Quarterly report pursuant to Section 13 or 15(d)

Note 7 - Registered Direct Offerings (Details Textual)

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Note 7 - Registered Direct Offerings (Details Textual)
 12 Months Ended
Dec. 31, 2022
shares
Feb. 17, 2021
shares
May 12, 2019
item
$ / shares
shares
Jun. 28, 2018
item
$ / shares
shares
Feb. 20, 2017
$ / shares
shares
Sep. 30, 2022
shares
Sep. 30, 2016
USD ($)
Shelf Registration Statement, Maximum Amount Authorized | $             $ 50,000,000
Stock Issued During Period, Shares, New Issues 4,000,000 215,625          
Class Of Series F Warrant [Member]              
Percentage of Warrants Per Unit         0.55    
Class Of Warrant Or Right Acquired Upon Exercise           34,013  
Series F Warrant [Member]              
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares         $ 150.00    
Class of Warrant or Right, Expired During Period (in shares)           27,958  
Class Of Series G Warrant [Member]              
Percentage of Warrants Per Unit       0.75      
Class Of Warrant Or Right Acquired Upon Exercise           43,077  
Class Of Series H Warrant [Member]              
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares     $ 80.00        
The 2017 SPA [Member]              
Stock Issued During Period, Shares, New Issues         50,833    
Shares Issued, Price Per Share | $ / shares         $ 120.00    
The 2018 SPA [Member]              
Stock Issued During Period, Shares, New Issues       45,350      
Shares Issued, Price Per Share | $ / shares       $ 100.00      
Number Of Accredited Investors | item       8      
Registered Direct Offering 2018 [Member] | Class Of Series G Warrant [Member]              
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares       $ 140.00      
The 2019 SPA [Member]              
Stock Issued During Period, Shares, New Issues     43,077        
Shares Issued, Price Per Share | $ / shares     $ 65.00        
Number Of Accredited Investors | item     5