Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (67,879)	$ (12,042)
Adjustment to reconcile net loss to net cash used in operating activities
Equity-based compensation	1,791	64
Fair value adjustments on preference shares tranche obligations	26,535
Fair value adjustments convertible notes		1,985
Other non-cash items, net	(317)	(111)
Changes in operating assets and liabilities
Prepaid expenses and other assets	(8,090)	(672)
Accounts payable	3,406	(475)
Accrued expenses and other current liabilities	3,908	1,295
Net cash used in operating activities	(40,646)	(9,956)
Cash flows from investing activities
Purchase of property and equipment	(153)
Net cash used in investing activities	(153)
Cash flows from financing activities
Proceeds from issuance of preference shares	149,941	5,116
Proceeds from issuance of common stock	115,115
Net cash provided by financing activities	252,951	5,102
Net increase (decrease) in cash and cash equivalents	212,152	(4,854)
Effect of exchange rate changes on cash and cash equivalents	(3,758)	413
Cash and cash equivalents, beginning of period	3,405	7,846
Cash and cash equivalents, end of period	211,799	3,405
Components of cash, cash equivalents, and restricted cash
Cash and cash equivalents	211,531	3,405
Restricted cash	268
Supplemental disclosures of non-cash financing activities:
Exchange of preferred and ordinary shares of IO Biotech ApS into common stock of IO Biotech, Inc. upon closing of initial public offering	213,443
Non-cash portion of settlement of preference shares tranche obligation	25,908
Exchange of convertible notes for class B preference shares		10,277
Preferred Stock
Cash flows from financing activities
Issuance costs	(340)	$ (14)
Common Stock
Cash flows from financing activities
Issuance costs	$ (11,765)