Net Loss Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net Loss Per Share Details
Net loss available for common shareholders - basic and diluted	$ (3,845)	$ (7,790)	$ (18,619)	$ (26,002)
Weighted-average shares outstanding - basic and diluted	24,974	13,655	20,406	13,258
Net loss per share - basic and diluted	$ (0.15)	$ (0.57)	$ (0.91)	$ (1.96)