Note 10 - Significant Customers (Details Textual) - Customer Concentration Risk [Member]	9 Months Ended	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Sales Revenue, Net [Member]
Number of Major Customers	1
Concentration Risk, Percentage	31.00%	33.00%
Accounts Receivable [Member]
Number of Major Customers	1
Concentration Risk, Percentage	42.00%		23.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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