Note 11 - Stockholders' Equity - Stock-based Compensation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stock-based compensation	$ 267,000	$ 2,560,000
Cost of Sales [Member]
Stock-based compensation	18,000	17,000
Selling, General and Administrative Expenses [Member]
Stock-based compensation	229,000	2,275,000
Research and Development Expense [Member]
Stock-based compensation	$ 20,000	$ 268,000