Cash, Cash Equivalents and Investments - Components of Cash, Cash Equivalents and Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Cash	$ 185,624	$ 266,609
Money market instruments	537	2,464
Cash and cash equivalents	186,161	269,073
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	137,455	103,240
Non-current investments	583,748	395,125
Total	907,364	767,438
Treasury Bills [Member]
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	18,912	35,403
Long-term investments	39,753	96,458
Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	37,655	25,160
Long-term investments	43,940	67,058
Corporate Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	73,088	32,714
Long-term investments	481,218	203,428
Sovereign Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	0	8,660
Long-term investments	2,119	3,440
Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	4,998	1,303
Long-term investments	641	5,735
Agency Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Current investments, amortized cost of $137,124 and $102,258 in 2021 and 2020, respectively, allowance for credit losses of $0 in 2021 and 2020	2,802	0
Long-term investments	$ 16,077	$ 19,006

Cash, cash equivalents, short term and long term investments.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as noncurrent.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

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