Quarterly report pursuant to Section 13 or 15(d)

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

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Fair Value Measurements - National Financial Instruments Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Assets        
Long-term investments, at fair value $ 565   $ 1,390  
Total 565   1,390  
Liabilities        
Liabilities 10,573   14,846  
Convertible Debt [Member]        
Liabilities        
Liabilities   $ 6    
National Holdings Corporation [Member]        
Assets        
Total   3,812   $ 1,985
Liabilities        
Liabilities   897   6,059
Warrant [Member]        
Liabilities        
Liabilities 0   87  
Warrant [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,551   548
Helocyte Convertible Note One [Member]        
Liabilities        
Liabilities 333   4,700  
Corporate stock Assets [Member]        
Liabilities        
Liabilities   2    
Corporate stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   32   116
Municipal bonds Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,183   1,239
Restricted stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,046   82
Municipal bonds Liabilities [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       151
Contingent Consideration [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities   889   311
Warrants Issuable [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       5,597
Caelum Convertible Notes [Member]        
Liabilities        
Liabilities 10,240   10,059  
Fair Value, Inputs, Level 1 [Member]        
Assets        
Long-term investments, at fair value 0   0  
Total 0   0  
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 1 [Member] | Convertible Debt [Member]        
Liabilities        
Liabilities   0    
Fair Value, Inputs, Level 1 [Member] | National Holdings Corporation [Member]        
Assets        
Total   32   116
Liabilities        
Liabilities   2   0
Fair Value, Inputs, Level 1 [Member] | Warrant [Member]        
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 1 [Member] | Warrant [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 1 [Member] | Helocyte Convertible Note One [Member]        
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 1 [Member] | Corporate stock Assets [Member]        
Liabilities        
Liabilities   2    
Fair Value, Inputs, Level 1 [Member] | Corporate stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   32   116
Fair Value, Inputs, Level 1 [Member] | Municipal bonds Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 1 [Member] | Restricted stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 1 [Member] | Municipal bonds Liabilities [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       0
Fair Value, Inputs, Level 1 [Member] | Contingent Consideration [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities   0   0
Fair Value, Inputs, Level 1 [Member] | Warrants Issuable [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       0
Fair Value, Inputs, Level 1 [Member] | Caelum Convertible Notes [Member]        
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 2 [Member]        
Assets        
Long-term investments, at fair value 0   0  
Total 0   0  
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 2 [Member] | Convertible Debt [Member]        
Liabilities        
Liabilities   6    
Fair Value, Inputs, Level 2 [Member] | National Holdings Corporation [Member]        
Assets        
Total   2,229   1,321
Liabilities        
Liabilities   6   151
Fair Value, Inputs, Level 2 [Member] | Warrant [Member]        
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 2 [Member] | Warrant [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 2 [Member] | Helocyte Convertible Note One [Member]        
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 2 [Member] | Corporate stock Assets [Member]        
Liabilities        
Liabilities   0    
Fair Value, Inputs, Level 2 [Member] | Corporate stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 2 [Member] | Municipal bonds Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,183   1,239
Fair Value, Inputs, Level 2 [Member] | Restricted stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,046   82
Fair Value, Inputs, Level 2 [Member] | Municipal bonds Liabilities [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       151
Fair Value, Inputs, Level 2 [Member] | Contingent Consideration [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities   0   0
Fair Value, Inputs, Level 2 [Member] | Warrants Issuable [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       0
Fair Value, Inputs, Level 2 [Member] | Caelum Convertible Notes [Member]        
Liabilities        
Liabilities 0   0  
Fair Value, Inputs, Level 3 [Member]        
Assets        
Long-term investments, at fair value 565   1,390  
Total 565   1,390  
Liabilities        
Liabilities 10,573   14,846  
Fair Value, Inputs, Level 3 [Member] | Convertible Debt [Member]        
Liabilities        
Liabilities   0    
Fair Value, Inputs, Level 3 [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,551   548
Liabilities        
Liabilities   889   5,908
Fair Value, Inputs, Level 3 [Member] | Warrant [Member]        
Liabilities        
Liabilities 0   87  
Fair Value, Inputs, Level 3 [Member] | Warrant [Member] | National Holdings Corporation [Member]        
Assets        
Total   1,551   548
Fair Value, Inputs, Level 3 [Member] | Helocyte Convertible Note One [Member]        
Liabilities        
Liabilities 333   4,700  
Fair Value, Inputs, Level 3 [Member] | Corporate stock Assets [Member]        
Liabilities        
Liabilities   0    
Fair Value, Inputs, Level 3 [Member] | Corporate stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 3 [Member] | Municipal bonds Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 3 [Member] | Restricted stock Assets [Member] | National Holdings Corporation [Member]        
Assets        
Total   0   0
Fair Value, Inputs, Level 3 [Member] | Municipal bonds Liabilities [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       0
Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities   $ 889   311
Fair Value, Inputs, Level 3 [Member] | Warrants Issuable [Member] | National Holdings Corporation [Member]        
Liabilities        
Liabilities       $ 5,597
Fair Value, Inputs, Level 3 [Member] | Caelum Convertible Notes [Member]        
Liabilities        
Liabilities $ 10,240   $ 10,059