Note 3 - Segment Reporting Information - Summarized Financial Information by Reportable Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Net sales	$ 78,843	$ 78,156	$ 258,614	$ 247,973
Operating Income (Loss):
Operating income (loss)	743	(774)	(19,524)	3,110
Capital Expenditures:
Capital expenditures	988	790	2,178	3,534
Depreciation and Amortization:
Depreciation and amortization	2,516	2,084	7,640	5,689
Corporate and Eliminations [Member]
Operating Income (Loss):
Operating income (loss)	(2,654)	(4,414)	(8,997)	(9,573)
Capital Expenditures:
Capital expenditures	17	(8)	108	610
Depreciation and Amortization:
Depreciation and amortization	273	281	848	843
Lighting Segment [Member]
Net sales	61,554	61,693	199,156	192,034
Lighting Segment [Member] | Operating Segments [Member]
Operating Income (Loss):
Operating income (loss)	2,982	4,120	(14,673)	10,972
Capital Expenditures:
Capital expenditures	671	299	1,431	1,600
Depreciation and Amortization:
Depreciation and amortization	1,865	1,446	5,651	3,753
Graphics Segment [Member]
Net sales	17,289	16,463	59,458	55,939
Graphics Segment [Member] | Operating Segments [Member]
Operating Income (Loss):
Operating income (loss)	415	(480)	4,146	1,711
Capital Expenditures:
Capital expenditures	300	499	639	1,324
Depreciation and Amortization:
Depreciation and amortization	$ 378	$ 357	$ 1,141	$ 1,093