Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.6.0.2
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2014
Sep. 30, 2016
Dec. 31, 2015
Accounting Policies [Line Items]        
Percentage of tax benefit likely of being realized 50.00%      
Restricted Cash and Cash Equivalents $ 15,900,000     $ 14,600,000
Gain (Loss) on Sale of Assets and Asset Impairment Charges   $ 400,000    
Allowance for Doubtful Accounts Receivable $ 0     0
Debt Instrument, Interest Rate, Stated Percentage 39.00%      
Deferred Revenue and Credits, Current $ 995,000     0
Elimination Of Revenue 1,300,000      
Pledged Assets Separately Reported, Loans Pledged as Collateral, at Fair Value 600,000     600,000
Deferred Clearing [Member]        
Accounting Policies [Line Items]        
Deferred Revenue and Credits, Current     $ 700,000  
Marketing Credits [Member]        
Accounting Policies [Line Items]        
Deferred Revenue and Credits, Current     $ 300,000  
Hercules Note Payble [Member]        
Accounting Policies [Line Items]        
Restricted Cash and Cash Equivalents $ 14,900,000     $ 14,000,000