Summary of Significant Accounting Policies - Fair Value Assumptions, Warrant Liabilities (Details)	Dec. 31, 2019	Dec. 31, 2018
Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability assumptions	0.9804	1.0290
Risk-free interest rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability assumptions	0.0181	0.0263
Weighted average expected life (in years)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability assumptions	6.25	1.29
Dividend yield
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability assumptions	0	0