Income taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Effective income tax rate, percent	(3.52%)	(1.51%)	(1.50%)
Valuation allowance	$ 150,915	$ 129,453
Valuation allowance increase	21,500
Research and development tax credits	28,645	20,412
Unrecognized tax benefits	7,232	5,310	$ 3,608	$ 10,580
Potential tax associated with foreign earnings being repatriated	500
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	160,600
Net operating loss carryforward subject to expiration	72,400
Net operating loss carryforward not subject to expiration	88,200
Research and development tax credits	23,200
Domestic Tax Authority | Tax Year 2010-2012
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward subject to expiration	3,400
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward		$ 41,400
Research and development tax credits	$ 15,300