Financial instruments fair value - Fair value of financial instruments (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	$ 146,037	$ 125,000
Total contingent consideration	10,100	8,200
Accrued liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	4,588
Other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	5,512	8,200
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	146,037	125,000
Total contingent consideration	0	0
Level 1 | Accrued liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	0
Level 1 | Other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	0	0
Total contingent consideration	0	0
Level 2 | Accrued liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	0
Level 2 | Other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	0	0
Total contingent consideration	10,100	8,200
Level 3 | Accrued liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	4,588
Level 3 | Other liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total contingent consideration	5,512	8,200
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	146,037	100,000
Money market funds | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	146,037	100,000
Money market funds | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	0	0
Money market funds | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents	$ 0	0
U.S. Treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents		25,000
U.S. Treasuries | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents		25,000
U.S. Treasuries | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents		0
U.S. Treasuries | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash equivalents		$ 0