CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net income (loss)	$ (351,500)	$ 62,200
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Gain on sale of investment	0	(3,200)
Depreciation and amortization	230,100	276,500
Deferred income tax expense	(39,400)	(7,400)
Income tax benefit of stock options exercised	8,000	0
Stock-based compensation	18,600	1,300
Change in fair value of contingent consideration	445,700	0
Changes in operating assets and liabilities:
Trade accounts receivable	(227,700)	149,600
Inventories	(740,400)	206,200
Prepaid expenses and other current assets	(12,000)	(25,900)
Accounts payable	255,200	700
Long term accounts receivable	0	(245,400)
Customer advances	356,000	107,900
Accrued expenses	(92,800)	(317,700)
Total adjustments	201,300	142,600
Net cash provided by (used in) operating activities	(150,200)	204,800
Investing activities:
Redemption of investment securities, available-for-sale	0	11,100
Purchase of investment securities, available-for-sale	(14,500)	(18,700)
Capital expenditures	(70,500)	(18,200)
Purchase of other intangible assets	(3,600)	(12,800)
Net cash used in investing activities	(88,600)	(38,600)
Financing activities:
Line of credit proceeds	40,000	250,000
Line of credit repayments	0	(250,000)
Payments for contingent consideration	(142,700)	(166,100)
Cash dividend declared and paid	0	(44,500)
Proceeds from exercise of stock options	0	15,500
Principal payments on note payable	(5,000)	(4,800)
Net cash used in financing activities	(107,700)	(199,900)
Net decrease in cash and cash equivalents	(346,500)	(33,700)
Cash and cash equivalents, beginning of year	1,025,100	1,245,000
Cash and cash equivalents, end of period	678,600	1,211,300
Cash paid during the period for:
Income taxes	16,000	213,500
Interest	$ 1,100	$ 2,200