Note 9 - Controlled Launch (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Feb. 28, 2021
Number of KOLs			70
Controlled Launch, Program Expenses	$ 0	$ 300
Revenue from Contract with Customer, Excluding Assessed Tax	0	444
Redemption of Non Cash Credits [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 0	$ 300
Minimum [Member]
Number of Patients Participating in Procedure			40
Maximum [Member]
Number of Patients Participating in Procedure			50