Note 11 - Financial Information about Geographic Areas - Consolidated Net Sales and Long-lived Asset Information by Geographic Area (Details) - USD ($)	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Revenues	$ 13,482,000	$ 13,800,000
Reportable Geographical Components [Member]
Long-lived assets	5,426,000		$ 5,587,000
UNITED STATES \| Reportable Geographical Components [Member]
Revenues	13,298,000	13,694,000
Long-lived assets	4,214,000		4,340,000
International Member \| Reportable Geographical Components [Member]
Revenues	184,000	$ 106,000
Long-lived assets	$ 1,212,000		$ 1,247,000

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details