Note 3 - Segment Reporting Information - Inter-segment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Net sales	$ 78,156	$ 70,740	$ 247,973	$ 241,352
Lighting Segment [Member]
Net sales	56,039	49,331	176,578	168,007
Graphics Segment [Member]
Net sales	16,463	17,236	55,939	60,772
Technology Segment [Member]
Net sales	5,654	4,173	15,456	12,573
Intersegment Eliminations [Member] | Lighting Segment [Member]
Net sales	442	715	1,929	2,143
Intersegment Eliminations [Member] | Graphics Segment [Member]
Net sales	216	275	1,028	1,281
Intersegment Eliminations [Member] | Technology Segment [Member]
Net sales	$ 8,715	$ 8,920	$ 25,846	$ 27,236