CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Net sales	$ 9,325	$ 5,285	$ 17,626	$ 15,532
Cost of sales	6,000	2,995	11,112	8,324
Gross profit	3,325	2,290	6,514	7,208
Operating expenses:
Engineering, design and product development	1,804	1,367	3,607	2,752
Selling and marketing	1,767	1,419	3,210	3,627
General and administrative	2,509	2,242	5,118	4,862
Operating expenses	6,080	5,028	11,935	11,241
Operating loss	(2,755)	(2,738)	(5,421)	(4,033)
Interest and other (expense) income:
Interest, net	(29)	(25)	(42)	(22)
Other, net	(17)	(11)	(100)	(176)
Interest and other expense	(46)	(36)	(142)	(198)
Loss before income taxes	(2,801)	(2,774)	(5,563)	(4,231)
Income tax benefit	(687)	(921)	(1,243)	(1,386)
Net loss	$ (2,114)	$ (1,853)	$ (4,320)	$ (2,845)
Net loss per common share:
Basic (in dollars per share)	$ (0.24)	$ (0.25)	$ (0.48)	$ (0.38)
Diluted (in dollars per share)	$ (0.24)	$ (0.25)	$ (0.48)	$ (0.38)
Shares used in per-share calculation:
Basic (in shares)	8,976	7,543	8,962	7,525
Diluted (in shares)	8,976	7,543	8,962	7,525