Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales	$ 5,363	$ 5,973
Cost of goods sold	3,140	3,572
Gross profit	2,223	2,401
Operating expenses:
Selling	603	679
General and administrative	876	928
Research and development	657	628
Total operating expenses	2,136	2,235
Operating income	87	166
Other expense -net	(150)	(280)
Change in derivative liability		(142)
Loss before income taxes	(63)	(256)
Provision for income taxes
Net loss	$ (63)	$ (256)
Basic and diluted net loss per share	$ (0.01)	$ (0.03)
Basic and diluted weighted average shares outstanding	8,211	8,122