XML 51 R40.htm IDEA: XBRL DOCUMENT v3.21.1
Summary of Significant accounting policies - Intangible assets (Details)
3 Months Ended
Mar. 31, 2021
Minimum  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life (in years) 4 years
Maximum  
Acquired Finite-Lived Intangible Assets [Line Items]  
Useful life (in years) 15 years