Note 13 - Restructuring Costs (Details Textual)		3 Months Ended			9 Months Ended
	Oct. 29, 2018 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($) ft²	Mar. 31, 2018 USD ($)	Mar. 31, 2019 USD ($) ft²	Mar. 31, 2018 USD ($)
Restructuring and Related Cost, Incurred Cost (Gain)			$ 368,000		$ 924,000
Inventory Write-down					2,574,000	$ 1,762,000
Fixed Asset Impairment and Accelerated Depreciation Expense					228,000
Forecast [Member]
Proceeds from Sale of Manufacturing Facility, Gross		$ 12,000,000
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	200,000
Expected Write-down of Inventory	$ 600,000
Restructuring and Related Cost, Incurred Cost (Gain)					769,000
Inventory Write-down					919,000
Sell Manufacturing Facility In New Windsor, New York [Member] | Forecast [Member]
Proceeds from Sale of Manufacturing Facility, Gross		$ 12,000,000
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		12,000
Closure of Leased Facility in Hawthorne, California [Member] | Cost of Sales [Member]
Inventory Write-down					$ 1,067,000