CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statements of Comprehensive Income (Loss) [Abstract]
Net sales	$ 2,244	$ 2,045
Cost of goods sold	1,164	1,023
Gross profit	1,080	1,022
Operating expenses
Selling and marketing	351	370
General and administrative	567	522
Research and development	262	268
Total operating expenses	1,180	1,160
Operating loss	(100)	(138)
Non-operating income
Interest income	116	93
Total non-operating income, net	116	93
Income (loss) before income tax expense (benefit)	16	(45)
Income tax expense (benefit)	5	(1)
Net income (loss)	11	(44)
Other comprehensive loss
Change in unrealized value of available-for-sale securities, net of income tax	0	(4)
Other comprehensive loss	0	(4)
Net comprehensive income (loss)	$ 11	$ (48)
Basic
Net income (loss) per share	$ 0	$ (0.01)
Weighted average shares	3,428,021	3,428,021
Diluted
Net income (loss) per share	$ 0	$ (0.01)
Weighted average shares	3,428,021	3,428,021