Stock-based compensation - Summary of stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Mar. 07, 2024	Dec. 31, 2024	Dec. 31, 2023
2020 Stock Option and Incentive Plan
Number of Options
Options outstanding, beginning balance (in shares)		9,475,009
Options granted (in shares)		3,262,687
Options exercised (in shares)		(149,818)
Options forfeited/expired (in shares)		(1,079,728)
Options outstanding, ending balance (in shares)		11,508,150	9,475,009
Options exercisable (in shares)		5,579,212
Options vested and expected to vest (in shares)		11,508,150
Weighted-Average Exercise Price
Options outstanding, beginning balance (in dollars per share)		$ 14.34
Options granted (in dollars per share)	$ 22.00	6.83
Options exercised (in dollars per share)		5.19
Options forfeited/expired (in dollars per share)		17.82
Options outstanding, ending balance (in dollars per share)		12.00	$ 14.34
Options exercisable (in dollars per share)		17.81
Options vested and expected to vest (in dollars per share)		$ 12.00
Options, Additional Disclosures
Weighted average remaining contractual term, outstanding		7 years 8 months 12 days	7 years 7 months 9 days
Weighted average remaining contractual term, exercisable		6 years 7 months 28 days
Weighted average remaining contractual term, vested and expected to vest		7 years 8 months 12 days
Aggregate intrinsic value, outstanding		$ 2,877	$ 8,261
Aggregate intrinsic value, exercisable		150
Aggregate intrinsic value, vested and expected to vest		$ 2,877
Inducement Grants
Number of Options
Options outstanding, beginning balance (in shares)		351,000
Options granted (in shares)		639,360
Options exercised (in shares)		0
Options forfeited/expired (in shares)		0
Options outstanding, ending balance (in shares)		990,360	351,000
Options exercisable (in shares)		109,687
Options vested and expected to vest (in shares)		990,360
Weighted-Average Exercise Price
Options outstanding, beginning balance (in dollars per share)		$ 3.49
Options granted (in dollars per share)		6.00
Options exercised (in dollars per share)		0
Options forfeited/expired (in dollars per share)		0
Options outstanding, ending balance (in dollars per share)		5.11	$ 3.49
Options exercisable (in dollars per share)		3.49
Options vested and expected to vest (in dollars per share)		$ 5.11
Options, Additional Disclosures
Weighted average remaining contractual term, outstanding		9 years 3 months 10 days	9 years 6 months 10 days
Weighted average remaining contractual term, exercisable		8 years 6 months 7 days
Weighted average remaining contractual term, vested and expected to vest		9 years 3 months 10 days
Aggregate intrinsic value, outstanding		$ 40	$ 759,150
Aggregate intrinsic value, exercisable		12
Aggregate intrinsic value, vested and expected to vest		$ 40