Statements of Comprehensive Income (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 9,218,141	$ 5,663,161	$ 24,858,649	$ 24,690,689
Cost of sales	7,067,702	4,407,957	20,199,041	18,898,733
Gross profit	2,150,439	1,255,204	4,659,608	5,791,956
Selling, general and administrative expenses	1,069,070	895,129	3,374,301	2,756,319
Operating income	1,081,369	360,075	1,285,307	3,035,637
Other income
Interest income	38,623	42,684	133,398	109,561
Other	6,631	13,428	41,288	31,236
Total other income	45,254	56,112	174,686	140,797
Income before provision for income taxes	1,126,623	416,187	1,459,993	3,176,434
Provision for income taxes	204,167	98,423	258,107	801,035
Net income	922,456	317,764	1,201,886	2,375,399
Other comprehensive income, net of tax:
Unrealized gain (loss) on investment securities	1,512	(2,143)	3,766	(2,993)
Total comprehensive income	$ 923,968	$ 315,621	$ 1,205,652	$ 2,372,406
Net income per share:
Basic	$ 0.39	$ 0.14	$ 0.51	$ 1.02
Diluted	$ 0.39	$ 0.14	$ 0.50	$ 1.02
Weighted average number of shares outstanding:
Basic	2,378,332	2,331,697	2,369,527	2,328,518
Diluted	2,388,781	2,349,428	2,388,258	2,338,909
Dividends per share:	$ 0.25	$ 0.25	$ 1.75	$ 0.75