Cash and Investments in Marketable Securities - Portfolio of Cash and Investments in Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross Unrealized Losses		$ (700)
Cash	$ 11,922	1,250
Total cash and investments in marketable securities	704,388	798,783
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	640,803
Gross Unrealized Gains	4
Gross Unrealized Losses	(2,758)
Fair Value	638,049	762,625
Corporate notes and bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	196,643
Gross Unrealized Gains	4
Gross Unrealized Losses	(1,270)
Fair Value	195,377	278,121
Corporate commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	439,280
Gross Unrealized Gains	0
Gross Unrealized Losses	(1,479)
Fair Value	437,801	478,629
Obligations of U.S. government agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	4,880
Gross Unrealized Gains	0
Gross Unrealized Losses	(9)
Fair Value	4,871	5,875
Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	43,523	23,968
Certificates of deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 10,894	$ 10,940