Net Loss Per Common Share (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Schedule of Securities Excluded from Computation of Diluted Loss Per Share

Securities excluded from the calculation of diluted loss per share are shown in the chart below:

	Years ended December 31,
(in thousands)	2015		2014		2013
Common stock warrants		—		2,381		2,777
Outstanding options to purchase common stock		19,211		19,567		20,107
Conversion of the Convertible Notes		25,000		25,000		25,000