Note 6 - Major Customers (Details Textual)	12 Months Ended
Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Customer One [Member]
Accounts Receivable, Gross	$ 2,871,000	$ 2,842,000
Customer Two [Member]
Accounts Receivable, Gross	$ 3,088,000	$ 5,512,000
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member]
Number of Major Customers	2	2
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Customer One [Member]
Concentration Risk, Percentage	27.50%	24.60%
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Customer Two [Member]
Concentration Risk, Percentage	16.90%	28.00%

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://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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