Fair value measurement - Narrative (Details) - USD ($) $ in Thousands		9 Months Ended
	Jul. 18, 2025	Sep. 30, 2025	Sep. 30, 2024
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment in convertible promissory note		$ 2,000	$ 0
Convertible Promissory Note
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment in convertible promissory note	$ 2,000
Debt instrument, face amount		$ 2,000