Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

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, 2015 for assets and liabilities measured at fair value on a recurring basis:

(In thousands)	Level I		Level II		Level III			Total
Cash equivalents	$	20,673	$	—	$	—		$	20,673
Short-term investments		35,035		—		—			35,035
Warrant liability		—		—		(693	)		(693	)

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	)

Changes in Carrying Amounts of Warrant Liabilities

The changes in carrying amounts of the warrant liability for the years ended December 31,2015 and 2014 were as follows:

(In thousands)	2015			2014
Beginning balance	$	5,131		$	24,182
Net changes in valuation		(4,438	)		(19,051	)
Ending balance	$	693		$	5,131