Nature of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Nature of Operations.
Net loss attributable to common shareholders	$ 10,238	$ 9,377	$ 30,568	$ 81,461	$ 88,600	$ 62,800	$ 31,900
Accumulated deficit	968,649		968,649		938,081
Net cash used in operating activities			37,296	31,025
Cash and cash equivalents	85,009	$ 156,462	85,009	$ 156,462	146,205	$ 5,027
Net working capital	$ 110,000		$ 110,000		$ 167,000