Fair value measurement - Valuation technique and inputs used in determining the fair value of contingent consideration (Details)	Sep. 27, 2020
Milestone-based payments | Minimum | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.025
Milestone-based payments | Maximum | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.033
Milestone-based payments | Weighted Average | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.030
Revenue-based payments | Monte Carlo simulation | Revenue volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.220
Revenue-based payments | Minimum | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.022
Revenue-based payments | Maximum | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.100
Revenue-based payments | Weighted Average | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, liability, measurement input	0.089