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Convertible Preferred Stock and Stockholders’ Equity - Part 3 (Details) - USD ($) |  |  |  |  |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |
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Sep. 22, 2025 | Aug. 15, 2025 | Feb. 24, 2025 | Sep. 26, 2024 | Apr. 16, 2024 | Feb. 14, 2024 | May 31, 2023 | May 09, 2023 | Nov. 18, 2022 | Nov. 10, 2022 | Aug. 31, 2025 | Aug. 31, 2024 | Jan. 31, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Jun. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024 | Jun. 24, 2025 | Oct. 31, 2024
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares issued |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,560,820 |  |  | 1,560,820 |  | 138,422 | 241,514 |
Common stock shares outstanding |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,560,668 |  |  | 1,560,668 |  | 138,270 |  |
Repurchase shares of common stock |  |  |  |  |  |  |  |  |  | 125,000 |  |  |  |  |  |  |  |  |  |  |
Price per share (in Dollars per share) |  |  |  |  |  |  |  |  | $ 2 | $ 1 |  |  |  |  |  |  |  |  |  |  |
Repurchases of common stock (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Deferred offering costs (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  | 150,000 |  |  | $ 150,000 |  |  |  |
Warrants outstanding fair value (in Dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 5.48 |  |  |  |
Warrant liability (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  | 12,815,000 |  |  | $ 12,815,000 |  |  |  |
Proceeds from issuance of warrants (in Dollars) | $ 12,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contingent warrant liabilities (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 53,149 |  |  | $ 53,149 |  | $ 43,089 |  |
Settlement share |  |  |  |  |  |  |  |  |  |  |  |  |  | 461 |  |  | 461 |  | 461 |  |
Stock options granted (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of stock options (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 163 |  |  |  |  |
Restricted shares granted |  |  |  |  |  |  | 7 | 44 |  |  |  |  |  |  |  |  |  |  |  |  |
Restricted shares granted vest |  |  |  |  |  |  |  |  |  |  | 25.00% | 25.00% | 50.00% |  |  |  |  |  |  |  |
Shares modified |  |  |  |  |  |  |  | 137 |  |  |  |  |  |  |  |  |  |  |  |  |
Stock options outstanding |  |  |  |  | 144 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average exercise price (in Dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 294.1
Outstanding stock options (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Warrant [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Warrants exercisable |  |  |  |  |  |  |  |  |  |  |  |  |  | 4,376,652 |  |  | 4,376,652 |  |  |  |
Exercise price per share (in Dollars per share) | $ 3.6896 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series C PIPE Warrants [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Warrant liability (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 32,892 |  |  | $ 32,892 |  | 32,982 |  |
Proceeds from issuance of warrants (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 20,257 |  | 10,200 |  |
At the Market Offering Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Deferred offering costs (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 300,000 |  |
Equity Option [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exercise price per share (in Dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of stock options (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 17,000 | $ 53,000 |  | $ 109,000 | $ 220,000 |  |  |
Stock option outstanding shares |  |  |  |  |  |  |  |  |  |  |  |  |  | 120 |  |  | 120 |  | 162 |  |
Weighted average exercise price (in Dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 14,089.83 |  |  | $ 14,089.83 |  | $ 13,258.74 |  |
Chief Executive Officer [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Restricted shares granted |  |  |  |  |  |  |  | 143 |  |  |  |  |  |  |  |  |  |  |  |  |
Chief Financial Officer [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Restricted shares granted |  |  |  |  |  |  |  | 44 |  |  |  |  |  |  |  |  |  |  |  |  |
CBO’s [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Restricted shares granted |  |  |  |  |  |  |  | 22 |  |  |  |  |  |  |  |  |  |  |  |  |
Board of Directors [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Restricted shares granted |  | 2,492 | 20 | 195 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate of stock options |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expense (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 18,000 |  |
Other Current Liabilities [Member] | Series C PIPE Warrants [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contingent warrant liabilities (in Dollars) |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 53,149 |  |  | $ 53,149 |  | $ 43,089 |  |
2022 Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserved for issuance shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 17,058 |  |  | 17,058 |  |  |
Available shares |  |  |  |  |  |  |  |  |  |  |  |  |  | 6,165 |  |  | 6,165 |  |  |  |
PMX Option Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected term |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 11 years |  |  |  |
Stock option outstanding shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 684
Series D Preferred Stock [Member] | Warrant [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Warrants exercisable | 4,362,827 |  |  |  |  |  |  |  |  |  |  |  |  | 4,362,827 |  |  | 4,362,827 |  |  |  |
Common Stock [Member] | Onconetix Equity Incentive Plans [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserved for issuance shares |  |  |  |  |  |  | 926 |  |  |  |  |  |  |  |  |  |  |  |  |  |
IPO [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Preferred Stock and Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement share |  |  |  |  |  |  |  |  |  |  |  |  |  | 6,963 |  |  | 6,963 |  | 6,963 |  |

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