Stock compensation plans - Stock-based compensation expense and unrecognized compensation cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,713	$ 2,620	$ 5,279	$ 4,995
Unrecognized compensation	9,938		$ 9,938
Period for recognition			2 years 2 months 12 days
Employee Stock Option [Member] | Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	93	83	$ 167	169
Employee Stock Option [Member] | Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	2,201	2,186	4,341	4,108
Employee Stock Option [Member] | Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	419	$ 351	771	$ 718
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation	$ 12,259		$ 12,259
Period for recognition			3 years