FINANCIAL INSTRUMENTS (Tables)

9 Months Ended

Sep. 30, 2019

Investments, Debt and Equity Securities [Abstract]

Schedule of Cash, Cash Equivalents and Available-for-Sale Securities by Significant Investment Category

The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category as of September 30, 2019 and December 31, 2018, respectively:



As of September 30, 2019	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Aggregate Fair Value		Cash and Cash Equivalents		Short-term Marketable Securities ⁽¹⁾		Long-term Marketable Securities ⁽²⁾
Level 1:
Cash	$	294,543	$	—	$	—		$	294,543	$	294,543	$	—	$	—

Level 2:
Money market instruments	128,678		—		—			128,678		128,678		—		—
Corporate debt securities	519,693		3,713		(67		)	523,339		—		206,782		316,557
U.S. government agency securities	204,371		1,073		(97		)	205,347		—		90,790		114,557
Foreign and other	549		142		(1		)	690		—		—		690
Subtotal	853,291		4,928		(165		)	858,054		128,678		297,572		431,804
Total	$	1,147,834	$	4,928	$	(165	)	$	1,152,596	$	423,220	$	297,572	$	431,804



As of December 31, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Aggregate Fair Value		Cash and Cash Equivalents		Short-term Marketable Securities ⁽¹⁾		Long-term Marketable Securities⁽²⁾
Level 1:
Cash	$	228,809	$	—	$	—		$	228,809	$	228,809	$	—	$	—

Level 2:
Money market instruments	205,736		—		—			205,736		205,736		—		—
Corporate debt securities	564,852		214		(2,288		)	562,778		2,000		376,545		184,233
Commercial paper	77,702		—		—			77,702		21,964		55,738		—
U.S. government agency securities	240,436		144		(697		)	239,883		31,474		156,967		51,442
Foreign and other	5,126		139		(1		)	5,264		3,999		1,076		189
Subtotal	1,093,852		497		(2,986		)	1,091,363		265,173		590,326		235,864
Total	$	1,322,661	$	497	$	(2,986	)	$	1,320,172	$	493,982	$	590,326	$	235,864

(1) The Company’s short-term marketable securities mature in one year or less.

(2) The Company’s long-term marketable securities mature between one and five years.