Annual report pursuant to Section 13 and 15(d)

Document And Entity Information

Document And Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Mar. 12, 2019
Jun. 30, 2018
Document Information [Line Items]      
Entity Registrant Name Aptose Biosciences Inc.    
Entity Central Index Key 0000882361    
Trading Symbol apto    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer No    
Entity Emerging Growth Company true    
Entity Small Business true    
Entity Common Stock, Shares Outstanding (in shares)   40,249,112  
Entity Public Float     $ 134,370,583
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Shell Company false    
Entity Ex Transition Period true