Consolidated Statements of Stockholders' Equity (Deficit) - USD ($)
$ in Thousands
Total
Common Stock [Member]
Additional Paid-In Capital [Member]
Treasury Stock [Member]
Accumulated Deficit [Member]
Series A Preferred Stock [Member]
Beginning Balance at Dec. 31, 2012 $ 49,778 $ 38 $ 143,703 $ (47) $ (93,919) $ 3
Beginning Balance, shares at Dec. 31, 2012   37,497,703       2,709,300
Stock-based compensation 3,327   3,327      
Stock option exercise $ 357   357      
Stock option exercise, shares 115,667 115,667        
Restricted stock awards, shares   80,498        
Warrant derivative liability reclassified to equity $ 11   11      
Warrant exercises 50   50      
Warrant exercises, shares   10,000        
Shares issued to Arcion in acquisition of research and development license 2,073 $ 1 2,072      
Shares issued to Arcion in acquisition of research and development license, shares   500,516        
Warrants issued in connection with notes payable 986   986      
Net loss (57,394)       (57,394)  
Ending Balance at Dec. 31, 2013 (812) $ 39 150,506 (47) (151,313) $ 3
Ending Balance, shares at Dec. 31, 2013   38,204,384       2,709,300
Stock-based compensation 6,883   6,883      
Stock option exercise $ 4,580 $ 1 4,579      
Stock option exercise, shares 1,332,563 1,332,563        
Restricted stock awards, shares   473,893        
Warrant derivative liability reclassified to equity $ 17,478   17,478      
Warrant exercises 7,741 $ 2 7,739      
Warrant exercises, shares   1,999,153        
Cashless exercise of warrants 0 $ 0 0 0 0 $ 0
Cashless exercise of warrants, shares   218,367        
Shares issued pursuant to registered direct offering, net 58,182 $ 8 58,174      
Shares issued pursuant to registered direct offering, net shares   7,500,000        
Shares issued pursuant to an at the market offering, net 14,480 $ 1 14,479      
Shares issued pursuant to an at the market offering, shares   1,304,410        
Short swing profit return 82   82      
Conversion of preferred shares to common shares   $ 1       $ (1)
Conversion of preferred shares to common shares, shares   570,300       (570,300)
Net loss (54,218)       (54,218)  
Ending Balance at Dec. 31, 2014 54,396 $ 52 259,920 $ (47) $ (205,531) $ 2
Ending Balance, shares at Dec. 31, 2014   51,603,070       2,139,000
Stock-based compensation $ 14,249   $ 14,249      
Stock-based compensation, shares 0 0 0 0 0 0
Stock option exercise $ 755   $ 755      
Stock option exercise, shares 235,480 223,923        
Restricted stock awards $ 1 $ 1        
Restricted stock awards, shares   857,677        
Warrant exercises 1   1      
Warrant exercises, shares   284        
Short swing profit return 6   6      
Conversion of preferred shares to common shares, shares   45,845       (45,845)
Equity financing costs (40)   (40)      
Net loss (37,672)       $ (37,672)  
Ending Balance at Dec. 31, 2015 $ 31,696 $ 53 $ 274,891 $ (47) $ (243,203) $ 2
Ending Balance, shares at Dec. 31, 2015   52,730,799       2,093,155