Description of Business and Summary of Significant Accounting Policies (Inventory) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Inventories      
Inventory write-downs $ 2,300 $ 1,700 $ 2,300
Gain on inventory purchase commitment     $ 380