Common Stock - Summary of Shares of Common Stock Reserved for Future Issuance (Detail) - shares	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock reserved for future issuance	11,815,000	9,526,000	7,291,000
2017 Stock Incentive Plan [Member]
Class Of Stock [Line Items]
Common stock reserved for future issuance	11,013,982	8,613,000	6,319,000
2017 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Common stock reserved for future issuance	801,000	913,000	972,000