Quarterly report pursuant to Section 13 or 15(d)

Capitalization and Equity Structure - Valuation Assumptions (Details)

v3.19.2
Capitalization and Equity Structure - Valuation Assumptions (Details)
 6 Months Ended
May 24, 2019
$ / shares
Jun. 30, 2019
$ / shares
Dec. 31, 2016
$ / shares
Schedule of Capitalization, Equity [Line Items]      
Current share price (in dollars per share)     $ 8.00
2019 Warrants | Current share price      
Schedule of Capitalization, Equity [Line Items]      
Current share price (in dollars per share) $ 1.49 $ 1.27  
2019 Warrants | Conversion price      
Schedule of Capitalization, Equity [Line Items]      
Conversion price (in dollars per share) $ 2.00 $ 2.00  
2019 Warrants | Risk-free interest rate      
Schedule of Capitalization, Equity [Line Items]      
Measurement input percentage 0.0212 0.0176  
2019 Warrants | Term (years)      
Schedule of Capitalization, Equity [Line Items]      
Term (years) 5 years 4 years 10 months 24 days  
2019 Warrants | Volatility of stock      
Schedule of Capitalization, Equity [Line Items]      
Measurement input percentage 0.980 0.967  
2015 Warrants | Current share price      
Schedule of Capitalization, Equity [Line Items]      
Current share price (in dollars per share)   $ 1.27  
2015 Warrants | Conversion price      
Schedule of Capitalization, Equity [Line Items]      
Conversion price (in dollars per share)   $ 2.75  
2015 Warrants | Risk-free interest rate      
Schedule of Capitalization, Equity [Line Items]      
Measurement input percentage   1.84  
2015 Warrants | Term (years)      
Schedule of Capitalization, Equity [Line Items]      
Term (years)   1 year 6 months  
2015 Warrants | Volatility of stock      
Schedule of Capitalization, Equity [Line Items]      
Measurement input percentage   102.0