Fair Value Measurements - Future Tranche Rights (Details)	Dec. 31, 2020 $ / shares USD ($)	Dec. 31, 2019 $ / shares
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	0.0050	0.0179
Risk-free interest rate | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	0.64
Risk-free interest rate | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	0.73
Risk-free interest rate | Preferred stock | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input		1.84
Risk-free interest rate | Preferred stock | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input		1.88
Expected term
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	0.0598	0.0698
Expected term | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	0.25
Expected term | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	1.12
Expected term | Warrants | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	7.25	8.16
Expected term | Warrants | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	8.12	9.16
Expected term | Preferred stock | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input		1.16
Expected term | Preferred stock | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input		2.16
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	0.80	0.80
Expected volatility | Future tranche right liability
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	80	80
Exercise price
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input | $ / shares	1.52	1.52
Exercise price | Future tranche right liability | Minimum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	1.52	1.52
Exercise price | Future tranche right liability | Maximum
Fair Value Measurement Inputs and Valuation Techniques
Debt instrument measurement input	1.82	1.82