Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

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 June 30, 2015 and December 31, 2014 are classified based on the valuation technique in the table below:

	June 30, 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	$	—	$	18,998	$	—	$	18,998
Money market accounts	34,021		—		—		34,021
Total assets at fair value	$	34,021	$	18,998	$	—	$	53,019

The above table excludes $18.6 million of cash held in banks.

	December 31, 2014
	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	$	—	$	42,981	$	—	$	42,981
Money market accounts	11,524		—		—		11,524
Total assets at fair value	$	11,524	$	42,981	$	—	$	54,505

Schedule of Short-Term Investments

Short-term Investments

	June 30, 2015
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
	(In thousands)
U.S. Treasury securities	$	18,993	$	5	$	—	$	18,998
Total	$	18,993	$	5	$	—	$	18,998

	December 31, 2014
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
	(In thousands)
U.S. Treasury securities	$	42,980	$	1	$	—	$	42,981
Total	$	42,980	$	1	$	—	$	42,981