| Document and Entity Information | Nov. 21, 2024 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0000882361 |
| Document Type | 8-K |
| Document Period End Date | Nov. 21, 2024 |
| Entity Registrant Name | APTOSE BIOSCIENCES INC. |
| Entity Incorporation State Country Code | Z4 |
| Entity File Number | 001-32001 |
| Entity Tax Identification Number | 98-1136802 |
| Entity Address, Address Line One | 66 Wellington Street West, Suite 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 | (310) |
| Local Phone Number | 849-8060 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Shares, no par value |
| Trading Symbol | APTO |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
