Note 12 - Revenues (Details Textual)		12 Months Ended
	Aug. 30, 2019 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Contract with Customer, Liability, Revenue Recognized		$ 782,000	$ 719,000
Contract with Customer, Liability, Current		670,000	782,000
Contract with Customer, Liability, Noncurrent		127,000	911,000
Exclusivity Fee [Member]
Contract with Customer, Liability, Revenue Recognized		781,000	286,000
Contract with Customer, Liability	$ 2,000,000
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price		495,000
Supply Agreement [Member]
Supply Agreement, Term	5 years
Supply Agreement, Renewal Term, Number of Options	2
Supply Agreement, Renewal Term, Per Option	2 years
Distribution Agreement with AXP Distributor in China [Member]
Proceeds from Customers		$ 82,000	$ 82,000
Minimum [Member]
Period Of Warranty On Products		1 year
Maximum [Member]
Period Of Warranty On Products		2 years
Maximum [Member] | Supply Agreement [Member]
Supply Agreement, Renewal Term	4 years