Note 11 - Related party transactions (Details Textual) |
9 Months Ended | 47 Months Ended | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Nov. 12, 2025
USD ($)
|
Oct. 27, 2025
USD ($)
|
Oct. 17, 2025
USD ($)
|
Sep. 25, 2025
USD ($)
|
Jun. 18, 2025
USD ($)
Advance
|
Jun. 17, 2025
USD ($)
|
Mar. 18, 2025
USD ($)
$ / shares
shares
|
Sep. 02, 2024
USD ($)
|
Aug. 27, 2024
USD ($)
|
Jan. 30, 2024
USD ($)
$ / shares
shares
|
Sep. 06, 2023
USD ($)
shares
|
Nov. 04, 2021
USD ($)
shares
|
Sep. 30, 2025
USD ($)
$ / shares
shares
|
Sep. 30, 2024
USD ($)
|
Sep. 30, 2025
USD ($)
$ / shares
shares
|
Sep. 22, 2025
USD ($)
Advance
|
Dec. 31, 2024
USD ($)
shares
|
Aug. 10, 2023
USD ($)
|
|
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Common Stock, Shares Outstanding | shares | 2,552,429 | 2,552,429 | 2,006,028 | |||||||||||||||
| Warrants outstanding | shares | 1,267,585 | 1,267,585 | ||||||||||||||||
| Accrued liabilities | $ 4,804,000 | $ 4,804,000 | $ 2,773,000 | |||||||||||||||
| Accounts payable | 1,456,000 | 1,456,000 | 1,258,000 | |||||||||||||||
| Proceeds from loan payable with related parties | 10,350,000 | $ 10,000,000 | ||||||||||||||||
| Short-Term Advance from CEO [Member] | CEO [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Loan is repayable date | Jun. 17, 2025 | |||||||||||||||||
| Proceeds from loan payable with related parties | $ 100,000 | |||||||||||||||||
| Short-Term Advance | 0 | 0 | ||||||||||||||||
| Public Offering [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Common shares issued (in shares) | shares | 188,304 | |||||||||||||||||
| Over-Allotment Option [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Common shares issued upon exercise of stock options | $ 24,561 | |||||||||||||||||
| Shares Issued, Price Per Share | $ / shares | $ 51.3 | |||||||||||||||||
| Common Shares [Member] | Public Offering [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Warrants to purchase common shares, number of warrants | shares | 188,174 | |||||||||||||||||
| Supply Agreement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Expenses | 0 | 0 | 7,100,000 | |||||||||||||||
| Accrued liabilities | $ 0 | |||||||||||||||||
| Accounts payable | 0 | $ 0 | ||||||||||||||||
| Tuspetinib Licensing Agreement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| License Fee, Total | $ 12,500,000 | |||||||||||||||||
| Payments for License Fee | 5,000,000 | |||||||||||||||||
| Stock Issued During Period, Value, Licensing Fee | $ 7,500,000 | |||||||||||||||||
| Hanmi Loan Agreement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Loan agreement amount | $ 10,000,000 | |||||||||||||||||
| Loan is repayable date | Jan. 31, 2027 | |||||||||||||||||
| Interest expense | 400,000 | 100,000 | ||||||||||||||||
| Interest expense paid | 0 | $ 100,000 | ||||||||||||||||
| Loan interest rate | 6.00% | |||||||||||||||||
| Convertible debt conversion | $ 8,500,000 | |||||||||||||||||
| Hanmi Facility Agreement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Loan agreement amount | $ 8,500,000 | $ 11,900,000 | ||||||||||||||||
| Loan is repayable date | Jun. 18, 2025 | |||||||||||||||||
| Interest expense | 100,000 | |||||||||||||||||
| Interest expense paid | $ 0 | |||||||||||||||||
| Loan interest rate | 6.00% | 6.00% | ||||||||||||||||
| Maximum number of advances | Advance | 5 | 8 | ||||||||||||||||
| Maximum amount available under single advance | $ 2,500,000 | $ 2,000,000 | ||||||||||||||||
| Minimum amount available under single advance | $ 500,000 | |||||||||||||||||
| Initial proceeds from related party debt | $ 1,800,000 | |||||||||||||||||
| Proceeds from loan payable with related parties | $ 8,500,000 | |||||||||||||||||
| Repayment date | Aug. 31, 2028 | |||||||||||||||||
| Interest payments frequency | three-month | |||||||||||||||||
| Hanmi Facility Agreement [Member] | Subsequent Event [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Additional proceeds from related party debt | $ 1,200,000 | $ 1,200,000 | ||||||||||||||||
| Proceeds from loan payable with related parties | $ 4,200,000 | |||||||||||||||||
| Debt Conversion Agreement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Shares Issued, Price Per Share | $ / shares | $ 3.7 | |||||||||||||||||
| Debt conversion, description | Additionally, pursuant to the Debt Conversion Agreement, the Company and Hanmi agreed that the interest payment associated with the period from December 21, 2024 through March 31, 2025 (the "First Deferred Interest Period") may be deferred and made on or before the final closing date of a financing, not including the amount being converted pursuant to the Debt Conversion Agreement, totaling $15.0 million ("Capital Raise"), but no later than June 27, 2025. On June 24, 2025, the Company and Hanmi entered into an Interest Payment Agreement whereby the interest due for the First Deferred Interest Period and interest associated with the period from March 31, 2025 through June 30, 2025 (the "Second Deferred Interest Period") may be deferred and made no later than December 31, 2025. Further, pursuant to the Debt Conversion Agreement, Hanmi, at its sole discretion, can opt to convert the remaining indebtedness amount, or a portion thereof, to Aptose Common Shares upon the successful completion of the Capital Raise, provided that the amount of Aptose Common Shares delivered to Hanmi pursuant to such subsequent conversion shall not cause Hanmi to own more than 19.99% of the Company. Subsequently, pursuant to the Hanmi Facility Agreement, the maturity date for the Hanmi Loan Agreement was modified such that the outstanding principal amount and accrued and unpaid interest under the Hanmi Loan Agreement would be repayable on August 31, 2028 as discussed below. | |||||||||||||||||
| Capital raise, amount | $ 15,000,000 | |||||||||||||||||
| Convertiable debt amount | $ 1,500,000 | |||||||||||||||||
| Common shares converted | shares | 409,063 | |||||||||||||||||
| Amended Facility Agreement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Proceeds from loan payable with related parties | $ 0 | |||||||||||||||||
| Debt modification description | Pursuant to the Amended Facility Agreement, the Amended Facility Agreement effectively replaced the Hanmi Facility Agreement. The Company evaluated whether the Facility #2 transaction resulted in a debt modification or extinguishment in accordance with ASC 470-50, Debt – Modifications and Extinguishments. The amendment to Facility #1 was accounted for as a debt modification since the amendment did not result in substantially different terms as the present value of the cash flows pursuant to the revised terms is less than 10% different from the remaining cash flows under the terms of the original agreement given that, as of the effective date of the Amended Facility Agreement, no amounts had been advanced to the Company pursuant to Facility #2. | |||||||||||||||||
| Hanmi Pharmaceuticals Co., Ltd. [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Number of common shares held | shares | 7,190 | 508,710 | 508,710 | |||||||||||||||
| Future milestone payments | $ 407,500,000 | |||||||||||||||||
| Proceeds from Issuance of Common Stock | $ 3,000,000 | |||||||||||||||||
| Shares Issued, Price Per Share | $ / shares | $ 51.3 | $ 51.3 | ||||||||||||||||
| Investment Owned, Balance, Shares | shares | 7,190 | 508,710 | 508,710 | |||||||||||||||
| Warrants to purchase common shares, number of warrants | shares | 77,972 | 77,972 | ||||||||||||||||
| Payment of supply costs | $ 0 | $ 2,600,000 | ||||||||||||||||
| Hanmi Pharmaceuticals Co., Ltd. [Member] | Public Offering [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Premium share price (as a percent) | 11.00% | |||||||||||||||||
| Hanmi Pharmaceuticals Co., Ltd. [Member] | Private Placement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Common shares issued (in shares) | shares | 70,175 | |||||||||||||||||
| Shares Issued, Price Per Share | $ / shares | $ 57 | |||||||||||||||||
| Hanmi Pharmaceuticals Co., Ltd. [Member] | Common Shares [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Number of shares sold | shares | 22,281 | |||||||||||||||||
| Hanmi Pharmaceuticals Co., Ltd. [Member] | Common Shares [Member] | Private Placement [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Warrants to purchase common shares, number of warrants | shares | 77,972 | |||||||||||||||||
| Maximum [Member] | Hanmi Pharmaceuticals Co., Ltd. [Member] | ||||||||||||||||||
| Schedule of Equity Method Investments [Line Items] | ||||||||||||||||||
| Investment for ownership interest | $ 7,000,000 | |||||||||||||||||
| Percentage of investment | 19.99% | |||||||||||||||||