Fair Value Disclosures (Tables)

12 Months Ended

Dec. 31, 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 December 31, 2016 and December 31, 2015 are listed in the table below:

	December 31, 2016						Total
	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)
	(In thousands)
Assets:
U.S. Treasury securities	$	—	$	32,907	$	—	$	32,907
Money market funds	32,031		—		—		32,031
Total assets at fair value	$	32,031	$	32,907	$	—	$	64,938

The above table excludes $24.8 million of cash held in banks.

	December 31, 2015						Total
	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)
	(In thousands)
Assets:
U.S. Treasury securities	$	—	$	39,918	$	—	$	39,918
Money market funds	14,032		—		—		14,032
Total assets at fair value	$	14,032	$	39,918	$	—	$	53,950

The above table excludes $11.0 million of cash held in banks.

Schedule of Short-term investments

Short-term Investments

	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

	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