Income tax Income tax (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$ 100,000,000	$ 98,000,000
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	0
Deferred Tax Assets, Other Tax Carryforwards	$ 9,000,000