Leases (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Rent expense	$ 1.0	$ 0.6	$ 2.7	$ 1.8
Variable lease payments	$ 0.6	$ 0.4	$ 1.7	$ 1.0
Building
Lessee, Lease, Description [Line Items]
Term of lease	7 years		7 years
Future minimum payments due	$ 4.0		$ 4.0