Description of Business and Summary of Significant Accounting Policies (Concentration) (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2016
USD ($)
segment
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Revenue from U.S., Canadian and all other international dealers and distributors combined      
Total revenue $ 208,802 $ 163,179 $ 148,800
International revenue (excluding Canada) as a percent of total revenue 21.00% 24.00% 24.00%
Segment Reporting      
Number of operating segments | segment 1    
United States      
Revenue from U.S., Canadian and all other international dealers and distributors combined      
Total revenue $ 148,803 $ 109,435 $ 98,276
Canada      
Revenue from U.S., Canadian and all other international dealers and distributors combined      
Total revenue 16,084 14,285 15,320
All other international sources      
Revenue from U.S., Canadian and all other international dealers and distributors combined      
Total revenue $ 43,915 $ 39,459 $ 35,204