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Equity Incentive Plans - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | ---
Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Jun. 30, 2021 | Sep. 30, 2021 | Sep. 30, 2020 | Jul. 31, 2021 | Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Weighted-average grant-date fair values of options granted |  |  |  |  |  |  |  | $ 10.56 | $ 2.31 |  |
Aggregate intrinsic value of options exercised |  |  |  |  |  |  |  | $ 4,200,000 |  |  |
Unrecognized stock-based compensation of unvested options | $ 25,100,000 |  |  |  |  |  |  | $ 25,100,000 |  |  |
Weighted-average period expected to recognize |  |  |  |  |  |  |  | 3 years 6 months |  |  |
Dividend yield |  |  |  |  |  |  | 0.00% |  |  |  |
Common stock reserved for future issuance | 11,434,564 |  |  |  |  |  |  | 11,434,564 |  |  | 29,782,878
Share of common stock purchased | $ 1,899,000 | $ 931,000 | $ 277,000 | $ 165,000 | $ 65,000 | $ 61,000 |  |  |  |  |
Restricted Stock Units RSU |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  |  | 4 years |  |  |
Unrecognized stock-based compensation of unvested options | 500,000 |  |  |  |  |  |  | $ 500,000 |  |  |
Weighted-average period expected to recognize |  |  |  |  |  |  |  | 3 years 10 months 24 days |  |  |
Number of Shares, Granted |  |  |  |  |  |  |  | 23,800 |  |  |
Weighted-Average Exercise Price, Granted |  |  |  |  |  |  |  | $ 22.70 |  |  |
Maximum | Restricted Stock Units RSU |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Stock based compensation | $ 100 |  |  |  |  |  |  |  |  |  |
2011 Plan |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock available for issuance |  |  |  |  |  |  |  |  |  |  | 451,670
2021 Plan |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock available for issuance | 5,331,595 |  |  |  |  |  |  | 5,331,595 |  |  |
Common stock reserved for future issuance |  |  |  |  |  |  |  |  |  | 5,200,000 |
2021 Employee Stock Purchase Plan |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock reserved for future issuance |  |  |  |  |  |  |  |  |  | 850,000 |
Share of common stock purchased |  |  |  |  |  |  |  | $ 0 |  |  |

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