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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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Aggregate number of common shares reserved for future issuance.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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