Quarterly report pursuant to Section 13 or 15(d)

Capitalization and Equity Structure - Warrants (Details)

v3.19.2
Capitalization and Equity Structure - Warrants (Details) - $ / shares
shares in Thousands
 1 Months Ended 6 Months Ended
Dec. 31, 2015
Jun. 30, 2019
May 31, 2019
May 22, 2019
Sep. 30, 2017
Schedule of Capitalization, Equity [Line Items]          
Exercise price (in dollars per share)       $ 2  
Class Of Warrant Or Right, Outstanding [Roll Forward]          
Beginning balance (in shares)   3,396      
Issued (in shares)   6,667      
Expired (in shares)   1,504      
Ending balance (in shares)   8,559      
2019 Warrants          
Schedule of Capitalization, Equity [Line Items]          
Exercise price (in dollars per share)   $ 2 $ 2    
Term (Years)   5 years      
Class Of Warrant Or Right, Outstanding [Roll Forward]          
Beginning balance (in shares)   0      
Issued (in shares)   6,667      
Expired (in shares)   0      
Ending balance (in shares)   6,667      
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      
Issued (in shares)   0      
Expired (in shares)   0      
Ending balance (in shares)   200      
2015 Warrants          
Schedule of Capitalization, Equity [Line Items]          
Exercise price (in dollars per share) $ 3.74 $ 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 0      
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      
Issued (in shares)   0      
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      
Issued (in shares)   0      
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      
Issued (in shares)   0      
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