Cash and Investments in Marketable Securities - Portfolio of Cash and Investments in Marketable Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross Unrealized Losses		$ (700)
Cash	$ 8,341	1,250
Total cash and investments in marketable securities	546,387	798,783
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	474,848
Gross Unrealized Gains	0
Gross Unrealized Losses	(3,252)
Fair Value	471,596	762,625
Level 2 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	115,652
Gross Unrealized Gains	0
Gross Unrealized Losses	(1,489)
Fair Value	114,163	278,121
Level 2 | Corporate commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	358,066
Gross Unrealized Gains	0
Gross Unrealized Losses	(1,763)
Fair Value	356,303	478,629
Level 2 | Obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	1,130
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	1,130	5,875
Level 2 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	15,754	10,940
Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 50,696	$ 23,968