Convertible Preferred Stock and Stockholders' Deficit - Summary of Shares of Common Stock Reserved for Future Issuance (Detail)	Sep. 30, 2021 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance net	15,201,904
Options Outstanding [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance net	5,440,173
2010 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance net	4,094,753
Redeemable Convertible Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance net	2,457,143
Non-Redeemable Convertible Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock reserved for future issuance net	3,209,835