v3.26.1
Cover - shares
6 Months Ended
Jun. 30, 2026
Aug. 12, 2026
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2026  
Current Fiscal Year End Date --12-31  
Entity File Number 001-37649  
Entity Registrant Name FIEE, INC.  
Entity Central Index Key 0001467761  
Entity Tax Identification Number 04-2621506  
Entity Incorporation, State or Country Code DE  
Entity Address, Address Line One 3-33, 2-chome Utajima  
Entity Address, Address Line Two Nishiyodogawa District  
Entity Address, City or Town Osaka  
Entity Address, Country JP  
Entity Address, Postal Zip Code 555-0021  
City Area Code +81 6  
Local Phone Number 7509 3700  
Title of 12(b) Security Common Stock, $0.01 par value per share  
Trading Symbol FIEE  
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   8,528,598