Commitments and Contingencies - Lease Cost and Terms (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 1.2	$ 2.2	$ 2.2
Short-term lease cost	0.9	0.5	0.0
Variable lease cost	0.1	0.2	0.2
Sublease income	0.0	0.0	(0.3)
Total lease cost	2.2	2.9	2.1
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for operating leases	$ 1.8	$ 2.1	$ 1.6