Net Loss Per Share (Schedule Of Basic And Diluted Net Loss Per Share Attributable To Common Stockholders) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Loss before income taxes	$ (13,371)	$ (55,200)	$ (10,242)	$ (72,588)
Income tax benefit	0	758	0	1,389
Net loss	$ (13,371)	$ (54,442)	$ (10,242)	$ (71,199)
Denominator:
Weighted average shares outstanding, basic and diluted	35,092,686	34,405,646	34,837,169	34,293,357
Net loss per share, basic and diluted	$ (0.38)	$ (1.58)	$ (0.29)	$ (2.08)