Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues	$ 7,559	$ 8,155	$ 17,810	$ 16,334
Costs and expenses:
Cost of sales	3,840	2,249	9,150	8,299
Selling, general and administrative	2,801	3,184	8,858	9,825
Research and development	340	285	1,070	880
Costs and Expenses, Total	6,981	5,718	19,078	19,004
Operating income (loss) from operations	578	2,437	(1,268)	(2,670)
Interest expense	(5)	(9)	(14)	(15)
Interest income	1	3	4	16
Other income (expense),net	104	(55)	1,586	83
Income (loss) before income taxes	678	2,376	308	(2,586)
Income tax expense	0	0	(10)	(149)
Net income (loss)	$ 678	$ 2,376	$ 298	$ (2,735)
Net income (loss) per common share:
Basic net income (loss) per common share (in dollars per share)	$ 0.02	$ 0.10	$ 0.01	$ (0.11)
Diluted net income (loss) per common share (in dollars per share)	$ 0.02	$ 0.09	$ 0.01	$ (0.11)
Weighted-average number of common shares outstanding:
Basic (in shares)	30,264,000	24,701,000	29,356,000	24,656,000
Diluted (in shares)	30,335,000	25,120,000	29,482,000	24,656,000