Note G - Economic Dependency - Substantial Net Sales to Certain Customers (Details) - USD ($)	3 Months Ended				9 Months Ended
	Mar. 31, 2021		Mar. 31, 2020		Mar. 31, 2021		Mar. 31, 2020
Net sales	$ 46,320,000		$ 25,482,000		$ 134,129,000		$ 83,780,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Net sales	29,026,000		16,870,000		88,289,000		53,155,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Customer 1 [Member]
Net sales	23,215,000		9,271,000		72,001,000		36,047,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Customer 2 [Member]
Net sales	5,811,000			[1]		[1]		[1]
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Customer 3 [Member]
Net sales		[1]	$ 7,599		$ 16,288		$ 17,108

[1] Sales were less than 10% of the respective period's total net sales