Note 7 - Concentrations (Details Textual)	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Number of Areas in Which Operations are Concentrated	1
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| U.S. Government [Member]
Concentration Risk, Percentage	77.00%	65.20%
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Government Customers [Member]
Concentration Risk, Percentage	73.80%	65.20%
Number of Major Customers	4	4
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Commercial Customers [Member]
Concentration Risk, Percentage	19.90%	25.60%
Number of Major Customers	1	1

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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