Property and Equipment, Net
 12 Months Ended
Dec. 31, 2021
Property, Plant and Equipment [Abstract]  
Property and Equipment, Net
6.
Property and Equipment, Net
Property and equipment, net consisted of the following:
 
 
  
As of December 31,
 
 
  
2020
 
 
  
 
  
2021
 
 
  
 
 
 
 
 
  
 
 
 
  
(US$ thousand)
 
Cost:
  
      
 
      
  
      
Network equipment
    $ 19,901              $ 27,804  
Electronic equipment
      2,232                3,324  
Leasehold improvements
      1,950                2,755  
Furniture, computers and office equipment
      874                1,064  
    
 
 
             
 
 
  
Total cost
      24,957                34,947  
Less: accumulated depreciation
      (8,203 )               (16,879 )
 
Capitalized internal-use software development costs
      —                  844  
Construction in progress
      —                  282  
    
 
 
             
 
 
  
Property and equipment, ne
t
    $ 16,754              $ 19,194  
    
 
 
             
 
 
  
Depreciation expense recognized for the years ended December 31, 2019, 2020 and 2021 were US$1.9 million, US$4.5 million and US$8.3 million, respectively.