Line of Credit - Additional Information (Detail)
12 Months Ended
Dec. 31, 2016
USD ($)
Jul. 31, 2014
USD ($)
Mar. 31, 2013
USD ($)
Line of Credit Facility [Line Items]      
Draws against the facility $ 0    
Line of credit facility, remaining borrowing capacity available $ 5,000,000    
Liquidity and debt ratios required under debt covenant 1.5    
Revolving credit facility expiring June 2016 [Member]      
Line of Credit Facility [Line Items]      
Line of credit facility, maximum credit availability     $ 6,500,000.0
Revolving credit facility expiring June 2016 [Member] | London Inter Bank Offer Rate [Member]      
Line of Credit Facility [Line Items]      
Basis spread for interest (as percent) 1.75%    
Revolving credit facility expiring June 2016 [Member] | Prime rate [Member]      
Line of Credit Facility [Line Items]      
Basis spread for interest (as percent) 0.75%    
Letter of credit [Member]      
Line of Credit Facility [Line Items]      
Interest rate on letter of credit (as percent) 1.50%    
Letter of credit [Member] | Lease Amendment [Member]      
Line of Credit Facility [Line Items]      
Letter of credit   $ 1,500,000.0