Note 8 - Accrued Expenses and Other Liabilities - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Compensation and related expenses	$ 8,794	$ 7,345
Professional fees	2,046	3,438
Clinical trial costs	2,463	1,429
Other	2,494	1,144
Total	17,339	14,793
Accrued Expenses and Other Current Liabilities [Member]
Operating lease liability - current	$ 1,542	$ 1,437