CONSOLIDATED STATEMENTS OF OPERATIONS (in thousands, except per share data) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 21,568	$ 29,224
Cost of goods sold	9,018	11,868
Gross margin	12,550	17,356
Operating expenses:
Research and development	6,451	7,361
Selling, general and administrative	7,377	8,257
Total operating expenses	13,828	15,618
Operating income (loss)	(1,278)	1,738
Non-operating income (expense):
Interest income	53	37
Gain on sale of assets	64	19
Foreign currency transaction gain (loss)	5	103
Total non-operating income	122	159
Income (loss) before income taxes	(1,156)	1,897
Income tax (expense) benefit	(31)	(291)
Net income (loss)	$ (1,187)	$ 1,606
Basic earnings (loss) per share	$ (0.14)	$ 0.19
Diluted earnings (loss) per share	$ (0.14)	$ 0.19
Weighted-average basic shares	8,247	8,378
Weighted-average diluted shares	8,247	8,514