Statements of Comprehensive Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 7,303,109	$ 11,531,105	$ 15,640,508	$ 19,027,528
Cost of sales	5,786,874	8,455,507	13,131,339	14,490,776
Gross profit	1,516,235	3,075,598	2,509,169	4,536,752
Selling, general and administrative expenses	1,295,687	982,370	2,305,231	1,861,190
Operating income	220,548	2,093,228	203,938	2,675,562
Other income
Interest income	42,376	35,653	94,775	66,877
Other	10,985	7,636	34,657	17,808
Total other income	53,361	43,289	129,432	84,685
Income before provision for income taxes	273,909	2,136,517	333,370	2,760,247
Provision for income taxes	56,151	521,646	53,940	702,612
Net income	217,758	1,614,871	279,430	2,057,635
Other comprehensive income, net of tax:
Unrealized gain (loss) on investment securities	907	(569)	2,254	(850)
Total comprehensive income	$ 218,665	$ 1,614,302	$ 281,684	$ 2,056,785
Net income per share:
Basic	$ 0.09	$ 0.69	$ 0.12	$ 0.88
Diluted	$ 0.09	$ 0.69	$ 0.12	$ 0.88
Weighted average number of shares outstanding:
Basic	2,370,948	2,327,562	2,365,220	2,326,963
Diluted	2,393,933	2,335,293	2,388,002	2,333,764
Dividends per share:	$ 0.25	$ 0.25	$ 1.5	$ 0.50