Principal Accounting Policies - Property and Equipment, Net (Details)
12 Months Ended
Dec. 31, 2021
Electronic equipment  
Property, Plant and Equipment [Line Items]  
Property equipment, useful life 3 years
Furniture, computers and office equipment  
Property, Plant and Equipment [Line Items]  
Property equipment, useful life 3 years
Network equipment  
Property, Plant and Equipment [Line Items]  
Property equipment, useful life 3 years
Leasehold Improvements [Member]  
Property, Plant and Equipment [Line Items]  
Property, equipment estimated useful ife Shorter of the lease term or the estimated useful life
Software Development [Member] | Maximum [Member]  
Property, Plant and Equipment [Line Items]  
Property, equipment estimated useful ife 5
Software Development [Member] | Minimum [Member]  
Property, Plant and Equipment [Line Items]  
Property, equipment estimated useful ife 3