Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 334,077	$ 601,976
Available-for-sale marketable securities, Unrealized Gain	5,477	9,077
Available-for-sale marketable securities, Unrealized (Loss)	(718)	(213)
Available-for-sale marketable securities, Fair Market Value	338,836	610,840
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	91,937	70,418
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	77,707	257,132
Available-for-sale marketable securities, Unrealized Gain	551	1,330
Available-for-sale marketable securities, Unrealized (Loss)	(470)	(158)
Available-for-sale marketable securities, Fair Market Value	77,789	258,304
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	46,435	17,243
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	189,614	254,404
Available-for-sale marketable securities, Unrealized Gain	15	10
Available-for-sale marketable securities, Unrealized (Loss)	(9)	(1)
Available-for-sale marketable securities, Fair Market Value	189,620	254,413
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	22,784	12,173
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	52,266	76,129
Available-for-sale marketable securities, Unrealized Gain	4,863	7,539
Available-for-sale marketable securities, Unrealized (Loss)	(227)	(53)
Available-for-sale marketable securities, Fair Market Value	56,901	83,615
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	19,422	39,896
Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	7,928	8,413
Available-for-sale marketable securities, Unrealized Gain	43	152
Available-for-sale marketable securities, Fair Market Value	7,971	8,565
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	4,617	4,294
Available-for-sale marketable securities, Unrealized Gain	5	46
Available-for-sale marketable securities, Unrealized (Loss)	(12)	(1)
Available-for-sale marketable securities, Fair Market Value	4,610	4,339
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	3,296	1,106
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	1,356	979
Available-for-sale marketable securities, Fair Market Value	1,356	979
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	589	625
Available-for-sale marketable securities, Fair Market Value	$ 589	$ 625

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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