Incentive Stock Options and Employee Stock Purchase Plan - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions			6 Months Ended
	Jan. 01, 2020	Jun. 15, 2018	Jun. 30, 2021	Jun. 30, 2020	Jan. 20, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to unvested stock-based awards			$ 57.4
Unrecognized compensation cost, period for recognition			2 years 10 months 24 days
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of stock options, exercised			$ 3.8	$ 10.7
Weighted average grant-date fair value			$ 13.56	$ 5.50
2021 Inducement Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant					2,612,550
2018 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved for issuance			10,471,204			7,457,171
Increase in common stock issued	3,001,185
Percentage of exercise price per share of fair market value		100.00%
Expiration period of stock options after grant date		10 years
2018 Stock Incentive Plan [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options for purchase of common stock held, exercisable period		1 year
2018 Stock Incentive Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options for purchase of common stock held, exercisable period		4 years
2018 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved for issuance			870,096
Number of stock issued during period under the plan			54,152
2016 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sharebased Compensation Arrangement by Sharebased Payment Award Shares Cancelled in Period			12,848

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