Computation of Net Loss per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Computation of Net Loss per Share
Net loss attributable to common stockholders (in dollars)	$ (4,704)	$ (4,750)	$ (11,430)	$ (17,758)
Weighted average common shares outstanding used in computing basic and diluted net loss per share	111,701	109,074	111,191	108,573
Net loss per share
Basic and Diluted (in dollars per share)	$ (0.04)	$ (0.04)	$ (0.10)	$ (0.16)
Incremental shares excluded from the calculation of net loss per share (in shares)	4,296	4,383	4,550	2,620