v3.26.1
Document And Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Mar. 31, 2026
Jun. 28, 2024
Cover [Abstract]        
Entity Central Index Key 0000882361      
Entity Registrant Name Aptose Biosciences Inc.      
Amendment Flag false      
Current Fiscal Year End Date --12-31      
Document Fiscal Period Focus FY      
Document Fiscal Year Focus 2025      
Document Type 10-K      
Document Annual Report true      
Document Period End Date Dec. 31, 2025      
Document Transition Report false      
Securities Act File Number 001-32001      
Entity Incorporation, State or Country Code Z4      
Entity Tax Identification Number 98-1136802      
Entity Address, Address Line One 66 Wellington Street WestSuite 5300      
Entity Address, Address Line Two TD Bank Tower Box 48      
Entity Address, City or Town Toronto      
Entity Address, State or Province ON      
Entity Address, Postal Zip Code M5K 1E6      
City Area Code 647      
Local Phone Number 479-9828      
Entity Well-known Seasoned Issuer No      
Entity Voluntary Filers No      
Entity Current Reporting Status Yes      
Entity Interactive Data Current Yes      
Entity Filer Category Non-accelerated Filer      
Entity Small Business true      
Entity Emerging Growth Company false      
ICFR Auditor Attestation Flag false      
Document Financial Statement Error Correction [Flag] false      
Entity Shell Company false      
Entity Public Float       $ 22,075,799
Entity Common Stock, Shares Outstanding     2,552,429  
Documents Incorporated by Reference [Text Block]

DOCUMENTS INCORPORATED BY REFERENCE

      
Auditor Opinion [Text Block]

Opinion on the Financial Statements

We have audited the accompanying consolidated statement of financial position of Aptose Biosciences Inc. (the Company) as of December 31, 2025, and the related consolidated statements of loss and comprehensive loss, changes in shareholders’ deficit and cash flows for the year ended December 31, 2025, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025, and the results of its operations and its cash flows for the year ended December 31, 2025, in conformity with U.S. generally accepted accounting principles.

      
Auditor Name Ernst & Young LLP KPMG LLP    
Auditor Location Toronto, Canada Vaughan, Canada    
Auditor Firm ID 1263 85