Income taxes - Reconciliation (Details) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax at federal statutory rate		$ (14,224,000)	$ 7,234,000	$ 18,921,000
Tax at federal statutory rate		21.00%	21.00%	21.00%
Change in valuation allowance		$ 0	$ 0	$ (284,551,000)
Change in valuation allowance		0.00%	0.00%	(315.80%)
Impact of foreign operations		$ 2,969,000	$ 1,572,000	$ (8,222,000)
Impact of foreign operations		(4.40%)	4.60%	(9.20%)
Stock-based compensation		$ 3,434,000	$ (1,192,000)	$ (5,345,000)
Stock-based compensation		5.10%	3.50%	5.90%
State taxes, net of federal benefits		$ (1,560,000)	$ 1,189,000	$ 1,828,000
State taxes, net of federal benefits		2.30%	3.50%	2.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Amount		$ 5,474,000	$ 5,222,000	$ 6,091,000
Effective Income Tax Rate Reconciliation, Tax Credit, Percent		(8.10%)	15.10%	6.80%
Other		$ (252,000)	$ 220,000	$ 705,000
Other		0.40%	0.60%	0.80%
Income tax (benefit) expense		$ (14,550,000)	$ 5,606,000	$ (281,071,000)
Effective tax rate	16.30%	21.50%	16.30%	(312.00%)

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference, between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, that is attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority interest income (expense), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, change in enacted tax rate, prior year income taxes, change in deferred tax asset valuation allowance, and other adjustments.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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