Quarterly report pursuant to Section 13 or 15(d)

Related Party Transactions - Additional Information (Detail)

v3.8.0.1
Related Party Transactions - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended
May 31, 2015
Mar. 31, 2018
Mar. 31, 2017
Feb. 02, 2018
Related Party Transaction [Line Items]        
Lease Sharing Agreements Contributions To Property Under Lease   $ 32,000    
Description Of Fee Paid   NSC received a fee of approximately $1.8 million, or 8% on the gross proceeds raised of $23.0 million. The fees were eliminated in consolidation.    
Proceeds from Other Debt   $ 21,707,000 $ 0  
Noninterest Expense Transfer Agent and Custodian Fees   $ 1,700,000    
National Holdings Corporation [Member]        
Related Party Transaction [Line Items]        
Business Acquisition, Percentage of Voting Interests Acquired   56.60%    
Opus Credit Facility [Member]        
Related Party Transaction [Line Items]        
Payments of Loan Costs   $ 300,000 200,000  
Debt Instrument, Interest Rate, Stated Percentage   12.00%    
Chief Executive Officer [Member]        
Related Party Transaction [Line Items]        
Interest own in percent by principal stockholder or director   13.70%    
Chord Advisors, LLC [Member]        
Related Party Transaction [Line Items]        
Related Party Transaction, Expenses from Transactions with Related Party $ 10,000      
Board of Directors Chairman [Member] | National Holdings Corporation [Member]        
Related Party Transaction [Line Items]        
Equity Method Investment, Ownership Percentage   4.60%    
TG Therapeutics, Inc [Member]        
Related Party Transaction [Line Items]        
Due from Related Parties, Current   $ 14,000    
Checkpoint [Member] | Chord Advisors, LLC [Member]        
Related Party Transaction [Line Items]        
Related Party Transaction, Expenses from Transactions with Related Party   $ 11,000 13,000  
Founders Agreement [Member] | Avenue Therapeutics, Inc. [Member]        
Related Party Transaction [Line Items]        
Other Fee,Percentage   2.50%    
OPPM [Member]        
Related Party Transaction [Line Items]        
Payments for Rent   $ 42,000    
Due from Related Parties, Current   $ 3,000    
Executives Vice Chairman [Member]        
Related Party Transaction [Line Items]        
Interest own in percent by principal stockholder or director   16.00%    
Collaborative Agreements with TGTX [Member]        
Related Party Transaction [Line Items]        
Proceeds from Option Fee       $ 50,000
Avenue [Member] | Chord Advisors, LLC [Member]        
Related Party Transaction [Line Items]        
Related Party Transaction, Expenses from Transactions with Related Party $ 5,000      
Desk Share Agreements [Member]        
Related Party Transaction [Line Items]        
Payments for Rent   $ 600,000    
Desk Share Agreements [Member] | TG Therapeutics, Inc [Member]        
Related Party Transaction [Line Items]        
Due from Related Parties, Current   137,000    
Desk Share Agreements [Member] | OPPM [Member]        
Related Party Transaction [Line Items]        
Due from Related Parties, Current   61,000    
Shared Services Agreement [Member] | TG Therapeutics, Inc [Member]        
Related Party Transaction [Line Items]        
Proceeds from Related Party Agreement   300,000 $ 200,000  
Due from Related Parties   $ 300,000