Note 13 - Equity-based Compensation - Summary of Stock-based Compensation Expense Included in Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Stock-based compensation expense	$ 57	$ 114
Research and Development Expense [Member]
Stock-based compensation expense	7	11
Selling and Marketing Expense [Member]
Stock-based compensation expense	9	19
General and Administrative Expense [Member]
Stock-based compensation expense	$ 41	$ 84

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

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