Note 3 - Investment Write-down (Details Textual) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2015
Lumense Inc. [Member]
Cost-method Investments, Other than Temporary Impairment	$ 50,000	$ 700,000
Cost Method Investments	$ 0	$ 50,000	$ 0
Cost-method Investments, Other than Temporary Impairment			$ 750,000

Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=29638308&loc=d3e40346-111594

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant