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Summary of Significant Accounting Policies - Schedule of Weighted-Average Assumptions (Details)
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected dividend yield     0.00%  
Stock options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected common stock price volatility 89.00% 84.00% 88.00% 83.00%
Risk-free interest rate, minimum 1.38% 2.80% 1.38% 2.39%
Risk-free interest rate, maximum 1.84% 2.90% 2.54% 2.90%
Expected term of options (years) 6 years 1 month 6 days 6 years 1 month 6 days 5 years 8 months 12 days 5 years 9 months 18 days
Expected dividend yield 0.00% 0.00% 0.00% 0.00%