Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of cost to be recognized for option under share-based payment arrangement.

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Stockholders' Equity - Stock Options - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses	$ 13,300,000		$ 13,300,000
Unrecognized compensation expense, weighted-average period			1 year 8 months 8 days
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses	284,000		$ 284,000
Unrecognized compensation expense, weighted-average period			4 months 17 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	7,700,000	$ 5,400,000	$ 15,800,000	$ 10,000,000.0
Unrecognized compensation expenses	$ 48,600,000		$ 48,600,000
Unrecognized compensation expense, weighted-average period			2 years 5 months 15 days