FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2016

Fair Value Disclosures [Abstract]

Schedule of financial instruments measured at fair value on recurring basis

Financial instruments measured at fair value on a recurring basis as of September 30, 2016 and December 31, 2015 are classified based on the valuation technique in the table below:

	September 30, 2016
	Fair value measurements using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(In thousands)
Assets:
U.S. Treasury securities	$	—	$	32,931	$	—	$	32,931
Money market accounts	34,009		—		—		34,009
Total assets at fair value	$	34,009	$	32,931	$	—	$	66,940

	December 31, 2015
	Fair value measurements using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(In thousands)
Assets:
U.S. Treasury securities	$	—	$	39,918			$	39,918
Money market accounts	14,032		—		—		14,032
Total assets at fair value	$	14,032	$	39,918	$	—	$	53,950

Schedule of short-term investments

Short-term Investments

	September 30, 2016
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
	(In thousands)
U.S. Treasury securities	$	32,914	$	17	$	—	$	32,931
Total	$	32,914	$	17	$	—	$	32,931

	December 31, 2015
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
	(In thousands)
U.S. Treasury securities	$	39,933	$	—	$	(15	)	$	39,918
Total	$	39,933	$	—	$	(15	)	$	39,918