Note 3 - Revenue From Contracts With Customers - Changes in Contract Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Total deferred revenue related to contracts with customers, beginning of period	$ 700,000	$ 700,000
Deferred revenue related to milestones achieved	100,000	0
Deferred revenue related to milestones achieved, written off due to contract renegotiations	(100,000)	0
Total deferred revenue related to contracts with customers, end of period	$ 700,000	$ 700,000