Note 7 - Leases - Weighted Average Remaining Lease Term and Discount Rate (Details)  | 
Dec. 31, 2020  | 
Dec. 31, 2019  | 
|---|---|---|
| Weighted average remaining lease term: (Year) | 14 years 9 months 18 days | 14 years 3 months 18 days | 
| Weighted average discount rate: | 10.20% | 10.40% | 
| X | ||||||||||
- Definition Weighted average discount rate for operating lease calculated at point in time. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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