Note 2 - Business Segment Information - Summarized Financial Information by Reportable Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Net sales	$ 83,409	$ 78,843	$ 92,305	$ 87,466	$ 83,419	$ 78,156	$ 85,658	$ 84,159	$ 80,844	$ 70,740	$ 84,687	$ 85,925	$ 342,023	$ 331,392	$ 322,196	$ 307,857	$ 299,463
Operating income (loss)													(21,652)	3,609	13,956	$ 7,533	$ 2,318
Capital expenditures													3,406	6,633	10,211
Depreciation and amortization													10,222	8,262	6,677
Corporate and Eliminations [Member]
Operating income (loss)													(14,475)	(12,946)	(10,591)
Capital expenditures													165	636	416
Depreciation and amortization													1,107	1,139	1,214
Lighting Segment [Member]
Net sales													260,613	258,997	244,228
Lighting Segment [Member] | Operating Segments [Member]
Operating income (loss)													(12,795)	14,116	19,301
Capital expenditures													2,203	4,249	6,107
Depreciation and amortization													7,573	5,649	4,359
Graphics Segment [Member]
Net sales													81,410	72,395	77,968
Graphics Segment [Member] | Operating Segments [Member]
Operating income (loss)													5,618	2,439	5,246
Capital expenditures													1,038	1,748	3,688
Depreciation and amortization													$ 1,542	$ 1,474	$ 1,104