Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Summary of Significant Accounting Policies [Abstract]

Fair Value Measurements for Assets and Liabilities on Recurring Basis

The following table summarizes fair value measurements by level at December 31, 2014 for assets and liabilities measured

at fair value on a recurring basis:

(In thousands)	Level I		Level II		Level III			Total
Cash equivalents	$	31,159	$	—	$	—		$	31,159
Short-term investments		45,622		—		—			45,622
Warrant liability		—		—		(5,131	)		(5,131	)

The following table summarizes fair value measurements by level at December 31, 2013 for assets and liabilities measured

at fair value on a recurring basis:

(In thousands)	Level I		Level II		Level III			Total
Cash equivalents	$	10,281	$	—	$	—		$	10,281
Short-term investments		27,085		—		—			27,085
Warrant liabilities		—		—		(24,182	)		(24,182	)

Changes in Carrying Amounts of Warrant Liabilities

The changes in carrying amounts of warrant liabilities for the years ended December 31, 2014 and 2013 were as follows:

(In thousands)	2014			2013
Beginning balance		24,182			3,972
Net changes in valuation		(19,051	)		20,210
Ending balance		5,131			24,182