Leases - Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Leases
Total lease costs	$ 0.1	$ 0.1	$ 0.4	$ 0.4
Weighted-average incremental borrowing rate used to determine right-of-use assets and lease liabilities	11.00%		11.00%
Impairment losses of ROU assets			$ 0.0		$ 0.0
Maximum
Leases
Short-term operating lease costs	$ 0.1	$ 0.1	$ 0.1	$ 0.1