Note 2 - Summary of Significant Accounting Policies - Fair Value of Goodwill (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Total Gains (Losses)	$ (28,000,000)		$ (28,000,000)
Lighting Segment [Member]
Total Gains (Losses)	(28,000,000)
Fair Value, Measurements, Nonrecurring [Member] | Lighting Segment [Member]
Goodwill	29,373,000		29,373,000
Total Gains (Losses)			(28,000,000)
Fair Value, Measurements, Nonrecurring [Member] | Lighting Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Goodwill
Fair Value, Measurements, Nonrecurring [Member] | Lighting Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Goodwill
Fair Value, Measurements, Nonrecurring [Member] | Lighting Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Goodwill	$ 29,373,000		$ 29,373,000