Principles of Consolidation, Organization and Nature of Operations (Detail Textuals) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Feb. 09, 2017
Feb. 06, 2017
Dec. 13, 2016
Sep. 14, 2016
Apr. 01, 2016
Sep. 30, 2016
Dec. 31, 2016
Dec. 31, 2015
Feb. 16, 2017
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Increase in net cash used in operating activities             $ (12,294) $ (12,958)  
Reduction in vendor accounts payable             (3,217) $ (4,721)  
Proceeds from convertible notes             8,929    
Series H Warrant                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceed from warrant exercise       $ 2,200   $ 1,600      
Series I Warrant                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceed from warrant exercise     $ 3,600            
Subsequent events | Series K Warrant                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceeds from issuance of common stock   $ 11,500              
Shares issued upon exercise of warrants   3,710,000              
Proceed from warrant exercise   $ 10,600              
Subsequent events | Series M Warrant                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Shares issued upon exercise of warrants 1,800,000                
Proceed from warrant exercise $ 5,500                
Subsequent events | Series N Warrant                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Shares issued upon exercise of warrants                 750,000
Subsequent events | Series L Warrants                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Shares issued upon exercise of warrants   1,613,080              
Convertible Preferred Stock                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceed from warrant exercise             1,570    
Amount received in cash from issuance of preferred stock and warrants       $ 2,800          
Preferred stock, dividend rate, percentage       12.50%          
Class A common stock                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceeds from issuance of common stock     $ 4,100            
Shares issued upon exercise of warrants     616,667 16,970   9,515      
Class A common stock | Series H Warrant                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Shares issued upon exercise of warrants       6.0606          
Class A common stock | Subsequent events                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceeds from issuance of common stock $ 6,000                
Shares issued upon exercise of warrants 1,800,000 3,710,000              
2016 Note Offering                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Shares issued upon exercise of warrants         9,710        
Net proceed received from unrestricted cash             $ 8,900    
Senior Secured Convertible Notes                  
Principles Of Consolidation, Organization And Nature Of Operations [Line Items]                  
Proceed from warrant exercise         $ 9,100        
Amount received in cash from issuance of preferred stock and warrants         $ 10,000