Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

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, 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	)

The following table summarizes fair value measurements by level at December 31, 2012 for assets and liabilities measured

at fair value on a recurring basis:

(In thousands)	Level I		Level II		Level III			Total
Cash equivalents	$	13,188	$	—	$	—		$	13,188
Short-term investments		24,000		—		—			24,000
Warrant liabilities		—		—		(3,972	)		(3,972	)

Changes in Carrying Amounts of Warrant Liabilities

The changes in carrying amounts of warrant liabilities for the year ended December 31, 2013 and 2012, were as follows:

(In thousands)	2013		2012
Beginning balance		3,972		6,739
Net changes in valuation		20,210		(2,767	)
Ending balance		24,182		3,972