Income Taxes (Carryforward) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Reconciliation of the changes in the gross balance of unrecognized tax benefits, excluding interest and penalties      
Balance at the beginning of the period $ 3,583 $ 3,583 $ 2,943
Current year additions 640
Balance at the end of the period 3,583 3,583 $ 3,583
Additional unrecognized tax benefits 0 $ 0  
Change in unrecognized tax benefits 0    
Unrecognized tax benefits that would, if recognized, impact the Company's effective income tax rate 3,600    
Undistributed foreign earning 300    
Unrecognized deferred tax liabilities from temporary differences related to the investment in foreign subsidiary that would have been taxable if the Company repatriated the foreign earnings 100    
State      
Net operating loss and tax credit carryforwards      
Net operating losses 60,952    
Tax credit carryforwards 2,799    
Unrecorded tax benefits for stock-based compensation 17,600    
Foreign      
Net operating loss and tax credit carryforwards      
Net operating losses 2,699    
Federal      
Net operating loss and tax credit carryforwards      
Net operating losses 59,457    
Tax credit carryforwards 7,135    
Unrecorded tax benefits for stock-based compensation $ 20,600