Note 9 - Stock Option and Stock Plans (Details Textual) - USD ($) | Sep. 26, 2018 | Dec. 31, 2018 | Dec. 31, 2017 |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate | | 276.00% | | |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term | | 5 years | | |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Discount Rate | | 2.96% | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total | | $ 1,775,222 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | 4 years 273 days | | |
Qualified Options [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 6,000,000 | | | |
Stock Option, Exercise Price | $ 0.38 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | 10 years | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 5 years | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance | | 950,000 | [1] | |
Qualified Options [Member] | Stock Owner With Over 10 Percent Ownership [Member] | | | | |
Stock Option, Exercise Price | | $ 0.418 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | 5 years | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | 4 years | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance | | 500,000 | | |
Qualified Options [Member] | If Option Grantee Owns or Controls Over Ten Percent of Outstanding Stock [Member] | | | | |
Stock Option, Exercise Price | $ 0.418 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | 5 years | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 4 years | | | |
Stock Option Price, Percent | 110.00% | | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche One [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche One [Member] | Stock Owner With Over 10 Percent Ownership [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | 25.00% | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Two [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Two [Member] | Stock Owner With Over 10 Percent Ownership [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | 25.00% | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Three [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Three [Member] | Stock Owner With Over 10 Percent Ownership [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | 25.00% | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Four [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Four [Member] | Stock Owner With Over 10 Percent Ownership [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | 25.00% | | |
Qualified Options [Member] | Share-based Compensation Award, Tranche Five [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Nonqualified Options [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 20,000,000 | | | |
Stock Option, Exercise Price | $ 0.38 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | 10 years | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 5 years | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance | | 3,995,000 | | |
Nonqualified Options [Member] | Share-based Compensation Award, Tranche One [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Nonqualified Options [Member] | Share-based Compensation Award, Tranche Two [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Nonqualified Options [Member] | Share-based Compensation Award, Tranche Three [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Nonqualified Options [Member] | Share-based Compensation Award, Tranche Four [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
Nonqualified Options [Member] | Share-based Compensation Award, Tranche Five [Member] | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | |
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[1] | There is one stock owner over 10% currently holding 500,000 qualified options. The exercise price for this option-holder would be $0.418 with an exercise period of 5 years and a vesting period of 4 years at 25% per year. |