INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2015

Investments Schedule [Abstract]

Amortized Cost, Gross Unrealized Holding Gain or Loss, and Fair Value of Available For Sale Security by Major Security type

The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s available-for-sale securities by major security type at December 31, 2015 and 2014 are summarized in the tables below:

	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Aggregate Fair Value at December 31, 2015
Certificates of deposit	$	63,919	$	1	$	—		$	63,920
Corporate debt securities		358,625		20		(732	)		357,913
Commercial paper		12,733		—		—			12,733
U.S. government agency securities		186,882		—		(344	)		186,538
Greek government-issued bonds		48		79		—			127
Total	$	622,207	$	100	$	(1,076	)	$	621,231

	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Aggregate Fair Value at December 31, 2014
Certificates of deposit	$	72,302	$	1	$	—		$	72,303
Corporate debt securities		95,478		—		(342	)		95,136
Greek government-issued bonds		50		73		—			123
Total	$	167,830	$	74	$	(342	)	$	167,562

Fair Values of Available-For-Sale Securities by Contractual Maturity

The fair values of available-for-sale securities by contractual maturity were as follows:

	December 31,
	2015		2014
Maturing in one year or less	$	195,579	$	69,706
Maturing after one year through five years		425,652		97,856
Total	$	621,231	$	167,562