Segments and Information about Revenues by Geographic Region (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Segment Reporting Information [Line Items]    
Revenues $ 74,551 $ 40,018
United States and Canada
   
Segment Reporting Information [Line Items]    
Revenues 57,766 32,572
International [Member]
   
Segment Reporting Information [Line Items]    
Revenues $ 16,785 $ 7,446