3.25.4 html 82 277 1 false 31 0 false 4 false false R1.htm 000 - Document - Document And Entity Information Sheet http://xbiotech.com/20251231/role/statement-document-and-entity-information Document And Entity Information Cover 1 false false R2.htm 001 - Statement - Consolidated Balance Sheets Sheet http://xbiotech.com/20251231/role/statement-consolidated-balance-sheets Consolidated Balance Sheets Statements 2 false false R3.htm 002 - Statement - Consolidated Balance Sheets (Parentheticals) Sheet http://xbiotech.com/20251231/role/statement-consolidated-balance-sheets-parentheticals Consolidated Balance Sheets (Parentheticals) Statements 3 false false R4.htm 003 - Statement - Consolidated Statements of Operations Sheet http://xbiotech.com/20251231/role/statement-consolidated-statements-of-operations Consolidated Statements of Operations Statements 4 false false R5.htm 004 - Statement - Consolidated Statements of Shareholders' Equity Sheet http://xbiotech.com/20251231/role/statement-consolidated-statements-of-shareholders-equity Consolidated Statements of Shareholders' Equity Statements 5 false false R6.htm 005 - Statement - Consolidated Statements of Cash Flows Sheet http://xbiotech.com/20251231/role/statement-consolidated-statements-of-cash-flows Consolidated Statements of Cash Flows Statements 6 false false R7.htm 995443 - Disclosure - Award Timing Disclosure Sheet http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure Award Timing Disclosure Notes 7 false false R8.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 8 false false R9.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 9 false false R10.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 10 false false R11.htm 995550 - Disclosure - Note 1 - Organization Sheet http://xbiotech.com/20251231/role/statement-note-1-organization Note 1 - Organization Notes 11 false false R12.htm 995551 - Disclosure - Note 2 - Significant Accounting Policies Sheet http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies Note 2 - Significant Accounting Policies Notes 12 false false R13.htm 995552 - Disclosure - Note 3 - Property and Equipment and Building Construction in Progress Sheet http://xbiotech.com/20251231/role/statement-note-3-property-and-equipment-and-building-construction-in-progress Note 3 - Property and Equipment and Building Construction in Progress Notes 13 false false R14.htm 995553 - Disclosure - Note 4 - Accrued Expenses Sheet http://xbiotech.com/20251231/role/statement-note-4-accrued-expenses Note 4 - Accrued Expenses Notes 14 false false R15.htm 995554 - Disclosure - Note 5 - Convertible Loan, Related Party Sheet http://xbiotech.com/20251231/role/statement-note-5-convertible-loan-related-party Note 5 - Convertible Loan, Related Party Notes 15 false false R16.htm 995555 - Disclosure - Note 6 - Common Stock Sheet http://xbiotech.com/20251231/role/statement-note-6-common-stock Note 6 - Common Stock Notes 16 false false R17.htm 995556 - Disclosure - Note 7 - Common Stock Options Sheet http://xbiotech.com/20251231/role/statement-note-7-common-stock-options Note 7 - Common Stock Options Notes 17 false false R18.htm 995557 - Disclosure - Note 8 - Net Loss Per Share Sheet http://xbiotech.com/20251231/role/statement-note-8-net-loss-per-share Note 8 - Net Loss Per Share Notes 18 false false R19.htm 995558 - Disclosure - Note 9 - Income Taxes Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes Note 9 - Income Taxes Notes 19 false false R20.htm 995559 - Disclosure - Significant Accounting Policies (Policies) Sheet http://xbiotech.com/20251231/role/statement-significant-accounting-policies-policies Significant Accounting Policies (Policies) Policies http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies 20 false false R21.htm 995560 - Disclosure - Note 2 - Significant Accounting Policies (Tables) Sheet http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies-tables Note 2 - Significant Accounting Policies (Tables) Tables http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies 21 false false R22.htm 995561 - Disclosure - Note 3 - Property and Equipment and Building Construction in Progress (Tables) Sheet http://xbiotech.com/20251231/role/statement-note-3-property-and-equipment-and-building-construction-in-progress-tables Note 3 - Property and Equipment and Building Construction in Progress (Tables) Tables http://xbiotech.com/20251231/role/statement-note-3-property-and-equipment-and-building-construction-in-progress 22 false false R23.htm 995562 - Disclosure - Note 4 - Accrued Expenses (Tables) Sheet http://xbiotech.com/20251231/role/statement-note-4-accrued-expenses-tables Note 4 - Accrued Expenses (Tables) Tables http://xbiotech.com/20251231/role/statement-note-4-accrued-expenses 23 false false R24.htm 995563 - Disclosure - Note 7 - Common Stock Options (Tables) Sheet http://xbiotech.com/20251231/role/statement-note-7-common-stock-options-tables Note 7 - Common Stock Options (Tables) Tables http://xbiotech.com/20251231/role/statement-note-7-common-stock-options 24 false false R25.htm 995564 - Disclosure - Note 8 - Net Loss Per Share (Tables) Sheet http://xbiotech.com/20251231/role/statement-note-8-net-loss-per-share-tables Note 8 - Net Loss Per Share (Tables) Tables http://xbiotech.com/20251231/role/statement-note-8-net-loss-per-share 25 false false R26.htm 995565 - Disclosure - Note 9 - Income Taxes (Tables) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-tables Note 9 - Income Taxes (Tables) Tables http://xbiotech.com/20251231/role/statement-note-9-income-taxes 26 false false R27.htm 995566 - Disclosure - Note 1 - Organization (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-1-organization-details-textual Note 1 - Organization (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-1-organization 27 false false R28.htm 995567 - Disclosure - Note 2 - Significant Accounting Policies (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies-details-textual Note 2 - Significant Accounting Policies (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies-tables 28 false false R29.htm 995568 - Disclosure - Note 2 - Significant Accounting Policies - Share-based Compensation Expense (Details) Sheet http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies-sharebased-compensation-expense-details Note 2 - Significant Accounting Policies - Share-based Compensation Expense (Details) Details 29 false false R30.htm 995569 - Disclosure - Note 2 - Significant Accounting Policies - Stock Option Valuation Assumptions (Details) Sheet http://xbiotech.com/20251231/role/statement-note-2-significant-accounting-policies-stock-option-valuation-assumptions-details Note 2 - Significant Accounting Policies - Stock Option Valuation Assumptions (Details) Details 30 false false R31.htm 995570 - Disclosure - Note 3 - Property and Equipment and Building Construction in Progress (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-3-property-and-equipment-and-building-construction-in-progress-details-textual Note 3 - Property and Equipment and Building Construction in Progress (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-3-property-and-equipment-and-building-construction-in-progress-tables 31 false false R32.htm 995571 - Disclosure - Note 3 - Property and Equipment and Building Construction in Progress - Property and Equipment, Net (Details) Sheet http://xbiotech.com/20251231/role/statement-note-3-property-and-equipment-and-building-construction-in-progress-property-and-equipment-net-details Note 3 - Property and Equipment and Building Construction in Progress - Property and Equipment, Net (Details) Details 32 false false R33.htm 995572 - Disclosure - Note 4 - Accrued Expenses - Accrued Expenses (Details) Sheet http://xbiotech.com/20251231/role/statement-note-4-accrued-expenses-accrued-expenses-details Note 4 - Accrued Expenses - Accrued Expenses (Details) Details 33 false false R34.htm 995573 - Disclosure - Note 5 - Convertible Loan, Related Party (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-5-convertible-loan-related-party-details-textual Note 5 - Convertible Loan, Related Party (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-5-convertible-loan-related-party 34 false false R35.htm 995574 - Disclosure - Note 6 - Common Stock (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-6-common-stock-details-textual Note 6 - Common Stock (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-6-common-stock 35 false false R36.htm 995575 - Disclosure - Note 7 - Common Stock Options (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-7-common-stock-options-details-textual Note 7 - Common Stock Options (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-7-common-stock-options-tables 36 false false R37.htm 995576 - Disclosure - Note 7 - Common Stock Options - Changes in Common Stock Options Issued (Details) Sheet http://xbiotech.com/20251231/role/statement-note-7-common-stock-options-changes-in-common-stock-options-issued-details Note 7 - Common Stock Options - Changes in Common Stock Options Issued (Details) Details 37 false false R38.htm 995577 - Disclosure - Note 7 - Common Stock Options - Changes in Nonvested Options (Details) Sheet http://xbiotech.com/20251231/role/statement-note-7-common-stock-options-changes-in-nonvested-options-details Note 7 - Common Stock Options - Changes in Nonvested Options (Details) Details 38 false false R39.htm 995578 - Disclosure - Note 8 - Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) Sheet http://xbiotech.com/20251231/role/statement-note-8-net-loss-per-share-computation-of-basic-and-diluted-net-loss-per-share-details Note 8 - Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) Details 39 false false R40.htm 995579 - Disclosure - Note 9 - Income Taxes (Details Textual) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-details-textual Note 9 - Income Taxes (Details Textual) Details http://xbiotech.com/20251231/role/statement-note-9-income-taxes-tables 40 false false R41.htm 995580 - Disclosure - Note 9 - Income Taxes - Components of Income Before Income Taxes (Details) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-components-of-income-before-income-taxes-details Note 9 - Income Taxes - Components of Income Before Income Taxes (Details) Details 41 false false R42.htm 995581 - Disclosure - Note 9 - Income Taxes - Income Tax from Continuing Operations (Details) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-income-tax-from-continuing-operations-details Note 9 - Income Taxes - Income Tax from Continuing Operations (Details) Details 42 false false R43.htm 995582 - Disclosure - Note 9 - Income Taxes - Effective Income Tax Rate Reconciliation (Details) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-effective-income-tax-rate-reconciliation-details Note 9 - Income Taxes - Effective Income Tax Rate Reconciliation (Details) Details 43 false false R44.htm 995583 - Disclosure - Note 9 - Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-significant-components-of-deferred-tax-assets-and-liabilities-details Note 9 - Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) Details 44 false false R45.htm 995584 - Disclosure - Note 9 - Income Taxes - Reconciliation of Unrecognized Tax Benefit Balances (Details) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-reconciliation-of-unrecognized-tax-benefit-balances-details Note 9 - Income Taxes - Reconciliation of Unrecognized Tax Benefit Balances (Details) Details 45 false false R46.htm 995585 - Disclosure - Note 9 - Income Taxes - Schedule of Income Taxes Paid (Details) Sheet http://xbiotech.com/20251231/role/statement-note-9-income-taxes-schedule-of-income-taxes-paid-details Note 9 - Income Taxes - Schedule of Income Taxes Paid (Details) Details 46 false false All Reports Book All Reports xbit-20251231.xsd xbit-20251231_cal.xml xbit-20251231_def.xml xbit-20251231_lab.xml xbit-20251231_pre.xml xbit20251231_10k.htm http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/cyd/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true