Fair Value Measurements - Future Tranche Rights (Details)	Dec. 31, 2019 $ / shares	Dec. 23, 2019 $ / shares
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	0.0179	0.0182
Risk-free interest rate | Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.82	1.82
Risk-free interest rate | Preferred stock | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.84	1.86
Risk-free interest rate | Preferred stock | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.88	1.89
Expected term
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	0.0698	0.0700
Expected term | Warrants | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	8.16	8.18
Expected term | Warrants | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	9.16	9.18
Expected term | Preferred stock | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.16	1.18
Expected term | Preferred stock | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	2.16	2.18
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	0.80	0.80
Expected volatility | Future tranche right liability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	80	80
Exercise price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.5200	1.5200
Exercise price | Future tranche right liability | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.52	1.52
Exercise price | Future tranche right liability | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt instrument measurement input	1.82	1.82