Note 13 - Restructuring Costs (Details Textual)		3 Months Ended		6 Months Ended
	Oct. 29, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 ft²
Restructuring and Related Cost, Incurred Cost (Gain)		$ 401,000		$ 556,000
Inventory Write-down				2,043,000	$ 1,033,000
Fixed Asset Impairment and Accelerated Depreciation Expense				228,000
Closure of Lighting Facility in New Windsor, New York [Member]
Expected Annual Savings from Closure of Facility	$ 4,000,000
Restructuring and Related Cost, Expected Cost, Total	800,000
Expected Write-down of Inventory	$ 1,500,000
Restructuring and Related Cost, Incurred Cost (Gain)				401,000
Inventory Write-down				919,000
Closure of Leased Facility in Hawthorne, California [Member]
Restructuring and Related Cost, Incurred Cost (Gain)				155,000
Inventory Write-down				148,000
Area of Real Estate Property | ft²						12,000
Closure of Leased Facility in Hawthorne, California [Member] | Cost of Sales [Member]
Inventory Write-down		$ 632,000		$ 1,067,000