Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Data (Unaudited) [Abstract]

Selected quarterly financial data

Set forth below is selected quarterly financial data for each of the quarters in the years ended December 31, 2014 and 2013.

	2014 Quarters Ended
(in thousands except per share amounts)	March 31			June 30			September 30			December 31
Operating loss	$	(5,059	)		(5,904	)		(5,054	)		(3,285	)
Change in fair value of warrant liability, net		(205	)		1,297			519			330
Net loss		(5,278	)		(4,600	)		(4,558	)		(2,945	)
Basic loss per share		(0.57	)		(0.49	)		(0.48	)		(0.31	)
Diluted loss per share		(0.57	)		(0.52	)		(0.48	)		(0.31	)

	2013 Quarters Ended
(in thousands except per share amounts)	March 31			June 30			September 30			December 31
Operating loss	$	(10,202	)		(10,587	)		(6,702	)		(5,526	)
Change in fair value of warrant liability, net		(2,272	)		5,115			(497	)		410
Net loss		(12,845	)		(5,482	)		(7,206	)		(4,792	)
Basic and diluted loss per share		(2.40	)		(0.91	)		(1.15	)		(0.63	)