CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 32,311	$ 31,176
Cost of sales	21,880	21,552
Gross margin	10,431	9,624
Selling, general and administrative expense	5,411	5,334
Operating income	5,020	4,290
Interest income	607	837
Income before taxes	5,627	5,127
Provision for income taxes	1,356	1,141
Net income	$ 4,271	$ 3,986
Basic and diluted net income per common share	$ 0.34	$ 0.32
Basic and diluted weighted average shares outstanding	12,443	12,436