Loans payable - Narrative (Details) - Nov. 20, 2020 - SIF Loan $ in Millions, $ in Millions	USD ($)	CAD ($)
Debt Instrument [Line Items]
Face amount		$ 40.0
Term	15 years
Repayment benchmark year, revenue	$ 70.0
Repayment benchmark year, period	14 years	14 years
Discount percentage	26.00%	26.00%

Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant