Description of Business, Organization and Liquidity	12 Months Ended
Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Organization and Liquidity	1. Description of Business, Organization and Liquidity Business IO Biotech, Inc. is a clinical-stage biotechnology company dedicated to the identification and development of disruptive immune therapies for the treatment of cancer. As used in these financial statements, unless the context otherwise requires, references to the “Company”, “we,” “us,” and “our” refer to IO Biotech, Inc. and its subsidiaries. IO Biotech ApS was incorporated in Denmark in December 2014. We are developing novel, immune-modulating cancer vaccines based on our T-win technology platform. Corporate reorganization In November 2021, we completed a corporate reorganization whereby IO Biotech ApS became a wholly-owned subsidiary of the Company. In connection with the corporate reorganization, each issued and outstanding Class A ordinary share ($0.16 par value) was exchanged on a one for one basis into shares of common stock of the Company ($0.001 par value). Each Class B and Class C preference share of IO Biotech ApS was exchanged on a one for one basis into shares of Class B and Class C preferred stock of the Company. Initial Public Offering ("IPO") In November 2021, we completed our IPO, selling an aggregate of 8,222,500 shares of common stock at a price to the public of $14.00 per share, including 1,072,500 shares of common stock sold pursuant to the underwriters’ exercise of their option to purchase additional shares of common stock. We received net proceeds from the IPO, after deducting underwriting discounts and commissions and other offering costs, of approximately $103.3 million. Immediately prior to the consummation of the IPO, all outstanding shares of our class A ordinary shares and class B and class C convertible preference shares were converted into 20,592,413 shares of common stock. Upon the closing of the IPO on November 9, 2021, a total of 28,815,267 shares of common stock were outstanding. Our common stock began trading on the Nasdaq Global Market on November 5, 2021 under the symbol “IOBT”. On November 9, 2021, we amended and restated the certificate of incorporation of IO Biotech, Inc. to authorize 300,000,000 shares of common stock and 5,000,000 shares of preferred stock. The shares of preferred stock are currently undesignated. Risks and Uncertainties We are subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities. Our product candidates are in development. There can be no assurance that our research and development will be successfully completed, that adequate protection for our intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if our product development efforts are successful, it is uncertain when, if ever, we will generate significant revenue from product sales. We operate in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, we are dependent upon the services of our employees and consultants. Liquidity Considerations and Going Concern Basis of Accounting Since inception, we have devoted substantially all our efforts to business planning, conducting research and development, recruiting management and technical staff, and raising capital. We have financed our operations primarily through the issuance of convertible preference shares, convertible notes and, most recently, our IPO. Our continued discovery and development of product candidates will require significant additional research and development efforts, including extensive 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 product development efforts are successful, it is uncertain when, if ever, we will realize significant revenue from product sales. As of December 31, 2022, we had an accumulated deficit of $177.7 million. We have incurred losses and negative cash flows from operations since inception, including net losses of $71.5 million and $67.9 million for the years ended December 31, 2022 and 2021, respectively. We expect that our operating losses and negative cash flows will continue for the foreseeable future as we continue to develop our product candidates. We currently expect that our cash and cash equivalents of $142.6 million as of December 31, 2022 will be sufficient to fund our operating expenses and capital requirements for at least 12 months from the date the financial statements are issued. On this basis the financial statements are prepared on a going concern basis of accounting. However, additional funding will be necessary to fund future discovery research, pre-clinical and clinical activities. We will seek additional funding through public financings, debt financings, collaboration agreements, strategic alliances and licensing arrangements. Although we have been successful in raising capital in the past, there is no assurance that we will be successful in obtaining such additional financing on acceptable terms, or at all, and we may not be able to enter into collaborations or other arrangements. If we are unable to obtain funding, we could be forced to delay, reduce or eliminate our research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect our business prospects, even our ability to continue operations. Coronavirus Pandemic In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. In order to mitigate the spread of COVID-19, governments have imposed unprecedented restrictions on business operations, travel and gatherings, resulting in a global economic downturn and other adverse economic and societal impacts. The COVID-19 pandemic has also overwhelmed or otherwise led to changes in the operations of many healthcare facilities, including clinical trial sites. We cannot predict the scope and severity of any further disruptions as a result of COVID-19 and continuing resource constraints or their impacts on CROs, us, clinical trial sites and others. But continuing resource constraints or business disruptions for us or any of the third parties with whom we engage, including the collaborators, contract organizations, third-party manufacturers, suppliers, clinical trial sites, regulators and other third parties with whom we conduct business could materially and negatively impact our ability to conduct our business in the manner and on the timelines presently planned. The actual and perceived impact of the COVID-19 pandemic is changing daily, and its ultimate effect on our business cannot be predicted. As a result, there can be no assurance that we will not experience additional negative impacts associated with COVID-19, which could be significant. The COVID-19 pandemic may negatively impact our business, financial condition and results of operations causing interruptions or delays in the Company’s programs and services.

Description of Business, Organization and Liquidity

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business, Organization and Liquidity

1. Description of Business, Organization and Liquidity

Business

IO Biotech, Inc. is a clinical-stage biotechnology company dedicated to the identification and development of disruptive immune therapies for the treatment of cancer. As used in these financial statements, unless the context otherwise requires, references to the “Company”, “we,” “us,” and “our” refer to IO Biotech, Inc. and its subsidiaries. IO Biotech ApS was incorporated in Denmark in December 2014. We are developing novel, immune-modulating cancer vaccines based on our T-win technology platform.

Corporate reorganization

In November 2021, we completed a corporate reorganization whereby IO Biotech ApS became a wholly-owned subsidiary of the Company. In connection with the corporate reorganization, each issued and outstanding Class A ordinary share ($0.16 par value) was exchanged on a one for one basis into shares of common stock of the Company ($0.001 par value). Each Class B and Class C preference share of IO Biotech ApS was exchanged on a one for one basis into shares of Class B and Class C preferred stock of the Company.

Initial Public Offering ("IPO")

In November 2021, we completed our IPO, selling an aggregate of 8,222,500 shares of common stock at a price to the public of $14.00 per share, including 1,072,500 shares of common stock sold pursuant to the underwriters’ exercise of their option to purchase additional shares of common stock. We received net proceeds from the IPO, after deducting underwriting discounts and commissions and other offering costs, of approximately $103.3 million.

Immediately prior to the consummation of the IPO, all outstanding shares of our class A ordinary shares and class B and class C convertible preference shares were converted into 20,592,413 shares of common stock. Upon the closing of the IPO on November 9, 2021, a total of 28,815,267 shares of common stock were outstanding. Our common stock began trading on the Nasdaq Global Market on November 5, 2021 under the symbol “IOBT”.

On November 9, 2021, we amended and restated the certificate of incorporation of IO Biotech, Inc. to authorize 300,000,000 shares of common stock and 5,000,000 shares of preferred stock. The shares of preferred stock are currently undesignated.

Risks and Uncertainties

We are subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities.

Our product candidates are in development. There can be no assurance that our research and development will be successfully completed, that adequate protection for our intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if our product development efforts are successful, it is uncertain when, if ever, we will generate significant revenue from product sales. We operate in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, we are dependent upon the services of our employees and consultants.

Liquidity Considerations and Going Concern Basis of Accounting

Since inception, we have devoted substantially all our efforts to business planning, conducting research and development, recruiting management and technical staff, and raising capital. We have financed our operations primarily through the issuance of convertible preference shares, convertible notes and, most recently, our IPO.

Our continued discovery and development of product candidates will require significant additional research and development efforts, including extensive 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 product development efforts are successful, it is uncertain when, if ever, we will realize significant revenue from product sales.

As of December 31, 2022, we had an accumulated deficit of $177.7 million. We have incurred losses and negative cash flows from operations since inception, including net losses of $71.5 million and $67.9 million for the years ended December 31, 2022 and 2021, respectively. We expect that our operating losses and negative cash flows will continue for the foreseeable future as we continue to develop our product candidates. We currently expect that our cash and cash equivalents of $142.6 million as of December 31, 2022 will be sufficient to fund our operating expenses and capital requirements for at least 12 months from the date the financial statements are issued. On this basis the financial statements are prepared on a going concern basis of accounting. However, additional funding will be necessary to fund future discovery research, pre-clinical and clinical activities. We will seek additional funding through public financings, debt financings, collaboration agreements, strategic alliances and licensing arrangements. Although we have been successful in raising capital in the past, there is no assurance that we will be successful in obtaining such additional financing on acceptable terms, or at all, and we may not be able to enter into collaborations or other arrangements. If we are unable to obtain funding, we could be forced to delay, reduce or eliminate our research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect our business prospects, even our ability to continue operations.

Coronavirus Pandemic

In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. In order to mitigate the spread of COVID-19, governments have imposed unprecedented restrictions on business operations, travel and gatherings, resulting in a global economic downturn and other adverse economic and societal impacts. The COVID-19 pandemic has also overwhelmed or otherwise led to changes in the operations of many healthcare facilities, including clinical trial sites. We cannot predict the scope and severity of any further disruptions as a result of COVID-19 and continuing resource constraints or their impacts on CROs, us, clinical trial sites and others. But continuing resource constraints or business disruptions for us or any of the third parties with whom we engage, including the collaborators, contract organizations, third-party manufacturers, suppliers, clinical trial sites, regulators and other third parties with whom we conduct business could materially and negatively impact our ability to conduct our business in the manner and on the timelines presently planned.

The actual and perceived impact of the COVID-19 pandemic is changing daily, and its ultimate effect on our business cannot be predicted. As a result, there can be no assurance that we will not experience additional negative impacts associated with COVID-19, which could be significant. The COVID-19 pandemic may negatively impact our business, financial condition and results of operations causing interruptions or delays in the Company’s programs and services.