Quarterly report pursuant to Section 13 or 15(d)

Warrants - Summary of Warrant Activity (Details)

v3.19.3
Warrants - Summary of Warrant Activity (Details) - $ / shares
shares in Thousands
9 Months Ended
Sep. 30, 2019
Jan. 14, 2019
Jan. 09, 2019
Dec. 31, 2018
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 104.18 $ 7.43 $ 7.43  
Warrants outstanding (in shares) 336      
Warrants issued (in shares) 66      
Warrants expired (in shares) (123)      
Warrants outstanding (in shares) 279      
Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 115.54      
Warrants outstanding (in shares) 147      
Warrants issued (in shares) 66      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 213      
Warrant Issued For | Derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 67.50      
Warrants outstanding (in shares) 189      
Warrants issued (in shares) 0      
Warrants expired (in shares) (123)      
Warrants outstanding (in shares) 66      
Financing | Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 300.00      
Warrants outstanding (in shares) 8      
Warrants issued (in shares) 0      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 8      
Financing | Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 450.00      
Warrants outstanding (in shares) 9      
Warrants issued (in shares) 0      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 9      
2017 Debt | Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 27.60      
Warrants outstanding (in shares) 15      
Warrants issued (in shares) 0      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 15      
2015 Offering | Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 150.00      
Warrants outstanding (in shares) 115      
Warrants issued (in shares) 0      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 115      
2019 Offering | Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 7.43      
Warrants outstanding (in shares) 0      
Warrants issued (in shares) 31      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 31      
2019 Offering | Warrant Issued With | Non-derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 7.59      
Warrants outstanding (in shares) 0      
Warrants issued (in shares) 35      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 35      
2016 Offerings        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 67.50     $ 67.50
2016 Offerings | Warrant Issued For | Derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 67.50      
Warrants outstanding (in shares) 66      
Warrants issued (in shares) 0      
Warrants expired (in shares) 0      
Warrants outstanding (in shares) 66      
2017 Offering | Warrant Issued For | Derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 70.50      
Warrants outstanding (in shares) 117      
Warrants issued (in shares) 0      
Warrants expired (in shares) (117)      
Warrants outstanding (in shares) 0      
2017 Offering | Warrant Issued For | Derivative warrants        
Class of Warrant or Right [Line Items]        
Warrants, exercise price (usd per share) $ 75.00      
Warrants outstanding (in shares) 6      
Warrants issued (in shares) 0      
Warrants expired (in shares) (6)      
Warrants outstanding (in shares) 0