CONSOLIDATED STATEMENTS OF OPERATIONS (in thousands, except per share data) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 20,328	$ 21,568
Cost of goods sold	9,506	9,018
Gross margin	10,822	12,550
Operating expenses:
Research and development	6,357	6,451
Selling, general and administrative	6,891	7,377
Impairment	652	0
Total operating expenses	13,900	13,828
Operating income (loss)	(3,078)	(1,278)
Non-operating income (expense):
Interest income	14	53
Gain on sale of assets	0	64
Foreign currency transaction gain (loss)	(513)	5
Total non-operating income (loss)	(499)	122
Income (loss) before income taxes	(3,577)	(1,156)
Income tax (expense) benefit	(387)	(31)
Net income (loss)	$ (3,964)	$ (1,187)
Basic earnings (loss) per share	$ (0.48)	$ (0.14)
Diluted earnings (loss) per share	$ (0.48)	$ (0.14)
Weighted-average basic shares	8,333	8,247
Weighted-average diluted shares	8,333	8,247