| Note 7 - Major Customer Concentration (Details Textual) - Customer Concentration Risk [Member] | 3 Months Ended | 12 Months Ended | |
|---|---|---|---|
| Dec. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2018 | |
| Sales Revenue, Net [Member] | |||
| Number of Major Customers | 2 | 2 | |
| Accounts Receivable [Member] | |||
| Number of Major Customers | 2 | 3 | |
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- Definition Represents the number of major customers accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc. No definition available. 
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- Details 
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- Details 
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- Details 
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