Income taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Current
Federal	$ 0	$ 0
Deferred
Federal	(8,170)	(13,786)
Change in Valuation Allowance	8,170	13,786
Income tax expense (benefit)	$ 0	$ 0