Convertible Notes - Additional Information (Details) - USD ($)		1 Months Ended	9 Months Ended		12 Months Ended
	Nov. 30, 2019	Apr. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes			$ 0	$ 19,451,000
Convertible Notes | Series C Convertible Preferred Stock
Debt Instrument [Line Items]
Conversion of convertible notes payable to preferred stock	6,893,036
2018 Notes
Debt Instrument [Line Items]
Face amount of loans						$ 3,000,000
Convertible promissory notes accrued interest rate						8.00%
Convertible promissory notes conversion percentage on per share price paid by investors						85.00%
Qualified financing of convertible promissory notes converted into preferred equity						$ 10,000,000
2019 Notes
Debt Instrument [Line Items]
Face amount of loans					$ 4,500,000
Convertible promissory notes accrued interest rate					10.00%
Convertible promissory notes conversion percentage on per share price paid by investors					80.00%
Qualified financing of convertible promissory notes converted into preferred equity					$ 10,000,000
Lilly Note
Debt Instrument [Line Items]
Convertible promissory notes accrued interest rate		8.00%
Proceeds from issuance of convertible notes		$ 15,000,000
Maturity date		2020-10
Lilly Note | Series C Convertible Preferred Stock
Debt Instrument [Line Items]
Conversion of convertible notes payable to preferred stock	4,576,342