Note 10 - Related Party Transactions (Details Textual) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
|
| Director [Member] | ||||
| Common Stock, Percentage of Beneficial Stock Outstanding | 5.00% | 5.00% | ||
| BHS [Member] | Royalty Agreement and License [Member] | ||||
| Royalty Expense | $ 11,000 | $ 35,000 | $ 19,000 | $ 50,000 |
| Related Party Transaction, Automatic Renewal Period of Agreement (Year) | 1 year | |||
| Number of Days Termination Notice (Day) | 90 days | |||
| X | ||||||||||
- Definition Represents the percentage of beneficial stock outstanding. No definition available.
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| X | ||||||||||
- Definition Represents the number of days for termination notice. No definition available.
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| X | ||||||||||
- Definition Represents the automatic renewal period of the agreement in related party transaction. No definition available.
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| X | ||||||||||
- Definition Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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