Note 16 - Significant Customers - Customers Concentration Summary (Details) - Customer Concentration Risk [Member] |
12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Sales Revenue, Net [Member] | Distributor A [Member] | |||||||||
| Concentration risk | 17.00% | 22.00% | 24.00% | ||||||
| Sales Revenue, Net [Member] | Distributor B [Member] | |||||||||
| Concentration risk | [1] | ||||||||
| Sales Revenue, Net [Member] | Distributor C [Member] | |||||||||
| Concentration risk | 10.00% | [1] | [1] | ||||||
| Sales Revenue, Net [Member] | Value-added Reseller D [Member] | |||||||||
| Concentration risk | [1] | ||||||||
| Accounts Receivable [Member] | Distributor A [Member] | |||||||||
| Concentration risk | 16.00% | 19.00% | |||||||
| Accounts Receivable [Member] | Distributor B [Member] | |||||||||
| Concentration risk | [1] | 17.00% | |||||||
| Accounts Receivable [Member] | Distributor C [Member] | |||||||||
| Concentration risk | [1] | ||||||||
| Accounts Receivable [Member] | Value-added Reseller D [Member] | |||||||||
| Concentration risk | 15.00% | [1] | |||||||
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