Fair value measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair value measurements
Marketable securities	$ 34,523	$ 151,827
U.S. treasury securities
Fair value measurements
Marketable securities	29,548	107,810
U.S government agency securities
Fair value measurements
Marketable securities	4,975	44,017
Recurring basis
Fair value measurements
Cash equivalents	115,538	60,464
Marketable securities	34,523	151,827
Recurring basis | Quoted Prices in Active Markets (Level 1)
Fair value measurements
Cash equivalents	115,538	50,471
Marketable securities	29,548	107,810
Recurring basis | Significant Other Observable Inputs (Level 2)
Fair value measurements
Cash equivalents	0	9,993
Marketable securities	4,975	44,017
Recurring basis | Significant Unobservable Inputs (Level 3)
Fair value measurements
Cash equivalents	0	0
Marketable securities	0	0
Recurring basis | Money market funds
Fair value measurements
Cash equivalents	90,649	50,471
Recurring basis | Money market funds | Quoted Prices in Active Markets (Level 1)
Fair value measurements
Cash equivalents	90,649	50,471
Recurring basis | Money market funds | Significant Other Observable Inputs (Level 2)
Fair value measurements
Cash equivalents	0	0
Recurring basis | Money market funds | Significant Unobservable Inputs (Level 3)
Fair value measurements
Cash equivalents	0	0
Recurring basis | U.S. treasury securities
Fair value measurements
Cash equivalents	24,889
Marketable securities	29,548	107,810
Recurring basis | U.S. treasury securities | Quoted Prices in Active Markets (Level 1)
Fair value measurements
Cash equivalents	24,889
Marketable securities	29,548	107,810
Recurring basis | U.S. treasury securities | Significant Other Observable Inputs (Level 2)
Fair value measurements
Cash equivalents	0
Marketable securities	0	0
Recurring basis | U.S. treasury securities | Significant Unobservable Inputs (Level 3)
Fair value measurements
Cash equivalents	0
Marketable securities	0	0
Recurring basis | U.S government agency securities
Fair value measurements
Cash equivalents		9,993
Marketable securities	4,975	44,017
Recurring basis | U.S government agency securities | Quoted Prices in Active Markets (Level 1)
Fair value measurements
Cash equivalents		0
Marketable securities	0	0
Recurring basis | U.S government agency securities | Significant Other Observable Inputs (Level 2)
Fair value measurements
Cash equivalents		9,993
Marketable securities	4,975	44,017
Recurring basis | U.S government agency securities | Significant Unobservable Inputs (Level 3)
Fair value measurements
Cash equivalents		0
Marketable securities	$ 0	$ 0