Note 12 - Stockholders' Equity - Stock-based Compensation (Details) - USD ($)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Stock-based compensation	$ 2,560,000	$ 880,000
Cost of Sales [Member]
Stock-based compensation	17,000	9,000
Selling, General and Administrative Expenses [Member]
Stock-based compensation	2,275,000	757,000
Research and Development Expense [Member]
Stock-based compensation	$ 268,000	$ 114,000

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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