Note 2 - Summary of Significant Accounting Policies - Customer Contract Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Customer contract liabilities	$ 17,000	$ 108,000
Change in customer contract liabilities	(91,000)
Marketing Programs [Member]
Customer contract liabilities	17,000	$ 108,000
Change in customer contract liabilities	$ (91,000)