Note F - Debt (Details Textual)			3 Months Ended		15 Months Ended
	Aug. 20, 2021 USD ($)	Aug. 18, 2021 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Aug. 23, 2021	Jun. 30, 2021 USD ($)	May 24, 2021 USD ($)	Jan. 31, 2021 USD ($)
Payments to Acquire Property, Plant, and Equipment, Total			$ 1,278,000	$ 7,767,000
Interest Rate Swap [Member]
Derivative, Fixed Interest Rate		2.40%							2.40%
Manufacturing Facility and Warehouse [Member] | Carlsbad, California [Member]
Payments to Acquire Property, Plant, and Equipment, Total	$ 17,500,000
Wells Fargo Bank, N.A. [Member]
Debt Instrument, Covenant, Annual Limit To Repurchase Stock or Issue Dividends								$ 5,000,000				$ 7,000,000
Wells Fargo Bank, N.A. [Member] | Credit Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity											$ 20,000,000
Debt Instrument Covenant Capital Expenditures Limitation, Amount, Next Twelve Years							$ 15,000,000			$ 10,000,000
Debt Instrument Covenant Capital Expenditures Limitation, Amount, After Twelve Years			$ 25,000,000		$ 25,000,000	$ 25,000,000	$ 7,500,000
Debt Instrument Covenant Minimum, Net Income Required		$ 1
Debt Instrument Covenant, Fixed Charge Coverage Ratio			1.25		1.25
Long-term Debt, Percentage Bearing Fluctuating Interest, Threshold Amount		100,000
Minimum Prepayment Amount Under Line of Credit		$ 100,000
Line of Credit Facility, Commitment Fee Percentage		0.125%
Line of Credit Facility, Remaining Borrowing Capacity			$ 20,000,000		$ 20,000,000
Wells Fargo Bank, N.A. [Member] | Credit Agreement [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate					1.29%
Debt Instrument Basis Spread on Elected Fixed Rate Borrowing			1.29%		1.29%
Wells Fargo Bank, N.A. [Member] | Credit Agreement [Member] | Maximum [Member]
Ratio of Indebtedness to Net Capital		1.5
Ratio of Total Current Assets to Total Current Liabilities		1.75
Wells Fargo Bank, N.A. [Member] | Credit Agreement [Member] | Term Loan [Member]
Debt Instrument, Face Amount		$ 10,000,000
Debt Instrument, Term (Year)		7 years
Debt Instrument, Amortization Period (Year)		25 years
Long-Term Debt			$ 9,400,000		$ 9,400,000
Wells Fargo Bank, N.A. [Member] | Credit Agreement [Member] | Term Loan [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate		1.80%