MARKETABLE SECURITITES (Tables)

6 Months Ended

Jun. 30, 2018

Marketable Securities [Abstract]

Available-for-sale Securities

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale (excluding cash equivalents) at June 30, 2018, were as follows:

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in 3 months or less:
Government securities	$	9,234	$	—	$	(5	)	$	9,229
Corporate securities	47,926		—		(58		)	47,868
Total	57,160		—		(63		)	57,097
Investments due in 4-12 months:
Corporate securities	21,981		—		(133		)	21,848
Total	21,981		—		(133		)	21,848
Investments due in 12 months or greater:
Corporate securities	19,792		—		(243		)	19,549
Total	19,792		—		(243		)	19,549
Total marketable securities	$	98,933	$	—	$	(439	)	$	98,494

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale (excluding cash equivalents) at December 31, 2017, were as follows:

	Amortized Cost		Gross Unrealized					Estimated Fair Market Value
(In thousands)			Gains		Losses
Investments due in 3 months or less:
Corporate securities	$	38,485	$	—	$	(16	)	$	38,469
Total	38,485		—		(16		)	38,469
Investments due in 4-12 months:
Corporate securities	104,440		—		(199		)	104,241
Government securities	9,302		—		(17		)	9,285
Total	113,742		—		(216		)	113,526
Investments due in 12 months or greater:
Corporate securities	37,436		—		(195		)	37,241
Total	37,436		—		(195		)	37,241
Total marketable securities	$	189,663	$	—	$	(427	)	$	189,236