Stock-based compensation - Narrative (Details)				3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 08, 2024 USD ($) peer $ / shares shares	Jan. 03, 2023 USD ($) peer shares	Feb. 24, 2022 USD ($) peer shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Dec. 31, 2023 USD ($) $ / shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Aggregate intrinsic value of exercisable service vesting-based stock options				$ 3,600,000		$ 3,600,000
Intrinsic value of service vesting-based awards exercised				$ 500,000		$ 1,100,000
Service based-vesting options granted (in shares) | shares				0		0
Weighted average remaining contractual life (year)						1 year 6 months
Share-based payment arrangement, expense				$ 5,324,000	$ 7,984,000	$ 16,022,000	$ 19,715,000
Number of peers | peer	20	20	20
Comprehensive loss				(1,356,000)	$ (29,293,000)	$ (32,506,000)	$ (53,026,000)
Vesting period (year)						4 years
Adjustment
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Comprehensive loss								$ (1,600,000)
Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation costs for service vesting-based stock options				0		$ 0
Restricted Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation costs for service vesting-based stock options				26,800,000		26,800,000
Aggregate fair value of the service vesting-based awards granted				6,700,000		10,000,000.0
Aggregate fair value of the service vesting-based awards that vested				2,300,000		8,000,000.0
Share-based payment arrangement, expense				$ 3,800,000		$ 11,700,000
Period for recognition (year)						2 years 8 months 12 days
Granted (in shares) | shares						484,886
Grant date fair value (in dollars per share) | $ / shares				$ 16.22		$ 16.22		$ 18.32
Vested (in shares) | shares						701,436
Performance Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation costs for service vesting-based stock options				$ 1,200,000		$ 1,200,000
Service based-vesting options granted (in shares) | shares					0		0
Share-based payment arrangement, expense				200,000		$ 700,000
Period for recognition (year)						1 year 2 months 12 days
Granted (in shares) | shares	109,512
Grant date fair value (in dollars per share) | $ / shares	$ 17.36
Aggregate fair value of the market-based awards granted				$ 1,900,000		$ 1,900,000
Vested (in shares) | shares				0		0
Market-based Restricted Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation costs for service vesting-based stock options				$ 4,400,000		$ 4,400,000
Share-based payment arrangement, expense				$ 1,300,000	$ 1,600,000	$ 3,700,000	$ 4,900,000
Period for recognition (year)						1 year 1 month 6 days
Granted (in shares) | shares	300,529					299,565
Grant date fair value (in dollars per share) | $ / shares				$ 25.70		$ 25.70		$ 26.50
Aggregate fair value of the market-based awards granted				$ 0	0	$ 6,300,000	6,500,000
Vested (in shares) | shares						300,529
Total shareholder return attainment (percent)	125.00%
Historical volatility (percent)	80.00%	78.00%	63.00%
Dividend yield (percent)	0.00%	0.00%	0.00%
Risk-free interest rate	4.60%	4.40%	1.50%
Measurement date with a maturity period (year)	2 years	2 years	2 years
Aggregate fair value of the market-based awards that vested				$ 0	$ 0	$ 5,100,000	$ 700,000
Market-based Restricted Stock | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total shareholder return attainment (percent)	0.00%	0.00%
Market-based Restricted Stock | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total shareholder return attainment (percent)	200.00%	200.00%
Market-based Restricted Stock | Executive Officer
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based payment arrangement, expense	$ 6,300,000	$ 6,800,000	$ 6,700,000
Granted (in shares) | shares	239,464	268,738	240,428