CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 9,876,000	$ 10,420,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,267,000	1,118,000
Loss on marketable securities	42,000
(Recovery of) provision for doubtful accounts	(130,000)	238,000
Deferred income taxes	55,000	577,000
Stock-based compensation expense	272,000	497,000
Changes in operating assets and liabilities:
Accounts receivable	707,000	2,386,000
Inventories	5,749,000	(7,799,000)
Prepaid expenses and other current assets	165,000	(39,000)
Accounts payable, accrued expenses, accrued salaries and wages, accrued income taxes	(1,572,000)	(784,000)
Net Cash Provided by Operating Activities	16,431,000	6,614,000
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property, plant, and equipment	(566,000)	(1,325,000)
Purchases of marketable securities	(5,403,000)
Net Cash Used in Investing Activities	(5,969,000)	(1,325,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from stock option exercises		71,000
Cash paid for purchase of treasury stock		(2,350,000)
Net Cash Used in Financing Activities		(2,279,000)
Net Change in Cash and Cash Equivalents	10,462,000	3,012,000
CASH AND CASH EQUIVALENTS - Beginning	18,248,000	8,028,000
CASH AND CASH EQUIVALENTS - Ending	28,710,000	11,040,000
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid	14,000	24,000
Income taxes paid	$ 1,847,000	$ 735,000