MARKETABLE SECURITIES (Tables)

6 Months Ended

Jun. 30, 2018

Marketable Securities [Abstract]

Schedule of Fair Value of Marketable Securities

At June 30, 2018 and December 31, 2017, the fair value of marketable securities are as follows:

	June 30, 2018		December 31, 2017
	(In thousands)
Available-for-sale marketable debt securities	$	119,746	$	4,995
Marketable equity security	664		—
Total marketable securities	$	120,410	$	4,995

Schedule of Current Available-for-sale Marketable Securities

At June 30, 2018, current available-for-sale marketable debt securities are as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Treasury discount notes	$	99,795	$	6	$	—	$	99,801
Commercial paper	19,945		—		—		19,945
Total available-for-sale marketable debt securities	$	119,740	$	6	$	—	$	119,746

At December 31, 2017, current available-for-sale marketable debt securities are as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Commercial paper	$	4,995	$	—	$	—	$	4,995
Total available-for-sale marketable debt securities	$	4,995	$	—	$	—	$	4,995

Schedule of Proceeds from Maturities and Sales of Available-for-sale Marketable Debt Securities

The following table presents the proceeds from maturities and sales of available-for-sale marketable debt securities:

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
	(In thousands)
Proceeds from maturities and sales of available-for-sale marketable debt securities	$	5,000	$	24,000	$	10,000	$	99,350