3 months 29 days
Risk-free interest rate	3.50%	1.69%
Expected volatility	91.33%	85.09%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)	6 years 29 days	6 years 29 days
Risk-free interest rate	4.86%	4.23%
Expected volatility	94.51%	87.67%

Stock Options, Restricted Sto_6

Stock Options, Restricted Stock and Stock-Based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock Units	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares Options, Unvested \| shares	612,366
Number of Shares Options, Granted \| shares	2,242,509
Number of Shares Options, Vested \| shares	(306,185)
Number of Shares Options, Forfeited \| shares	(22,258)
Number of Shares Options, Unvested \| shares	2,526,432
Weighted-Average Grant Date Fair Value, Unvested \| $ / shares	$ 1.71
Weighted-Average Grant Date Fair Value, Granted \| $ / shares	0.98
Weighted-Average Grant Date Fair Value, Vested \| $ / shares	1.71
Weighted-Average Grant Date Fair Value, Forfeited \| $ / shares	1.71
Weighted-Average Grant Date Fair Value, Unvested \| $ / shares	$ 1.06

Stock Options, Restricted Sto_7

Stock Options, Restricted Stock and Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation expense	$ 3,091	$ 2,307
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation expense	1,347	774
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock based compensation expense	$ 1,744	$ 1,533

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income at US statutory rate	21%	21%
Permanent adjustments	(1.30%)	(2.80%)
Mark to market	0.50%	18.30%
State taxes, net of federal benefit	6.90%	12.80%
Valuation allowance	(30.00%)	(56.90%)
Tax credits	2.90%	7.60%
Effective income tax rate	0%	0%

Income Taxes - Schedule of Net

Income Taxes - Schedule of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating losses	$ 23,136	$ 17,748
Intangibles	506	572
Accrued expenses & other	434	601
Deferred revenue	0	0
Lease liability	406	524
Stock compensation	1,168	863
Capitalized R&D expenditures	9,200	4,931
Credits	6,199	4,755
Total deferred tax assets	41,049	29,994
Valuation allowance	(40,548)	(29,166)	$ (18,493)
Net deferred tax assets	501	828
Deferred tax liabilities:
Right of use asset	(223)	(284)
Other	(278)	(544)
Total deferred tax liabilities	(501)	(828)
Net deferred tax assets (liabilities)	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
Income Taxes - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Income tax expense (benefit)	$ 0	$ 0
Income tax examination, description	The federal and state tax returns are generally subject to examination for the years ended December 31, 2014 through December 31, 2023. There are currently no pending tax examinations
Federal
Income Taxes [Line Items]
Operating loss carryforwards	$ 86,200,000
Operating loss carryforwards indefinite	$ 77,400,000
Operating loss carryforwards, begin to expire year	2027
Tax credit carryforward	$ 4,500,000
Tax credit carryforward, begin to expire year	2036
State
Income Taxes [Line Items]
Operating loss carryforwards	$ 79,600,000
Operating loss carryforwards, begin to expire year	2032
Tax credit carryforward	$ 2,200,000
Tax credit carryforward, begin to expire year	2030

Income Taxes - Summary of Chang

Income Taxes - Summary of Changes in Valuation Allowance for Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Valuation allowance	$ 29,166	$ 18,493
Increases recorded to income tax provision	11,382	10,673
Decreases recorded to income tax provision	0	0
Valuation allowance	$ 40,548	$ 29,166

Exclusive Licensing Agreement_2

Exclusive Licensing Agreement with a Related Party - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development service revenue, related party		$ 125
Exclusive Licensing Agreement \| Ventagen
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment from related party	$ 1,000
Future payment made upon the achievement of sales	$ 5,000
Commercial purposes at a price of cost plus percentage	25%
Upfront license fee		$ 1,000
Exclusive Licensing Agreement \| Ventagen \| Voting Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Related party transactions, ownership percentage	49.50%
Exclusive Licensing Agreement \| Ventagen \| Founders \| Voting Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Related party transactions, ownership percentage	47%
Exclusive Licensing Agreement \| Ventagen \| Related Party
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Due from related parties	$ 2,500
Related party costs	$ 4,000

Technology License Agreement -

Technology License Agreement - Additional Information (Details) - BWH License - USD ($)			12 Months Ended
	Sep. 15, 2020	Jan. 20, 2018	Dec. 31, 2023	Dec. 31, 2022
Technology License Agreement [Line Items]
Committed amount to remitting in support of clinical trial		$ 800,000
Committed period to remitting in support of clinical trial		3 years
Non-refundable fee		$ 40,000
Expense for startup and patient fees for clinical trials			$ 0	$ 0
Payment for license fee	$ 100,000
Payment at the time of entering into license	100,000
Payment for annual license fee	50,000
Maximum amount upon achievement of various clinical, commercial and sales milestones	$ 39,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Office space noncancelable operating lease expiration date	2026
Loss related to indemnification obligations	$ 0

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (37,939)	$ (18,794)
Denominator:
Weighted-average shares of common stock outstanding - basic	28,935,289	28,823,480
Weighted-average shares of common stock outstanding - diluted	28,935,289	28,823,480
Net loss per share - basic	$ (1.31)	$ (0.65)
Net loss per share - diluted	$ (1.31)	$ (0.65)

Net Loss Per Share - Schedule_2

Net Loss Per Share - Schedule of Potential Shares of Common Stock Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	15,700,761	13,765,494
Outstanding Warrants For Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	7,507,708	7,507,708
Outstanding Stock Options (As Converted To Common Stock)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	5,666,621	5,645,420
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share	2,526,432	612,366

Corporate Restructuring - Addit

Corporate Restructuring - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2023	Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]
Percentage of reduction in workforce positions	45%
Severance cost	$ 700,000
Restructuring costs		$ 700,000
Unpaid severance costs		46,000
Employee Severance
Restructuring Cost and Reserve [Line Items]
Payment related to restructuring plan		700,000
Research and Development
Restructuring Cost and Reserve [Line Items]
Restructuring costs		500,000
General and Administrative Expense
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 200,000