FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of financial instruments measured at fair value on recurring basis

	December 31, 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	$	—	$	32,907	$	—	$	32,907
Money market accounts	32,031		—		—		32,031
Total assets at fair value	$	32,031	$	32,907	$	—	$	64,938

Financial instruments measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 are classified based on the valuation technique in the table below:

	September 30, 2017
	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	$	—	$	28,860	$	—	$	28,860
Money market accounts	6,114		—		—		6,114
Total assets at fair value	$	6,114	$	28,860	$	—	$	34,974

Schedule of short-term investments

Short-term Investments

	September 30, 2017
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
	(In thousands)
U.S. Treasury securities	$	28,881	$	—	$	(21	)	$	28,860
Total	$	28,881	$	—	$	(21	)	$	28,860

	December 31, 2016
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
	(In thousands)
U.S. Treasury securities	$	32,914	$	—	$	(7	)	$	32,907
Total	$	32,914	$	—	$	(7	)	$	32,907