FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Fair value of marketable securities and investments

The fair-value hierarchy of the Company's cash equivalents and marketable securities at September 30, 2017, and December 31, 2016, was as follows:

	Fair Value Measurement at
	September 30, 2017
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Corporate securities	$	194,235	$	—	$	194,235
Commercial paper	12,575		—		12,575
Government securities	9,332		—		9,332
Money market funds	1,945		1,945		—
Total	$	218,087	$	1,945	$	216,142

	Fair Value Measurement at
	December 31, 2016
(In thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Corporate securities	$	132,141	$	—	$	132,141
Commercial paper	58,031		—		58,031
Money market funds	1,916		1,916		—
Total	$	192,088	$	1,916	$	190,172