CONSOLIDATED STATEMENTS OF OPERATIONS (in thousands, except per share amounts) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net Sales	$ 7,204	$ 9,135	$ 14,834	$ 16,359
Cost of goods sold	2,955	3,933	6,169	6,990
Gross margin	4,249	5,202	8,665	9,369
Operating expenses:
Research and development	1,845	1,771	3,724	3,316
Selling, general and administrative	2,158	2,163	4,351	3,981
Total operating expenses	4,003	3,934	8,075	7,297
Operating income	246	1,268	590	2,072
Non-operating income (expense):
Interest income	9	6	16	13
Gain on sale of assets	4	80	4	291
Foreign currency transaction gain (loss)	269	(62)	93	(92)
Total non-operating income	282	24	113	212
Income before income taxes	528	1,292	703	2,284
Income tax (expense)	(42)	(86)	(87)	(99)
Net income	$ 486	$ 1,206	$ 616	$ 2,185
Basic earnings per share	$ 0.06	$ 0.15	$ 0.07	$ 0.27
Diluted earnings per share	$ 0.06	$ 0.14	$ 0.07	$ 0.26
Weighted-average basic shares	8,356	8,104	8,321	8,067
Weighted-average diluted shares	8,500	8,408	8,521	8,367