Fair value measurements - Assets and liabilities measured on a recurring basis - (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Assets, Fair Value Disclosure [Abstract]
Money market funds included in cash and cash equivalents	$ 71,367	$ 68,802
Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Total money market funds and marketable securities	320,679	227,663
Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Total money market funds and marketable securities	212,959	199,708
Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Total money market funds and marketable securities	107,720	27,955
U.S. Treasury notes | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	125,783	103,044
U.S. Treasury notes | Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	125,783	103,044
U. S. Government agency securities | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	27,518	31,075
U. S. Government agency securities | Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	27,518	31,075
Certificates of deposit | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	4,286
Certificates of deposit | Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	4,286
Corporate bonds | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	94,976	23,970
Corporate bonds | Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	94,976	23,970
Commercial paper | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	8,458	3,985
Commercial paper | Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	8,458	3,985
Money market funds
Assets, Fair Value Disclosure [Abstract]
Money market funds included in cash and cash equivalents	59,658	65,589
Money market funds | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Money market funds included in cash and cash equivalents	59,658	65,589
Money market funds | Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Money market funds included in cash and cash equivalents	$ 59,658	$ 65,589