Note 5 - Share-based Compensation (Details Textual) - USD ($) | | | | | | | | 3 Months Ended | 9 Months Ended |
Sep. 30, 2024 | Aug. 13, 2024 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Jun. 22, 2018 | Sep. 07, 2017 | Sep. 30, 2024 | Jun. 30, 2024 | Mar. 31, 2024 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Sep. 30, 2024 | Sep. 30, 2023 |
Stock Issued During Period, Value, Issued for Services | | | | | | | | $ 63,000 | $ 116,000 | $ 83,000 | $ 37,000 | $ 75,000 | $ 207,000 | | |
Share Price (in dollars per share) | $ 0.23 | | | | | | | $ 0.23 | | | | | | $ 0.23 | |
Proceeds from Stock Options Exercised | | | | | | | | | | | | | | $ 153,000 | $ 0 |
2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | | | | | | | | | | | | | 10 years | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Per Year (in shares) | | | | | | | | | | | | | | 2 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | 50,000,000 | | | | | | | 50,000,000 | | | | | | 50,000,000 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 46,517,730 | | | | | | | 46,517,730 | | | | | | 46,517,730 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 3,482,270 | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | | | $ 0.25 | |
2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | | | | | 10 years | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Per Year (in shares) | | | | | | 2,000,000 | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 9,343,614 | | | | | | | 9,343,614 | | | | | | 9,343,614 | |
Share Price (in dollars per share) | $ 0.23 | | | | | | | $ 0.23 | | | | | | $ 0.23 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 1,547,938 | 8,219,920 |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 626,000 | | | | | | | $ 626,000 | | | | | | $ 626,000 | |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) | | | | | | | | | | | | | | 4 years | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | | | $ 0.3 | $ 0.18 |
Equity Incentive Plan 2007 [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | | | | | | 10 years | | | | | | | | |
Share Price (in dollars per share) | $ 0.23 | | | | | | | $ 0.23 | | | | | | 0.23 | |
Non Plan [Member] | | | | | | | | | | | | | | | |
Share Price (in dollars per share) | $ 0.23 | | | | | | | $ 0.23 | | | | | | $ 0.23 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 85,251 | 60,040 |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | | | $ 0.23 | $ 0.2 |
Share-Based Payment Arrangement, Option [Member] | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | $ 43,000 | | | 45,000 | | | $ 165,000 | $ 172,000 |
Share-Based Payment Arrangement, Option [Member] | 2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 276,000 | | | | | | | 276,000 | | | | | | $ 276,000 | |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) | | | | | | | | | | | | | | 4 years | |
Selling, General and Administrative Expenses [Member] | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | $ 237,000 | | | $ 725,000 | | | $ 1,264,000 | $ 1,269,000 |
Officer [Member] | | | | | | | | | | | | | | | |
Stock Issued During Period, Value, Issued for Services | $ 9,000 | | $ 12,000 | $ 12,000 | $ 6,000 | | | | | | | | | | |
Stock Issued During Period, Shares, Issued for Services (in shares) | 41,087 | | 69,563 | 68,541 | 30,747 | | | | 0 | 0 | | | | | |
Shares Issued, Price Per Share (in dollars per share) | $ 0.23 | | $ 0.17 | $ 0.18 | $ 0.2 | | | $ 0.23 | | | $ 0.17 | $ 0.18 | $ 0.2 | $ 0.23 | $ 0.17 |
Consultants [Member] | | | | | | | | | | | | | | | |
Stock Issued During Period, Value, Issued for Services | | | | | | | | $ 54,000 | $ 116,000 | $ 83,000 | $ 25,000 | $ 63,000 | $ 201,000 | | |
Stock Issued During Period, Shares, Issued for Services (in shares) | | | | | | | | 219,816 | 446,989 | 288,997 | 146,123 | 352,370 | 899,743 | | |
Shares Issued, Price Per Share (in dollars per share) | $ 0.23 | | $ 0.17 | $ 0.18 | $ 0.2 | | | $ 0.23 | $ 0.26 | $ 0.35 | $ 0.17 | $ 0.18 | $ 0.2 | $ 0.23 | $ 0.17 |
Consultants [Member] | 2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 697,616 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 223,000 | |
Board of Directors, Employees, and Consultants [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 1,547,938 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 418,000 | |
Board of Directors, Employees, and Consultants [Member] | 2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 3,482,270 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 782,000 | |
Board of Directors, Employees, and Consultants [Member] | 2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 544,841 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 173,000 | |
Board Of Directors [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 267,746 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 85,000 | |
Board Of Directors [Member] | 2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 771,180 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 171,000 | |
Board Of Directors [Member] | 2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | | 1,565,858 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | | $ 266,000 |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | $ 0.17 | $ 0.18 | $ 0.2 | | |
Employees [Member] | Employee Retention Program [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | | 1,784,140 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | | $ 306,000 |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | | | | | | | | | | | | | | | 4 years |
Employees [Member] | Employee Retention Program [Member] | 2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 1,013,474 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 154,000 | |
Employees [Member] | Employee Retention Program [Member] | 2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 735,351 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 160,000 | |
Chief Financial Officer [Member] | 2024 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 1,000,000 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | $ 234,000 | |
Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | | 800,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | | $ 141,000 |
Chief Financial Officer [Member] | Share-Based Payment Arrangement, Option [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | 10 years | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | 300,000 | | | | | | | | | | | | | |
Engagement Extension, Term (Year) | | 1 year | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross, Per Month (in shares) | | 25,000 | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share) | | $ 0.24 | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Available Grants in Period, Gross, Upon Renewal (in shares) | | 300,000 | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vesting Period for Renewable Options (Year) | | 1 year | | | | | | | | | | | | | |
Chief Financial Officer [Member] | Share-Based Payment Arrangement, Option [Member] | 2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | | 500,000 |
Officer, Board of Directors, Employees, and a Consultant [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | | 8,219,920 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value | | | | | | | | | | | | | | | $ 1,370,000 |
Employees and Consultants [Member] | 2018 Equity Incentive Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | | 4,069,922 |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | | | | $ 657,000 |
Vendors [Member] | Non Plan [Member] | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | | | | | | | $ 18,000 | $ 11,000 |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 85,251 | 60,040 |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | | | | $ 0.2 |
Remaining Stock Option Plan Expense | $ 109,000 | | | | | | | $ 109,000 | | | | | | $ 109,000 | |
Investors [Member] | Share-Based Payment Arrangement, Option [Member] | Non Plan [Member] | | | | | | | | | | | | | | | |
Proceeds from Stock Options Exercised | | | | | | | | | | | | | | $ 153,000 | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | | | | | | | | | 463,882 | |