Fair value measurement - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]
Cash equivalents	$ 2,800,000
Marketable securities		$ 1,300,000
Impairment for Marketable Securities	0	0
Impairment for Accrued Interest Receivable	$ 0	$ 0
Maximum
Debt Securities, Available-for-Sale [Line Items]
Contractual maturities	7 months
Minimum
Debt Securities, Available-for-Sale [Line Items]
Contractual maturities	1 month