Quarterly report [Sections 13 or 15(d)]

Note 4 - Fair Value Measurements (Details Textual)

v3.26.1
Note 4 - Fair Value Measurements (Details Textual)
3 Months Ended 6 Months Ended
Apr. 01, 2026
USD ($)
shares
Mar. 25, 2026
Sep. 22, 2025
USD ($)
shares
Aug. 08, 2025
Aug. 05, 2025
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2025
USD ($)
shares
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2025
USD ($)
shares
Sep. 30, 2025
shares
Proceeds from Sale of Equity Securities, FV-NI | $               $ 3,168,910 $ 393,217  
Equity Securities, FV-NI, Unrealized Gain (Loss) | $           $ 1,976,872 $ 0 $ 1,730,192 $ 0  
Reverse Stock Split [Member]                    
Stockholders' Equity Note, Stock Split, Conversion Ratio       10 10          
Reverse Stock Split [Member] | ONCO [Member]                    
Stockholders' Equity Note, Stock Split, Conversion Ratio   5                
Series D Preferred Stock [Member] | ONCO [Member]                    
Investment Owned, Balance, Shares (in shares)     16,099     1,196   1,196   3,125
ONCO Warrant [Member]                    
Investment Owned, Balance, Shares (in shares)     169,395              
ONCO Warrant [Member] | ONCO [Member]                    
Investment Owned, Balance, Shares (in shares)     872,565     169,395   169,395   169,395
ONCO Series D Preferred Stock and ONCO Warrant [Member] | ONCO [Member]                    
Proceeds from Sale of Equity Securities, FV-NI | $     $ 12,900,000              
ONCO Series D Preferred Stock [Member]                    
Investment Owned, Balance, Shares (in shares)     3,125              
ONCO Series D Preferred Stock [Member] | Conversion of Series D Preferred Stock into Common Stock [Member]                    
Conversion of Stock, Shares Converted (in shares)           1,929        
ONCO Series D Preferred Stock [Member] | Conversion of Series D Preferred Stock into Common Stock [Member] | Subsequent Event [Member]                    
Conversion of Stock, Shares Converted (in shares) 1,196                  
ONCO Series D Preferred Stock [Member] | ONCO [Member] | Calibration Discount Rate [Member]                    
Unobservable input           0   0    
ONCO Common Stock [Member] | Conversion of Series D Preferred Stock into Common Stock [Member]                    
Conversion of Stock, Shares Issued (in shares)           771,091        
ONCO Common Stock [Member] | Conversion of Series D Preferred Stock into Common Stock [Member] | Subsequent Event [Member]                    
Conversion of Stock, Shares Issued (in shares) 1,041,743                  
Common Stock [Member]                    
Equity Securities, FV-NI, Unrealized Gain (Loss) | $             $ (300,000)      
Common Stock [Member] | ONCO [Member]                    
Investment Owned, Balance, Shares (in shares)           770,772 28,549 770,772 28,549  
Proceeds from Sale of Equity Securities, FV-NI | $           $ 3,200,000 $ 400,000      
Common Stock [Member] | ONCO [Member] | Subsequent Event [Member]                    
Investment Owned, Balance, Shares (in shares) 1,042,062                  
Proceeds from Sale of Equity Securities, FV-NI | $ $ 1,800,000