| Note 9 - Lease Liability (Details Textual) | Dec. 31, 2019 | 
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| Lessee, Operating Lease, Renewal Term | 5 years | 
| X | ||||||||||
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- Definition Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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