Property and Equipment - Net (Details Textual) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Property and Equipment - Net (Textual) [Abstract]    
Property and equipment-gross $ 21,177 $ 17,113
Accumulated depreciation of equipment 10,421 8,812
Capital Lease Obligations [Member]
   
Property and Equipment - Net (Textual) [Abstract]    
Accumulated depreciation of equipment 1,205 687
Computer equipment [Member]
   
Property and Equipment - Net (Textual) [Abstract]    
Property and equipment-gross 16,275 13,032
Computer equipment [Member] | Capital Lease Obligations [Member]
   
Property and Equipment - Net (Textual) [Abstract]    
Property and equipment-gross $ 5,907 $ 3,442