Note 3 - Segment Reporting Information - Summarized Financial Information by Reportable Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net Sales:
Net sales	$ 87,466	$ 84,159
Operating Income (Loss):
Operating income (loss)	(24,814)	1,066
Capital Expenditures:
Capital expenditures	498	1,960	$ 498	$ 1,960
Depreciation and Amortization:
Depreciation and amortization	2,572	1,835	$ 2,572	$ 1,835
Corporate and Eliminations [Member]
Operating Income (Loss):
Operating income (loss)	(3,360)	(3,042)
Capital Expenditures:
Capital expenditures	55	498
Depreciation and Amortization:
Depreciation and amortization	292	283
Lighting Segment [Member]
Net Sales:
Net sales	68,428	65,265
Lighting Segment [Member] | Operating Segments [Member]
Operating Income (Loss):
Operating income (loss)	(22,930)	3,091
Capital Expenditures:
Capital expenditures	261	1,096
Depreciation and Amortization:
Depreciation and amortization	1,901	1,192
Graphics Segment [Member]
Net Sales:
Net sales	19,038	18,894
Graphics Segment [Member] | Operating Segments [Member]
Operating Income (Loss):
Operating income (loss)	1,476	1,017
Capital Expenditures:
Capital expenditures	182	366
Depreciation and Amortization:
Depreciation and amortization	$ 379	$ 360