Cash, Cash Equivalents and Investments - Amortized Cost to Fair Value (Detail) $ in Thousands	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 725,105
Gross Unrealized Gains	1,069
Gross Unrealized Losses	(4,971)
Fair Value, Total	721,203
Treasury Bills [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Total	58,665
Treasury Bills [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,864
Gross Unrealized Gains	51
Gross Unrealized Losses	(3)
Fair Value, Total	18,912
Treasury Bills [Member] \| Long-term investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	39,740
Gross Unrealized Gains	46
Gross Unrealized Losses	(33)
Fair Value, Total	39,753
Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Total	81,595
Asset-Backed Securities [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	37,568
Gross Unrealized Gains	112
Gross Unrealized Losses	(25)
Fair Value, Total	37,655
Asset-Backed Securities [Member] \| Long-term investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	44,197
Gross Unrealized Gains	45
Gross Unrealized Losses	(302)
Fair Value, Total	43,940
Corporate Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Total	554,306
Corporate Bonds [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	72,863
Gross Unrealized Gains	251
Gross Unrealized Losses	(26)
Fair Value, Total	73,088
Corporate Bonds [Member] \| Long-term investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	485,140
Gross Unrealized Gains	555
Gross Unrealized Losses	(4,477)
Fair Value, Total	481,218
Sovereign Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Total	2,119
Sovereign Bonds [Member] \| Long-term investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,141
Gross Unrealized Gains	0
Gross Unrealized Losses	(22)
Fair Value, Total	2,119
Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Total	5,639
Municipal Bonds [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,029
Gross Unrealized Gains	1
Gross Unrealized Losses	(32)
Fair Value, Total	4,998
Municipal Bonds [Member] \| Long-term investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	635
Gross Unrealized Gains	6
Gross Unrealized Losses	0
Fair Value, Total	641
Agency Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Total	18,879
Agency Bonds [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,800
Gross Unrealized Gains	2
Gross Unrealized Losses	0
Fair Value, Total	2,802
Agency Bonds [Member] \| Long-term investments [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	16,128
Gross Unrealized Gains	0
Gross Unrealized Losses	(51)
Fair Value, Total	$ 16,077

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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