Convertible Preferred Stock - Schedule of Initial Conversion Price Per Share for each Series of Convertible Preferred Stock (Detail)	Sep. 30, 2020 $ / shares
Redeemable Convertible Series A Preferred Stock [Member]
Disclosure Of Conversion Price Of Temporary Equity Into Permanent Equity [Line Items]
Temporary Equity Initial Conversion Price Per Share	$ 8.295
Redeemable Convertible Series B Preferred Stock [Member]
Disclosure Of Conversion Price Of Temporary Equity Into Permanent Equity [Line Items]
Temporary Equity Initial Conversion Price Per Share	13.370
Redeemable Convertible Series C Preferred Stock [Member]
Disclosure Of Conversion Price Of Temporary Equity Into Permanent Equity [Line Items]
Temporary Equity Initial Conversion Price Per Share	16.667
Redeemable Convertible Series D Preferred Stock [Member]
Disclosure Of Conversion Price Of Temporary Equity Into Permanent Equity [Line Items]
Temporary Equity Initial Conversion Price Per Share	$ 16.667