Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2025	Jun. 30, 2025
Cover [Abstract]
Entity Registrant Name	Decoy Therapeutics Inc.
Entity Central Index Key	0001615219
Document Type	10-K/A
Document Annual Report	true
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Document Period End Date	Dec. 31, 2025
Document Fiscal Year Focus	2025
Amendment Flag	true
Amendment Description	Decoy Therapeutics Inc. (the “Company,” “we,” “us” or “our”) is filing this Amendment No. 1 on Form 10-K/A (this “Amendment”) to its Annual Report on Form 10-K for the fiscal year ended December 31, 2025, originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 31, 2026 (the “Original 10-K”), solely for the purpose of including the information required by Items 10 through 14 of Part III of Form 10-K. This information was previously omitted from the Original 10-K in reliance on General Instruction G(3) to Form 10-K, which permits the information in the above-referenced items to be incorporated in the Original 10-K by reference from the Company’s definitive proxy statement so long as such proxy statement is filed no later than 120 days after the Company’s fiscal year-end. The Company is filing this Amendment to include the Part III information in the Original 10-K because it will not file a definitive proxy statement containing such information within 120 days after the end of the fiscal year covered by the Original 10-K.This Amendment amends and restates in their entirety Items 10 through 14 of the Original 10-K. Except as described above, this Amendment does not amend, update or change any other items or disclosures in the Original 10-K and does not reflect events occurring after the filing of the Original 10-K. Accordingly, this Amendment should be read in conjunction with the Original 10-K and the Company’s other filings made with the SEC subsequent to the filing of the Original 10-K. Defined terms used, but not defined, herein have the meanings ascribed to them in the Original 10-K. Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), this Amendment also contains new certifications by the Company’s principal executive officer and principal financial officer as required by Section 302 of the Sarbanes-Oxley Act of 2002. Item 15(a)(3) of Part IV of the Original 10-K is amended to include the currently dated certifications as exhibits. No financial statements are included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K; accordingly, paragraphs 3, 4 and 5 of the certifications have been omitted. Similarly, because no financial statements have been included in this Amendment, certifications pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 have been omitted.On November 12, 2025, the Company (then known as Salarius Pharmaceuticals, Inc.) completed its previously announced merger transaction (the “Merger”) with Decoy Therapeutics, Inc. (“Legacy Decoy”) pursuant to the Agreement and Plan of Merger, dated as of January 10, 2025, as amended. On January 8, 2026, the Company changed its legal name from “Salarius Pharmaceuticals, Inc.” to “Decoy Therapeutics Inc.” Except where the context otherwise requires or where otherwise indicated, all historical references to “Salarius” in this Amendment refer to the Company prior to the name change. All share and per share amounts set forth in this Amendment have been adjusted to reflect the 1-for-15 reverse stock split effected on August 15, 2025 and the 1-for-12 reverse stock split effected on March 6, 2026.
Entity File Number	001-36812
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	46-5087339
Entity Address, Address Line One	2450 Holcombe Blvd.
Entity Address, Address Line Two	Suite X
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77021
City Area Code	713
Local Phone Number	913-5608
Title of 12(b) Security	Common Stock, par value $ 0.0001
Trading Symbol	DCOY
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float		$ 1,896,114
Documents Incorporated by Reference [Text Block]	None.

Decoy Therapeutics Inc. 10-K/A