Stock compensation plans - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Weighted-average assumptions:
Expected dividend yield			0.00%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted to employees			$ 3,286	$ 7,325
Options granted			1,155,217	1,467,154
Options granted, weighted average fair value per share			$ 2.84	$ 4.99
Options granted, weighted average exercise price per share			$ 4.12	$ 9.17
Weighted-average assumptions:
Weighted-average risk-free interest rate	4.30%	3.70%	4.30%	3.80%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected volatility	77.00%	54.30%	76.10%	53.50%
Expected term	5 years 6 months	5 years 7 months 6 days	5 years 10 months 24 days	5 years 10 months 24 days