Quarterly report pursuant to Section 13 or 15(d)

Capitalization and Equity Structure - Warrants (Details)

v3.19.1
Capitalization and Equity Structure - Warrants (Details) - $ / shares
shares in Thousands
 1 Months Ended 3 Months Ended
Dec. 31, 2015
Mar. 31, 2019
Sep. 30, 2017
Class Of Warrant Or Right, Outstanding [Roll Forward]      
Beginning balance (in shares)   3,396  
Expired (in shares)   1,504  
Ending balance (in shares)   1,892  
Information Agent Warrants      
Schedule of Capitalization, Equity [Line Items]      
Exercise price (in dollars per share)   $ 1.5 $ 1.5
Term (Years)   3 years  
Class Of Warrant Or Right, Outstanding [Roll Forward]      
Beginning balance (in shares)   200  
Expired (in shares)   0  
Ending balance (in shares)   200  
2015 Warrants      
Schedule of Capitalization, Equity [Line Items]      
Exercise price (in dollars per share)   $ 2.75  
Term (Years)   5 years  
Class Of Warrant Or Right, Outstanding [Roll Forward]      
Beginning balance (in shares)   1,604  
Issued (in shares) 2,122    
Expired (in shares)   0  
Ending balance (in shares)   1,604  
Placement agent warrants      
Schedule of Capitalization, Equity [Line Items]      
Exercise price (in dollars per share)   $ 7  
Term (Years)   5 years  
Class Of Warrant Or Right, Outstanding [Roll Forward]      
Beginning balance (in shares)   426  
Expired (in shares)   426  
Ending balance (in shares)   0  
PPO warrants      
Schedule of Capitalization, Equity [Line Items]      
Exercise price (in dollars per share)   $ 14  
Term (Years)   5 years  
Class Of Warrant Or Right, Outstanding [Roll Forward]      
Beginning balance (in shares)   1,078  
Expired (in shares)   1,078  
Ending balance (in shares)   0  
Pre-2014 warrants      
Schedule of Capitalization, Equity [Line Items]      
Exercise price (in dollars per share)   $ 9.66  
Class Of Warrant Or Right, Outstanding [Roll Forward]      
Beginning balance (in shares)   88  
Expired (in shares)   0  
Ending balance (in shares)   88  
Pre-2014 warrants | Minimum      
Schedule of Capitalization, Equity [Line Items]      
Term (Years)   9 years  
Pre-2014 warrants | Maximum      
Schedule of Capitalization, Equity [Line Items]      
Term (Years)   10 years