Note 7 - Equity Compensation Plan (Details Textual) - USD ($) | | | | | | | | | | | | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended | | |
Jun. 30, 2023 | Jan. 26, 2023 | Nov. 04, 2022 | Sep. 02, 2022 | Apr. 26, 2022 | Feb. 09, 2022 | Dec. 30, 2021 | Sep. 22, 2021 | Jul. 16, 2020 | May 26, 2020 | Mar. 11, 2020 | Jun. 22, 2021 | Dec. 31, 2020 | Jun. 30, 2023 | Dec. 31, 2022 | Sep. 16, 2020 | May 25, 2020 |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | | | $ 0.96 | $ 1.58 | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | | | | | | 817,500 | 725,000 | | |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 772,000 | | | | | | | | | | | | | $ 772,000 | | | |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) | | | | | | | | | | | | | | 3 years 6 months | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value | $ 0 | | | | | | | | | | | | | $ 0 | | | |
Chief Executive Officer and Chairman [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period (in shares) | | | | | | | | 1,911,160 | | | | | | | | | |
Chief Executive Officer [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | $ 1.66 | | | $ 1.66 | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures (in shares) | | | | | 650,000 | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | 650,000 | | | | | | | | | | | | | | | |
Controller [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | $ 0.85 | $ 0.85 | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures (in shares) | | | 75,000 | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | 75,000 | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Option [Member] | | | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | | | | | | | 383,000 | | | |
Share-Based Payment Arrangement, Option [Member] | Research and Development Expense [Member] | | | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | | | | | | | 104,000 | | | |
Share-Based Payment Arrangement, Option [Member] | General and Administrative Expense [Member] | | | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | | | | | | | 276,000 | | | |
Share-Based Payment Arrangement, Option [Member] | Cost of Sales [Member] | | | | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Expense | | | | | | | | | | | | | | $ 3,000 | | | |
Share-Based Payment Arrangement, Option [Member] | Chief Executive Officer and Chairman [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Accelerated Vesting, Number (in shares) | | | | | | | | 25,000 | | | | | | | | | |
Share-Based Payment Arrangement, Option [Member] | Controller [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | | | 4 years | | | | | | | | | | | | | | |
Share-Based Payment Arrangement, Option [Member] | Vesting Annually [Member] | Chief Executive Officer [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage | | | | | 25% | | | | | | | | | | | | |
The 2019 Plan [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | $ 0.96 | | | | | $ 1.77 | | | | $ 1.50 | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures (in shares) | | 862,500 | | | | | 445,000 | | | | | 388,246 | 500,000 | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) | | | | | | | | | | 1,174,000 | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | | | | | | 4,600,000 | | | | 2,500,000 | | | | | | 4,600,000 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Outstanding Stock Maximum | | | | | | 5% | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 1,368,629 | | | | | | | | | | | | | 1,368,629 | | | |
The 2019 Plan [Member] | Minimum [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | $ 2.90 | | | | | |
The 2019 Plan [Member] | Maximum [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | | | | $ 3.93 | | | | | |
The 2019 Plan [Member] | Chief Executive Officer and Chairman [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | | | | | | | | 10 years | | | | | | | | |
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share) | | | | | | | | | $ 1.50 | | | | | | | | |
The 2019 Plan [Member] | Chief Executive Officer [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures (in shares) | | 142,500 | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | 142,500 | | | | | | | | | | | | | | | |
The 2019 Plan [Member] | Former Employee and Independent Contractor [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period (in shares) | 71,250 | | | | | | | | | | | | | | | | |
The 2019 Plan [Member] | Employee [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | | | | | | | | | | 1,300,000 | | | | | | | 500,000 |
The 2019 Plan [Member] | Vesting Over Two Years [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures (in shares) | | | | | | | | | | | 965,850 | | 375,000 | | | | |
The 2019 Plan [Member] | Vesting Based on Performance Criteria [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures (in shares) | | | | | | | | | | | 321,950 | | 125,000 | | | | |
The 2019 Plan [Member] | Share-Based Payment Arrangement, Tranche One [Member] | Chief Executive Officer and Chairman [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | 600,000 | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | | | | | | | | | 1 year | | | | | | | | |
The 2019 Plan [Member] | Share-Based Payment Arrangement, Tranche Two [Member] | Chief Executive Officer and Chairman [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | | | | | | | | | 200,000 | | | | | | | | |
The 2019 Plan [Member] | Share-Based Payment Arrangement, Option [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | 5 years | | | | | | | | | 10 years | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | | 4 years | | | | | | | | | | | | | | | |
The 2019 Plan [Member] | Share-Based Payment Arrangement, Option [Member] | Minimum [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | | | | | | 5 years | | | | | 5 years | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | | | | | | | 1 year | | | | | 2 years | | | | | |
The 2019 Plan [Member] | Share-Based Payment Arrangement, Option [Member] | Maximum [Member] | | | | | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | | | | | | | 10 years | | | | | 10 years | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | | | | | | | 4 years | | | | | 5 years | | | | | |