| Cover Page - USD ($) | 12 Months Ended | | |
| Dec. 31, 2023 | Mar. 15, 2024 | Jun. 30, 2023 |
| Document Information [Line Items] | | | |
| Document Type | 10-K/A | | |
| Amendment Flag | true | | |
| Amendment Description | EXPLANATORY NOTE This Amendment No. 2 (this “Amendment”) amends the Annual Report on Form 10-K for the year ended December 31, 2023 of XBiotech, Inc. (the “Company”), filed with the Securities and Exchange Commission (the “SEC”) on March 15, 2024 (as amended on April 24, 2024, the “Original Form 10-K”), for the purpose of amending and restating in its entirety Part III, Item 10 of the Original Form 10-K in order to correct certain information on directors provided therein. Except as described above, no other changes have been made to the Original Form 10-K. The Original Form 10-K continues to speak as of the dates described in the Original Form 10-K, and we have not updated the disclosures contained therein to reflect any events that occurred subsequent to such dates. Accordingly, this Amendment should be read in conjunction with the Company’s filings made with the SEC subsequent to the filing of the Original Form 10-K, as information in such filings may update or supersede certain information contained in this Amendment. | | |
| Document Annual Report | true | | |
| Document Transition Report | false | | |
| Entity File Number | 001-37347 | | |
| Entity Registrant Name | XBiotech Inc. | | |
| Document Period End Date | Dec. 31, 2023 | | |
| Entity Central Index Key | 0001626878 | | |
| Current Fiscal Year End Date | --12-31 | | |
| Document Fiscal Year Focus | 2023 | | |
| Document Fiscal Period Focus | FY | | |
| Entity Incorporation, State or Country Code | A1 | | |
| Entity Tax Identification Number | 00-0000000 | | |
| Entity Address, Address Line One | 5217 Winnebago Ln | | |
| Entity Address, City or Town | Austin | | |
| Entity Address, State or Province | TX | | |
| Entity Address, Postal Zip Code | 78744 | | |
| City Area Code | 512 | | |
| Local Phone Number | 386-2900 | | |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share | | |
| Trading Symbol | XBIT | | |
| Security Exchange Name | NASDAQ | | |
| Entity Well-known Seasoned Issuer | No | | |
| Entity Voluntary Filers | No | | |
| Entity Current Reporting Status | Yes | | |
| Entity Interactive Data Current | Yes | | |
| Entity Small Business | true | | |
| Entity Filer Category | Non-accelerated Filer | | |
| Entity Emerging Growth Company | false | | |
| ICFR Auditor Attestation Flag | false | | |
| Document Financial Statement Error Correction [Flag] | false | | |
| Entity Shell Company | false | | |
| Entity Public Float | | | $ 140,476,818 |
| Entity Common Stock, Shares Outstanding | | 30,450,881 | |
| Auditor Name | Whitley Pann LLP | | |
| Auditor Firm ID | 726 | | |
| Auditor Location | Austin, Texas | | |
