Note 7 - Goodwill and Other Intangible Assets (Details Textual)		3 Months Ended			6 Months Ended	9 Months Ended
	Mar. 01, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Number of Reporting Units			1			2
Goodwill, Impairment Loss					$ 20,165,000	$ 20,165,000	$ 28,000,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 0
Intangible Assets, Indefinite-lived, Amount of Fair Value in Excess of Carrying Amount	$ 19,200,000
Intangible Assets, Indefinite-lived, Percentage of Fair Value in Excess of Carrying Amount	462.00%
Amortization of Intangible Assets, Total		691,000		$ 691,000		2,071,000	$ 2,071,000
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year		2,761,000				2,761,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two		2,687,000				2,687,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three		2,682,000				2,682,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four		2,460,000				2,460,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five		2,412,000				2,412,000
Finite-Lived Intangible Assets, Amortization Expense, after Year Five		$ 18,985,000				$ 18,985,000
Lighting Segment [Member]
Number of Reporting Units						1
Goodwill, Impairment Loss					20,165,000	$ 20,165,000
Good will Impairment Testing Value Above Carrying Value	$ 38,900,000
Good will Impairment Testing Percent Value Above Carrying Value	54.00%
Graphics Segment [Member]
Number of Reporting Units						1
Goodwill, Impairment Loss
Good will Impairment Testing Value Above Carrying Value	$ 3,000,000
Good will Impairment Testing Percent Value Above Carrying Value	297.00%