Stock compensation plans - Stock-based compensation expense and unrecognized compensation cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,566	$ 2,375
Unrecognized compensation	$ 11,778
Period for recognition	2 years 4 months 24 days
Employee Stock Option [Member] | Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 74	86
Employee Stock Option [Member] | Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	2,140	1,922
Employee Stock Option [Member] | Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	352	$ 367
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation	$ 13,644
Period for recognition	3 years 2 months 12 days