Note 15 - Equity-based Compensation - Summary of Stock-based Compensation Expense Included in Results of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock-based compensation expense	$ 933	$ 532	$ 486
Research and Development Expense [Member]
Stock-based compensation expense	10	23	42
Selling and Marketing Expense [Member]
Stock-based compensation expense	129	85	93
General and Administrative Expense [Member]
Stock-based compensation expense	$ 794	$ 424	$ 351