Fair value measurement - Financial assets measured at fair value (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 271,596	$ 215,301
Unrealized Gain		57
Fair Value	271,596	215,358
Level 1 \| Money market funds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	271,596	46,987
Fair Value	$ 271,596	46,987
Level 2 \| U.S. Treasury securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost		94,379
Unrealized Gain		40
Fair Value		94,419
Level 2 \| Marketable securities (U.S. treasury securities)
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost		73,935
Unrealized Gain		17
Fair Value		$ 73,952

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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