Note 13 - Equity-based Compensation - Summary of Stock-based Compensation Expense Included in Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock-based compensation expense	$ 224	$ 176	$ 702	$ 359
Research and Development Expense [Member]
Stock-based compensation expense	2	8	8	22
Selling and Marketing Expense [Member]
Stock-based compensation expense	53	29	118	49
General and Administrative Expense [Member]
Stock-based compensation expense	$ 169	$ 139	$ 576	$ 288

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

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