| Note 1 - Reporting Entity | 12 Months Ended | |||
|---|---|---|---|---|
| Dec. 31, 2019 | ||||
| Notes to Financial Statements | ||||
| Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] | 
 Aptose Biosciences Inc. (“Aptose” or the “Company”) is a clinical-stage biotechnology company committed to discovering and developing personalized therapies addressing unmet medical needs in oncology. The Company’s executive office is located in San Diego, California and its corporate office is located in Toronto, Canada. Aptose has  twoclinical-stage programs and a thirdprogram that is discovery-stage and partnered with another company. CG026806(“CG- 806”), Aptose’s mutation-agnostic FMS-like tyrosine kinase 3( FLT3/ Bruton’s tyrosine kinase (BTK) inhibitor, is currently enrolling patients in a Phase 1a/b,multicenter, open label, dose-escalation study with expansions to assess the safety, tolerability, PK, and preliminary efficacy of CG- 806in patients with chronic lymphocytic leukemia (CLL/SLL) or non-Hodgkin lymphomas (NHL). Aptose plans to seek allowance from the FDA to move into patient populations that include relapsed or refractory acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) in a separate Phase 1trial. APTO- 253,Aptose’s secondprogram, is a small molecule MYC inhibitor and is currently enrolling patients in a Phase 1bclinical trial for the treatment of patients with R/R blood cancers, including AML and high-risk Myelodysplastic Syndrome. Since our inception, we have financed our operations and technology acquisitions primarily from equity financing, proceeds from the exercise of warrants and stock options, and interest income on funds held for future investment. Our uses of cash for operating activities have primarily consisted of salaries and wages for our employees, facility and facility-related costs for our offices and laboratories, fees paid in connection with preclinical and clinical studies, drug manufacturing costs, laboratory supplies and materials, and professional fees. During the year ended   December 31, 2019, the Company completed twoconfidentially marketed public offering (CMPO) through the issuance of 30,043,750common shares for gross proceeds of $95.45million (approximately $88.18million net of share issue costs). The Company also raised capital pursuant to twoseparate share purchase agreement with Aspire Capital (Aspire) through the issuance of 7,302,433common shares for gross and net proceeds of $14.4 We do  notexpect to generate positive cash flow from operations for the foreseeable future due to the early stage of our clinical trials. It is expected that negative cash flow will continue until such time, if ever, that we receive regulatory approval to commercialize any of our products under development and/or royalty or milestone revenue from any such products exceeds expenses. We believe that our cash, cash equivalents and investments on hand at   December 31, 2019 will be sufficient to finance our operations for at least 12months from the issuance date of these financial statements.  We have based these estimates on assumptions and plans which  may change and which could impact the magnitude and/or timing of operating expenses and our cash runway. These estimates include the rate of enrolment and timing and release of the results of our clinical trials, and our reliance on our manufacturers. We expect that we will need to raise additional capital or incur indebtedness to continue to fund our operations in the future. Our ability to raise additional funds could be affected by adverse market conditions, the status of our product pipeline and various other factors and we   may be unable to raise capital when needed, or on terms favorable to us. If necessary funds are notavailable, we  may have to delay, reduce the scope of, or eliminate some of our development programs, potentially delaying the time to market for any of our product candidates. |