Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v3.19.1
Income Taxes - Additional Information (Detail) - USD ($)
 1 Months Ended 12 Months Ended
Feb. 11, 2019
Nov. 14, 2018
Jul. 03, 2018
Mar. 31, 2018
Oct. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2020
Income Tax Disclosure [Line Items]                
Deferred Tax Assets, Valuation Allowance           $ 132,114,000 $ 101,645,000  
Operating Loss Carryforwards, Valuation Allowance           $ 130,100,000    
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent           21.00% 35.00%  
Deferred Income Tax Expense (Benefit)           $ 0    
Income Tax Credits and Adjustments           $ 10,200,000    
Stock Issued During Period, Shares, New Issues     164,473 5,290,000 43,292 1,841,774    
Common Stock, Shares, Issued           57,845,447 50,991,285  
Proceeds from Issuance of Common Stock $ 13,100,000         $ 10,000,000    
Sale of Stock, Number of Shares Issued in Transaction 4,000,000              
Scenario, Forecast [Member]                
Income Tax Disclosure [Line Items]                
Deferred Tax Assets, Valuation Allowance               $ 308,000,000
National Holdings Corporation [Member]                
Income Tax Disclosure [Line Items]                
Operating Loss Carryforwards, Valuation Allowance           $ 348,000,000    
Common Stock [Member]                
Income Tax Disclosure [Line Items]                
Common Stock, Shares, Issued   3,000,000            
Proceeds from Issuance of Common Stock   $ 9,800,000            
Common Stock [Member] | NHLD [Member]                
Income Tax Disclosure [Line Items]                
Business Acquisition, Percentage of Voting Interests Acquired   56.10%            
Common Stock [Member] | B.Riley financial inc.[member]                
Income Tax Disclosure [Line Items]                
Stock Issued During Period, Shares, New Issues   7,000,000            
Tax Cuts And Jobs Act [Member]                
Income Tax Disclosure [Line Items]                
Deferred Tax Assets, Valuation Allowance             $ 42,200,000