Note 11 - Financial Information about Geographic Areas - Consolidated Net Sales and Long-lived Asset Information by Geographic Area (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Revenues	$ 16,115,000	$ 17,373,000	$ 29,914,000	$ 35,034,000
Reportable Geographical Components [Member]
Long-lived assets	5,671,000		5,671,000		$ 5,742,000
UNITED STATES | Reportable Geographical Components [Member]
Revenues	16,061,000	16,740,000	29,754,000	33,815,000
Long-lived assets	4,384,000		4,384,000		4,380,000
International Member | Reportable Geographical Components [Member]
Revenues	54,000	$ 633,000	160,000	$ 1,219,000
Long-lived assets	$ 1,287,000		$ 1,287,000		$ 1,362,000