Investments - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Fair Value	$ 446,243	$ 427,288
Fair Value Measurements on Recurring Basis
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	452,890	429,071
Short-term investments, Unrealized Gains	2
Short-term investments, Unrealized Losses	(6,649)	(1,783)
Short-term investments, Fair Value	446,243	427,288
Cash equivalents and Short-term investments, Amortized Cost	482,135	508,966
Cash equivalents and Short-term investments, Unrealized Gains	2
Cash equivalents and Short-term investments, Unrealized Losses	(6,649)	(1,783)
Cash equivalents and Short-term investments, Estimated Fair Value	$ 475,488	$ 507,183
Fair Value Measurements on Recurring Basis \| Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less	1 or less
Cash equivalents, Amortized Cost	$ 29,245	$ 79,895
Cash equivalents, Fair Value	29,245	79,895
Fair Value Measurements on Recurring Basis \| Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	192,065	208,064
Short-term investments, Unrealized Losses	(3,366)	(892)
Short-term investments, Fair Value	$ 188,699	$ 207,172
Fair Value Measurements on Recurring Basis \| Corporate Debt Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	3 years	3 years
Fair Value Measurements on Recurring Basis \| U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 170,309	$ 135,452
Short-term investments, Unrealized Gains	2
Short-term investments, Unrealized Losses	(2,372)	(619)
Short-term investments, Fair Value	$ 167,939	$ 134,833
Fair Value Measurements on Recurring Basis \| U.S. Treasury Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	3 years	3 years
Fair Value Measurements on Recurring Basis \| Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 58,427	$ 53,439
Short-term investments, Fair Value	$ 58,427	$ 53,439
Fair Value Measurements on Recurring Basis \| Commercial Paper \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 year	1 year
Fair Value Measurements on Recurring Basis \| Non U S Government And Supranational Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 23,094	$ 23,122
Short-term investments, Unrealized Losses	(719)	(214)
Short-term investments, Fair Value	$ 22,375	$ 22,908
Fair Value Measurements on Recurring Basis \| Non U S Government And Supranational Debt Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	3 years	3 years
Fair Value Measurements on Recurring Basis \| U.S. Agency Bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 8,995	$ 8,994
Short-term investments, Unrealized Losses	(192)	(58)
Short-term investments, Fair Value	$ 8,803	$ 8,936
Fair Value Measurements on Recurring Basis \| U.S. Agency Bonds \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	2 years	2 years

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