| Note 1 - Reporting Entity | 6 Months Ended | |||
|---|---|---|---|---|
| Jun. 30, 2020 | ||||
| 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 offices are located in San Diego, California and its head office is located in Toronto, Canada. Aptose has  twoclinical-stage programs and a secondprogram that is discovery-stage and partnered with another company. CG026806(“CG- 806”), Aptose's pan-FMS-like tyrosine kinase 3/ pan-Bruton's tyrosine kinase inhibitor, is currently enrolling patients in a Phase 1,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 was granted IND allowance from the U.S Food and Drug Administration (FDA) to initiate a separate Phase 1trial in patients with relapse or refractory acute myeloid leukemia (AML) in  June 2020. 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. We are advancing  first-in-class targeted agents to treat life-threatening cancers that, in most cases, are notelective for patients and require immediate treatment.  However, COVID- 19has caused global economic and social disruptions that could adversely affect our ongoing and planned research and development of our clinical-stage programs including but notlimited to drug manufacturing campaigns, clinical trial activities including enrollment of patients in our ongoing and planned clinical trials, collection and analysis of patient data and eventually, the reporting of results from our trials. 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. 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   June 30, 2020 will be sufficient to finance our operations for at least 12months from the issuance date of these financial statements. Our cash needs for the next twelvemonths include estimates of the number of patients and rate of enrollment of our clinical trials, the amount of drug product that we will require to support our clinical trials, and our general corporate overhead costs to support our operations, and our reliance on our manufacturers. 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. Our ability to raise additional funds could be affected by adverse market conditions, the status of our product pipeline, possible delays in enrollment in our trial related to COVID- 19,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. |