Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.8.0.1
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Feb. 28, 2018
Jan. 02, 2018
Sep. 30, 2017
Sep. 30, 2016
Accounting Policies [Line Items]                
Percentage of tax benefit likely of being realized   50.00%            
Restricted Cash and Cash Equivalents   $ 17,400 $ 15,900          
Allowance for Doubtful Accounts Receivable   $ 1,300 100          
Debt Instrument, Interest Rate, Stated Percentage   28.00%            
Deferred Revenue and Credits, Current   $ 786 995          
Pledged Assets Separately Reported, Loans Pledged as Collateral, at Fair Value   2,500 1,000          
Variable Interest Entity, Measure of Activity, Expense   16,500 17,000          
Reimbursement expenses   $ 9,900 $ 11,900          
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent   35.00% 35.00% 35.00%        
Revenue Recognition, Sales Returns, Reserve for Sales Returns   $ 1,200 $ 100          
Scenario, Plan [Member]                
Accounting Policies [Line Items]                
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 21.00%              
Subsequent Event [Member]                
Accounting Policies [Line Items]                
Debt Instrument, Interest Rate, Stated Percentage         8.00%      
Cumulative Effect of New Accounting Principle in Period of Adoption           $ 800    
Held-to-maturity Securities [Member]                
Accounting Policies [Line Items]                
Time Deposits, at Carrying Value   36,000            
Cash and Cash Equivalents [Member]                
Accounting Policies [Line Items]                
Time Deposits, at Carrying Value   14,000            
Deferred Clearing [Member]                
Accounting Policies [Line Items]                
Deferred Revenue and Credits, Current             $ 500 $ 700
Marketing Credits [Member]                
Accounting Policies [Line Items]                
Deferred Revenue and Credits, Current             $ 300 $ 300
Hercules Note Payble [Member]                
Accounting Policies [Line Items]                
Restricted Cash and Cash Equivalents   $ 14,900 $ 14,900