Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Financial Instruments Measured at Fair Value on Recurring Basis (Detail)

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Fair Value Measurements - Financial Instruments Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Sep. 30, 2016
Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value $ 2,178 $ 0
Long-term investments, at fair value 685 2,485
Helocyte convertible note, at fair value 3,031 0
Total liabilities 3,982  
Restricted Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 514  
Corporate Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 114  
Municipal Bonds [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 1,550  
Warrant [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 98 114
Warrant [Member] | Contingently Issuable Warrants [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 853  
Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 1,664  
Long-term investments, at fair value 0 0
Helocyte convertible note, at fair value 0  
Total liabilities 0  
Fair Value, Inputs, Level 1 [Member] | Restricted Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 0  
Fair Value, Inputs, Level 1 [Member] | Corporate Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 114  
Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 1,550  
Fair Value, Inputs, Level 1 [Member] | Warrant [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 0 0
Fair Value, Inputs, Level 1 [Member] | Warrant [Member] | Contingently Issuable Warrants [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 0  
Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 514  
Long-term investments, at fair value 0 0
Helocyte convertible note, at fair value 0  
Total liabilities 0  
Fair Value, Inputs, Level 2 [Member] | Restricted Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 514  
Fair Value, Inputs, Level 2 [Member] | Corporate Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 0  
Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 0  
Fair Value, Inputs, Level 2 [Member] | Warrant [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 0 0
Fair Value, Inputs, Level 2 [Member] | Warrant [Member] | Contingently Issuable Warrants [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 0  
Fair Value, Inputs, Level 3 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 685  
Long-term investments, at fair value 685 2,485
Helocyte convertible note, at fair value 3,031  
Total liabilities 3,982  
Fair Value, Inputs, Level 3 [Member] | Restricted Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 0  
Fair Value, Inputs, Level 3 [Member] | Corporate Stock [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 0  
Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member] | National Holdings Corporation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment Owned, at Fair Value 0  
Fair Value, Inputs, Level 3 [Member] | Warrant [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities 98 $ 114
Fair Value, Inputs, Level 3 [Member] | Warrant [Member] | Contingently Issuable Warrants [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liabilities $ 853