Note 12 - Revenues (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Aug. 30, 2019
Contract with Customer, Liability, Revenue Recognized	$ 719,000	$ 608,000
Contract with Customer, Liability, Current	782,000	719,000
Contract with Customer, Liability, Noncurrent	911,000	1,244,000
Distribution Agreement with AXP Distributor in China [Member]
Proceeds from Customers	82,000	41,000
Exclusivity Fee [Member]
Contract with Customer, Liability, Current	$ 286,000	$ 286,000
Contract with Customer, Liability, Total			$ 2,000,000