Deferred revenue - Movement In Deferred Revenue (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Movement in Deferred Revenue [Roll Forward]
Current deferred revenue	$ 2.4	$ 0.2
Non-current deferred revenue	5.2	5.3
Product revenue
Movement in Deferred Revenue [Roll Forward]
Balance, beginning of the period	0.0	0.0
Additions	2.8	0.0
Revenue recognized	(0.6)	0.0
Balance, end of the period	2.2	0.0
Current deferred revenue	2.2	0.0
Non-current deferred revenue	0.0	0.0
Service
Movement in Deferred Revenue [Roll Forward]
Balance, beginning of the period	5.5	0.0
Additions	0.0	5.4
Foreign exchange gain (loss)	(0.1)	0.1
Balance, end of the period	5.4	5.5
Current deferred revenue	0.2	0.2
Non-current deferred revenue	$ 5.2	$ 5.3