Quarterly report pursuant to Section 13 or 15(d)

Common Stock Warrants - Summary of Common Stock Warrants Outstanding (Details)

v3.19.2
Common Stock Warrants - Summary of Common Stock Warrants Outstanding (Details) - $ / shares
6 Months Ended
Jun. 30, 2019
Dec. 31, 2018
Class Of Warrant Or Right [Line Items]    
Warrant outstanding (in shares) 28,489 23,644
Five Year Warrants Issued in February 2015 [Member] | Stockholders' Equity [Member]    
Class Of Warrant Or Right [Line Items]    
Issuance Date 2015-02  
Expiration Date 2020-02  
Exercise price of warrants (in dollars per share) $ 66.20  
Warrant outstanding (in shares) 9,063 9,063
Five Year Warrants Issued in February 2016 [Member] | Stockholders' Equity [Member]    
Class Of Warrant Or Right [Line Items]    
Issuance Date 2016-02  
Expiration Date 2021-02  
Exercise price of warrants (in dollars per share) $ 15.40  
Warrant outstanding (in shares) 8,249 8,249
Five Year Warrants Issued in May 2018 [Member] | Stockholders' Equity [Member]    
Class Of Warrant Or Right [Line Items]    
Issuance Date 2018-05  
Expiration Date 2028-05  
Exercise price of warrants (in dollars per share) $ 23.69  
Warrant outstanding (in shares) 6,332 6,332
Five Year Warrants Issued in March 2019 [Member] | Stockholders' Equity [Member]    
Class Of Warrant Or Right [Line Items]    
Issuance Date 2019-03  
Expiration Date 2029-03  
Exercise price of warrants (in dollars per share) $ 14.71  
Warrant outstanding (in shares) 4,845