Income taxes - Schedule of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Oct. 31, 2022	Oct. 31, 2021
Deferred tax assets
Tax losses and credits carryforwards	$ 82.6	$ 50.8	$ 48.6	$ 14.3
Share issuance costs	6.6	9.4	10.1	12.6
Convertible debt	0.0	0.0	0.0	0.0
Reserves and provisions	0.1	0.1	0.1	0.2
Other	2.8	4.0	3.4	0.1
Right of use assets, net of lease liabilities	0.9	0.5	0.5	0.5
Deferred income tax assets	93.0	64.8	62.7	27.7
Less valuation allowance	(68.9)	(42.7)	(43.9)	(25.0)
Deferred tax assets, net of valuation allowance	24.1	22.1	18.8	2.7
Deferred tax liabilities
Property, plant and equipment, due to differences in amortization	(8.0)	(9.2)	(11.2)	(2.7)
Convertible debt, due to differences in amortization	(16.1)	(12.9)	(7.6)	0.0
Deferred tax liabilities, net of valuation allowance	(24.1)	(22.1)	(18.8)	(2.7)
Net deferred income tax assets (liabilities)	$ 0.0	$ 0.0	$ 0.0	$ 0.0