CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) [Abstract]
Net sales	$ 61,439,929	$ 60,860,852	$ 122,323,077	$ 120,305,849
Cost of products sold	(46,430,039)	(45,807,496)	(93,504,144)	(90,531,018)
Gross margin	15,009,890	15,053,356	28,818,933	29,744,831
Product development expenses	(2,174,803)	(1,581,719)	(4,414,579)	(3,084,258)
Selling and administrative expenses	(8,076,501)	(9,083,131)	(16,474,766)	(18,130,180)
Restructuring costs	(1,799,293)	0	(2,635,987)	0
Operating profit	2,959,293	4,388,506	5,293,601	8,560,393
Interest expense	(261,618)	(312,060)	(554,158)	(608,390)
Other income	586,823	225,769	600,748	444,500
Income before income taxes	3,284,498	4,302,215	5,340,191	8,396,503
Income taxes	754,725	1,043,738	1,239,458	2,037,831
Net income	$ 2,529,773	$ 3,258,477	$ 4,100,733	$ 6,358,672
Earnings per Share:
Basic (in dollars per share)	$ 0.41	$ 0.52	$ 0.66	$ 1.02
Diluted (in dollars per share)	0.40	0.52	0.65	1.01
Cash dividends per share: (in dollars per share)	$ 0.11	$ 0.11	$ 0.22	$ 0.22