Fair Value Measurements - Significant inputs and assumptions (Details)	Mar. 31, 2020	Dec. 31, 2019
Black-Scholes Merton model | Risk free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration liability, measurement input	0.1	1.6
Black-Scholes Merton model | Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration liability, measurement input	30	30
Black-Scholes Merton model | Expected term
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration liability, measurement input	0.08	0.25
Black-Scholes Merton model | Expected dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration liability, measurement input	0	0
Scenario-based method | Weighted-average cost of capital
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration liability, measurement input		15.0