Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Additional Information (Detail)

v3.6.0.2
Commitments and Contingencies - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Operating Leased Assets [Line Items]      
Lease expiration period 2022    
Maximum [Member]      
Operating Leased Assets [Line Items]      
Rent expense $ 1,000,000 $ 1,000,000 $ 1,000,000
Future gross minimum lease payments $ 1,000,000    
Lease One [Member]      
Operating Leased Assets [Line Items]      
Lease commenced date 2011-07    
Lease amended date 2013-10    
Lease Two [Member]      
Operating Leased Assets [Line Items]      
Lease commenced date 2012-03    
Lease amendment commenced date 2014-03