Net Loss Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Net Loss Per Share Details
Net loss available for common shareholders - basic and diluted	$ (3,355)	$ (3,667)	$ (14,774)	$ (10,757)	$ (13,178)
Weighted-average shares outstanding - basic and diluted	43,858	28,448	40,605	26,739
Net loss per share - basic and diluted	$ (0.08)	$ (0.13)	$ (0.36)	$ (0.40)