Summary of Significant Accounting Policies - Redeemable Convertible Preferred Stock Assumptions (Details) - Redeemable convertible preferred stock outstanding	9 Months Ended
	Sep. 30, 2020
Subsidiary, Sale of Stock [Line Items]
Warrant term (in years)	1 year 4 months 24 days
Expected volatility
Subsidiary, Sale of Stock [Line Items]
Measurement input (percent)	0.80
Risk-free interest rate
Subsidiary, Sale of Stock [Line Items]
Measurement input (percent)	0.001
Dividend yield
Subsidiary, Sale of Stock [Line Items]
Measurement input (percent)	0