Description of Business and Summary of Significant Accounting Policies (Recent Accounting Pronouncements) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Jan. 01, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Deferred tax assets, operating loss carryforwards   $ 15,357 $ 22,076  
Increase in net valuation allowance   (11,400) (800)  
Net cash provided by operating activities   17,866 4,414 $ 11,248
Net cash provided by (used in) financing activities   (718) $ (8,575) $ 5,364
Accounting Standards Update 2016-09 | Adjustment        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Net cash provided by operating activities   100    
Net cash provided by (used in) financing activities   (100)    
Accumulated Deficit | Accounting Standards Update 2016-09 | Adjustment        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
New accounting pronouncement, cumulative effect of change, accumulated deficit increase (decrease) $ 300      
State        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Unrecorded tax benefits for stock-based compensation   17,600    
Domestic | Accounting Standards Update 2016-09 | Adjustment        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Deferred tax assets, operating loss carryforwards 7,700      
Domestic | Accounting Standards Update 2016-09 | Valuation allowance, operating loss carryforwards | Adjustment        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Increase in net valuation allowance 7,700      
Domestic | Accumulated Deficit | Accounting Standards Update 2016-09 | Adjustment        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
New accounting pronouncement, cumulative effect of change, accumulated deficit increase (decrease) (7,700)      
Domestic | Accumulated Deficit | Accounting Standards Update 2016-09 | Valuation allowance, operating loss carryforwards | Adjustment        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
New accounting pronouncement, cumulative effect of change, accumulated deficit increase (decrease) $ 7,700      
Federal        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Unrecorded tax benefits for stock-based compensation   $ 20,600