Quarterly report pursuant to Section 13 or 15(d)

Capitalization and Equity Structure - Valuation Assumptions (Details)

v3.20.2
Capitalization and Equity Structure - Valuation Assumptions (Details)
 6 Months Ended 12 Months Ended
Jun. 10, 2020
$ / shares
Jun. 30, 2020
$ / shares
Dec. 31, 2019
$ / shares
Dec. 31, 2016
$ / shares
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share)       $ 120.00
June 2020 Investor Warrants | Current share price        
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share) $ 3.81 $ 8.40    
June 2020 Investor Warrants | Conversion price        
Schedule of Capitalization, Equity [Line Items]        
Conversion price (in dollars per share) $ 5.18 $ 5.18    
June 2020 Investor Warrants | Risk-free interest rate        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage 0.0039 0.0033    
June 2020 Investor Warrants | Expected term (years)        
Schedule of Capitalization, Equity [Line Items]        
Term (years) 5 years 6 months 5 years 5 months 12 days    
June 2020 Investor Warrants | Volatility of stock        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage 0.964 1.0371    
June 2020 Placement Agent Warrants | Current share price        
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share) $ 3.81 $ 8.40    
June 2020 Placement Agent Warrants | Conversion price        
Schedule of Capitalization, Equity [Line Items]        
Conversion price (in dollars per share) $ 5.64 $ 5.64    
June 2020 Placement Agent Warrants | Risk-free interest rate        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage 0.0033 0.0029    
June 2020 Placement Agent Warrants | Expected term (years)        
Schedule of Capitalization, Equity [Line Items]        
Term (years) 5 years 4 years 11 months 12 days    
June 2020 Placement Agent Warrants | Volatility of stock        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage 0.963 1.0509    
December 2019 Warrants | Current share price        
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share)   $ 8.40 $ 5.86  
December 2019 Warrants | Conversion price        
Schedule of Capitalization, Equity [Line Items]        
Conversion price (in dollars per share)   $ 8.10 $ 8.10  
December 2019 Warrants | Risk-free interest rate        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   0.0029 0.0173  
December 2019 Warrants | Expected term (years)        
Schedule of Capitalization, Equity [Line Items]        
Term (years)   4 years 11 months 19 days 5 years 6 months  
December 2019 Warrants | Volatility of stock        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   1.049 0.957  
December 2019 Placement Agent Warrants | Current share price        
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share)   $ 8.40 $ 5.86  
December 2019 Placement Agent Warrants | Conversion price        
Schedule of Capitalization, Equity [Line Items]        
Conversion price (in dollars per share)   $ 8.44 $ 8.44  
December 2019 Placement Agent Warrants | Risk-free interest rate        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   0.0026 0.0169  
December 2019 Placement Agent Warrants | Expected term (years)        
Schedule of Capitalization, Equity [Line Items]        
Term (years)   4 years 5 months 19 days 5 years  
December 2019 Placement Agent Warrants | Volatility of stock        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   1.0817 0.931  
May 2019 Warrants | Current share price        
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share)   $ 8.40 $ 5.86  
May 2019 Warrants | Conversion price        
Schedule of Capitalization, Equity [Line Items]        
Conversion price (in dollars per share)   $ 3.52 $ 5.70  
May 2019 Warrants | Risk-free interest rate        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   0.0023 0.0167  
May 2019 Warrants | Expected term (years)        
Schedule of Capitalization, Equity [Line Items]        
Term (years)   3 years 10 months 24 days 4 years 4 months 24 days  
May 2019 Warrants | Volatility of stock        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   1.109 0.939  
2015 Warrants | Current share price        
Schedule of Capitalization, Equity [Line Items]        
Current share price (in dollars per share)   $ 8.40 $ 5.86  
2015 Warrants | Conversion price        
Schedule of Capitalization, Equity [Line Items]        
Conversion price (in dollars per share)   $ 41.25 $ 41.25  
2015 Warrants | Risk-free interest rate        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   0.0018 0.0159  
2015 Warrants | Expected term (years)        
Schedule of Capitalization, Equity [Line Items]        
Term (years)   6 months 11 months 26 days  
2015 Warrants | Volatility of stock        
Schedule of Capitalization, Equity [Line Items]        
Measurement input percentage   1.1194 0.9846