Note 10 - Significant Business Concentrations and Risk (Details Textual)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Major Suppliers	1
Sales Revenue, Net [Member] \| Customer Concentration Risk [Member]
Number Of Major Customers	5	5	5
Concentration Risk, Percentage	1.20%	1.40%	1.30%
Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Number Of Major Customers	2	2
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| Two Major Customers [Member]
Concentration Risk, Percentage	21.40%	35.20%

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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611

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Balance Type:	na
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