Information About Segment and Geographic Areas (Tables)
6 Months Ended
Jun. 30, 2012
Information About Segment and Geographic Areas [Abstract]  
Schedule of revenue and long-lived tangible assets by geographic area
                                 
    Three Months Ended
June 30,
    Six Months Ended
June 30,
 
    2011     2012     2011     2012  

Revenue

                               

United States

  $ 19,303     $ 30,641     $ 37,836     $ 61,155  

United Kingdom

    164       166       325       322  
   

 

 

   

 

 

   

 

 

   

 

 

 

Total revenue

  $ 19,467     $ 30,807     $ 38,161     $ 61,477  
   

 

 

   

 

 

   

 

 

   

 

 

 

 

                 
    December 31,
2011
    June 30,
2012
 

Long-lived tangible assets

               

United States

  $ 7,680     $ 10,245  

Netherlands

    621       511  
   

 

 

   

 

 

 

Total long-lived tangible assets

  $ 8,301     $ 10,756