v3.26.1
COVER PAGE - shares
3 Months Ended
Mar. 31, 2026
May 07, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Current Fiscal Year End Date --12-31  
Document Transition Report false  
Entity File Number 001-36812  
Entity Registrant Name Decoy Therapeutics Inc.  
Entity Incorporation, State or 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, $0.0001 par value  
Trading Symbol DCOY  
Security Exchange Name NASDAQ  
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  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   531,968
Entity Central Index Key 0001615219  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Amendment Flag false