Consolidated Statements of Income - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net sales	$ 10,442,600	$ 7,855,900
Operating costs and expenses:
Cost of sales	5,622,200	3,857,100
Advertising	282,600	486,100
Selling	1,615,900	1,249,800
General and administrative	1,080,300	953,100
Total operating costs and expenses	8,601,000	6,546,100
Income from operations	1,841,600	1,309,800
Other income	0	6,200
Interest expense	(41,900)	(7,400)
Income before income taxes	1,799,700	1,308,600
Income tax expense	(718,600)	(552,100)
Net income	$ 1,081,100	$ 756,500
Net income per common share
Basic	$ 0.09	$ 0.06
Diluted	$ 0.09	$ 0.06
Weighted average shares outstanding:
Basic	11,775,897	11,710,745
Diluted	12,082,292	11,927,124