FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2015

FAIR VALUE MEASUREMENTS.

Schedule of financial assets subject to fair value measurements

	As of December 31, 2014		Level 1		Level 2		Level 3
	(In thousands)
Money market funds and cash equivalents	$	18,677		—	$	18,677		—
Marketable securities	$	173,023		—	$	173,023		—
	$	191,700		—	$	191,700		—

	As of December 31, 2015		Level 1		Level 2		Level 3
	(In thousands)
Money market funds and cash equivalents	$	59,831		—	$	59,831		—
Marketable securities	$	217,781		—	$	217,781		—
	$	277,612		—	$	277,612		—