FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2018

Schedule of financial instruments measured at fair value on recurring basis



	December 31, 2017
	Fair value measurements using
(in thousands)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
U.S. Treasury securities	$	—	$	21,916	$	—	$	21,916
Money market accounts	1,117		—		—		1,117
Total assets at fair value	$	1,117	$	21,916	$	—	$	23,033

Financial instruments measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017 are classified based on the valuation technique in the table below:



	September 30, 2018
	Fair value measurements using
(in thousands)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
U.S. Treasury securities	$	—	$	17,835	$	—	$	17,835
Money market accounts	86,983		—		—		86,983
Total assets at fair value	$	86,983	$	17,835	$	—	$	104,818

Schedule of short-term investments

Short-term Investments



	September 30, 2018
(in thousands)	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. Treasury securities	$	17,850	$	—	$	(15	)	$	17,835
Total	$	17,850	$	—	$	(15	)	$	17,835



	December 31, 2017
(in thousands)	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. Treasury securities	$	21,939	$	—	$	(23	)	$	21,916
Total	$	21,939	$	—	$	(23	)	$	21,916