Revolving Facility (Details) - Revolving Facility - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Oct. 13, 2018
Nov. 02, 2017
Sep. 30, 2017
Sep. 30, 2017
Dec. 31, 2016
Nov. 02, 2015
Line of Credit Facility [Line Items]            
Maximum line of credit capacity           $ 7,500
Interest rate above the otherwise applicable rate upon default of the credit facility   5.00%        
Credit facility commitment fee   $ 38        
Net borrowings on line of credit     $ 700 $ 700    
Amount outstanding under the credit facility     700 700 $ 1,300  
Unused availability     $ 3,400 $ 3,400 $ 1,000  
Subsequent Event            
Line of Credit Facility [Line Items]            
Credit facility commitment fee $ 18          
Subsequent Event | Minimum | Prime Rate            
Line of Credit Facility [Line Items]            
Debt Instrument, Basis Spread on Variable Rate   1.75%        
Subsequent Event | Maximum | Prime Rate            
Line of Credit Facility [Line Items]            
Debt Instrument, Basis Spread on Variable Rate   2.75%        
Stated interest rate   4.50%