Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v3.8.0.1
Income Taxes - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Line Items]        
Deferred Tax Assets, Valuation Allowance   $ 101,645 $ 94,687  
Operating Loss Carryforwards, Valuation Allowance   $ 101,600,000    
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent   35.00% 35.00% 35.00%
Deferred Income Tax Expense (Benefit)   $ 0 $ (73,000) $ 0
Income Tax Credits and Adjustments   7,500,000    
Scenario, Plan [Member]        
Income Tax Disclosure [Line Items]        
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 21.00%      
National Holdings Corporation [Member]        
Income Tax Disclosure [Line Items]        
Deferred Tax Assets, Valuation Allowance     $ 8,800,000  
Operating Loss Carryforwards, Valuation Allowance   259,000,000    
Business Acquisition, Percentage of Voting Interests Acquired     56.00%  
State and Local Jurisdiction [Member]        
Income Tax Disclosure [Line Items]        
Deferred Tax Assets, Valuation Allowance   $ 7,000,000