Note 15 - Activity of Business Segments - Consolidated Net Sales and Long-lived Asset Information by Geographic Area (Details) - Reportable Geographical Components [Member] - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Net sales by geographic region
Consolidated sales	$ 102,700,000	$ 46,665,000
Long-lived assets by geographic region
Consolidated long-lived assets	4,353,000	3,943,000
UNITED STATES
Net sales by geographic region
Consolidated sales	90,495,000	45,748,000
Long-lived assets by geographic region
Consolidated long-lived assets	2,787,000	2,450,000
International Member
Net sales by geographic region
Consolidated sales	12,205,000	917,000
Long-lived assets by geographic region
Consolidated long-lived assets	$ 1,566,000	$ 1,493,000