v3.26.1
Note 3 - Stockholders' Equity (Details Textual) - USD ($)
 1 Months Ended 3 Months Ended 6 Months Ended
Jan. 15, 2026
Nov. 26, 2025
Nov. 19, 2025
Aug. 27, 2025
May 19, 2025
Mar. 18, 2025
Jun. 09, 2021
Aug. 06, 2026
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Jan. 14, 2026
Dec. 31, 2025
Nov. 17, 2025
Nov. 04, 2025
Jun. 04, 2025
May 02, 2025
Mar. 26, 2025
Jan. 21, 2025
Dec. 31, 2024
Nov. 12, 2024
Oct. 01, 2024
Sep. 30, 2024
Aug. 13, 2024
Jul. 01, 2024
Apr. 01, 2024
Nov. 06, 2023
Jun. 07, 2023
Dec. 14, 2022
Sep. 30, 2022
May 05, 2022
Mar. 21, 2022
Nov. 15, 2021
May 28, 2021
Jan. 15, 2021
Sep. 15, 2020
May 29, 2019
Common Stock, Par or Stated Value Per Share (in dollars per share)                   $ 0.01   $ 0.01     $ 0.01                             $ 0.01                  
Common Stock, Shares Authorized (in shares)                   1,600,000,000   1,600,000,000     1,600,000,000     1,600,000,000                       1,200,000,000                  
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)                       200,000                                                      
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)                       $ 0.21                                                      
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount                   $ 0 $ 0 $ 0 $ 0                                                    
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)         $ 25                                                                    
Class Of Warrant Or Right, Issued In Period (in shares)       9,019,652 15,000,000                                                                    
Warrants and Rights Outstanding, Term (Year)                                             1 year               1 year     1 year       2 years 1 year
ZNWAS Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) [1],[2]                   $ 0.25   $ 0.25                                                      
ZNWAT Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                   0.18   0.18                                                      
ZNWAU Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                   0.25   0.25                                                      
ZNWBA Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                   0.25   0.25                                                      
Waiver Term Sheet Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                                 $ 0.05                                            
Equity Agreement, Amount Authorized       $ 2,500,000                         $ 250,000                                            
ZNWBB Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                   $ 0.25   $ 0.25                                                      
Class Of Warrant Or Right, Issued In Period (in shares)         15,000,000                                                                    
ZNWBC Warrants [Member]                                                                              
Proceeds from Warrant Exercises   $ 76,000                                                                          
Class Of Warrant Or Right, Issued In Period (in shares)     1,519,136                                                                        
Share-Based Payment Arrangement, Nonemployee [Member]                                                                              
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)                       0 0                                                    
The 2021 Omnibus Incentive Stock Options Plan [Member]                                                                              
Common Stock, Capital Shares Reserved for Future Issuance (in shares)             38,000,000                                                                
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)             10 years                                                                
The 2021 Omnibus Incentive Stock Options Plan [Member] | Five Senior Officers and Two Staff Members [Member]                                                                              
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)                       175,000 175,000                                                    
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)                       $ 0.24 $ 0.1                                                    
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Grant Date Fair Value                       $ 36,000 $ 15,000                                                    
The 2021 Omnibus Incentive Stock Options Plan [Member] | One Senior Officer [Member]                                                                              
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)                       25,000 25,000                                                    
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)                       $ 0.01 $ 0.01                                                    
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Grant Date Fair Value                       $ 6,000 $ 3,000                                                    
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member]                                                                              
Subscriptions Receivable from Shareholders or Affiliates for Issuance of Capital Stock               $ 237,000       208,000 179,000                                                    
Proceeds from Issuance or Sale of Equity               $ 1,115,000   $ 3,385,000 $ 7,740,000 $ 11,394,000 $ 13,780,000                                                    
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | Investor Concentration Risk [Member] | Proceeds From Issuance [Member]                                                                              
Concentration Risk, Percentage                       24.00% 66.00%                                                    
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWAM Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)           $ 5                                                             $ 1    
Warrants Exercised (in shares)           4,376,000                                                                  
Proceeds from Warrant Exercises           $ 219,000                                                                  
Class of Warrant or Right, Outstanding (in shares)                                       0                                      
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWAP Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                                                                       $ 0.25      
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                                                                       1      
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWAQ Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)           $ 5                                                     $ 0.05            
Proceeds from Warrant Exercises                 $ 1,171,000                                                            
Class of Warrant or Right, Exercised in Period (in shares)                 23,428,348                                                            
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWAS Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                                                                     $ 1        
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWAT Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 0.25     $ 18                                                       $ 0.25              
Class Of Warrant Or Right, Issued In Period (in shares) 145,180,117     9,019,652                                                                      
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWAU Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 0.25                                                                            
Class Of Warrant Or Right, Issued In Period (in shares) 19,147,462                                                                            
Dividend Reinvestment and Stock Purchase Plan (DSPP) [Member] | ZNWBA Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                 $ 0.25                                       $ 0.25                    
Class of Warrant or Right, Outstanding (in shares)                   0   0                                                      
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                                                         1                    
Waiver Term Sheet Agreement [Member]                                                                              
Equity Agreement, Amount Authorized                           $ 5,000,000   $ 1,500,000     $ 15,000,000   $ 15,000,000 $ 10,000,000   $ 10,000,000     $ 5,000,000 $ 10,000,000                      
Equity Agreement, Share Price Threshold (in dollars per share)                                         $ 0.2   $ 0.2         $ 0.15                      
Waiver Term Sheet Agreement [Member] | Waiver Term Sheet Warrants [Member]                                                                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                                         $ 0.25       $ 0.25 $ 0.25   $ 0.25                      
Class of Warrant or Right, Outstanding (in shares)                                     15,000,000                                        
Warrants and Rights Outstanding                                         $ 15,000,000       $ 10,000,000 $ 10,000,000   $ 5,000,000                      
[1] On November 12, 2024, the Company extended the expiration date of the ZNWAA warrant by one (1) year. The newexpiration date is January 31, 2026.
[2] These warrants were issued and become exercisable beginning on January 15, 2026 and expire on June 30, 2026.