Statements of Comprehensive Income - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net sales	$ 7,242,020	$ 5,697,083	$ 13,521,456	$ 11,390,555
Cost of sales	5,653,977	3,438,348	9,965,093	7,321,741
Gross profit	1,588,043	2,258,735	3,556,363	4,068,814
Selling, general and administrative expenses	754,958	633,177	1,504,608	1,231,379
Operating income	833,085	1,625,558	2,051,755	2,837,435
Other income
Interest income	10,610	9,061	18,063	17,054
Other	26,563	10,937	44,551	20,594
Total other income	37,173	19,998	62,614	37,648
Income before income taxes	870,258	1,645,556	2,114,369	2,875,083
Provision for income taxes	255,831	426,474	621,412	744,780
Net income	614,427	1,219,082	1,492,957	2,130,303
Other comprehensive income, net of tax:
Unrealized (loss) gain on investment securities	(905)	(1,093)	874	(1,413)
Total comprehensive income	$ 613,522	$ 1,217,989	$ 1,493,831	$ 2,128,890
Net income per share:
Basic	$ 0.27	$ 0.54	$ 0.65	$ 0.94
Diluted	$ 0.27	$ 0.54	$ 0.65	$ 0.93
Weighted average number of shares outstanding:
Basic	2,276,401	2,265,460	2,280,262	2,268,205
Diluted	2,294,020	2,274,004	2,298,913	2,281,049
Dividends per share:	$ 0.25	$ 0.25	$ 0.50	$ 0.50