Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 211,596	$ 259,011
Available-for-sale marketable securities, Unrealized Gain	4,687	592
Available-for-sale marketable securities, Unrealized (Loss)	(262)	(2,967)
Available-for-sale marketable securities, Fair Market Value	216,021	256,636
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	23,999	191,978
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	93,267	41,133
Available-for-sale marketable securities, Unrealized Gain	4,081	432
Available-for-sale marketable securities, Unrealized (Loss)	(41)	(1,545)
Available-for-sale marketable securities, Fair Market Value	97,307	40,020
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	2,009	24,767
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	54,124	86,130
Available-for-sale marketable securities, Unrealized Gain	26	13
Available-for-sale marketable securities, Unrealized (Loss)	(1)	(26)
Available-for-sale marketable securities, Fair Market Value	54,149	86,117
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	1,391	85,094
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	42,167	110,969
Available-for-sale marketable securities, Unrealized Gain	431	112
Available-for-sale marketable securities, Unrealized (Loss)	(216)	(1,360)
Available-for-sale marketable securities, Fair Market Value	42,382	109,721
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	17,556	75,040
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	9,942	9,646
Available-for-sale marketable securities, Unrealized Gain	14	1
Available-for-sale marketable securities, Unrealized (Loss)	(4)	(36)
Available-for-sale marketable securities, Fair Market Value	9,952	9,611
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	3,043	7,077
Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	6,753	3,153
Available-for-sale marketable securities, Unrealized Gain	135	34
Available-for-sale marketable securities, Fair Market Value	6,888	3,187
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	4,751	7,604
Available-for-sale marketable securities, Unrealized Gain	0
Available-for-sale marketable securities, Fair Market Value	4,751	7,604
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	592	376
Available-for-sale marketable securities, Fair Market Value	$ 592	$ 376

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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