Controlled Launch (Narrative) (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($) item
Controlled Launch [Abstract]
Number of KOLs | item		80
Number of patients participating in procedure		40 or 50
Program expenses | $	$ 0.4	$ 0.6