Business acquisition - Narrative (Details) - USD ($)
 12 Months Ended
Feb. 28, 2021
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Nov. 27, 2020
Business Acquisition [Line Items]          
Amortization of intangible assets   $ 2,322,000 $ 1,933,000 $ 0  
Netless          
Business Acquisition [Line Items]          
Business acquisition, percentage of voting interests acquired         100.00%
Total purchase consideration       4,000,000 $ 4,000,000.0
Intangible assets, net       $ 213,000  
Finite-lived intangible asset, useful life       5 years  
Netless | Developed Technology [Member] | General and Administrative Expense [Member]          
Business Acquisition [Line Items]          
Amortization of intangible assets   42,600 42,600 $ 3,500  
Acquisition Of Easemob [Member]          
Business Acquisition [Line Items]          
Business acquisition, percentage of voting interests acquired 100.00%        
Total purchase consideration $ 53,400,000   53,350,000    
Intangible assets, net     8,155,000    
Acquisition Of Easemob [Member] | Customer Relationships [Member]          
Business Acquisition [Line Items]          
Intangible assets, net $ 4,200,000        
Finite-lived intangible asset, useful life 3 years        
Acquisition Of Easemob [Member] | Customer Relationships [Member] | Selling and Marketing Expense [Member]          
Business Acquisition [Line Items]          
Amortization of intangible assets   1,400,000 1,200,000    
Acquisition Of Easemob [Member] | Customer Relationships [Member] | General and Administrative Expense [Member]          
Business Acquisition [Line Items]          
Amortization of intangible assets   800,000 $ 700,000    
Acquisition Of Easemob [Member] | Developed Technology [Member]          
Business Acquisition [Line Items]          
Intangible assets, net   $ 4,000,000.0      
Finite-lived intangible asset, useful life   5 years