Income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Operating Loss Carryforwards [Line Items]
Income tax expense	$ 0	$ 0
Increase in valuation allowance	45,600	$ 66,900
Federal operating loss	277,200
State net operating loss	97,000
Net operating loss generated not subject to expiration	$ 260,200
Percentage of taxable income offset from net operating loss	80.00%
R&D tax credits	$ 200
Federal
Operating Loss Carryforwards [Line Items]
Federal tax	$ 15,300