Net Income (Loss) Per Share (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]    
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 11,589 12,061
Net loss $ (10,027) $ (5,629)
Weighted average shares outstanding used to compute basic and diluted net loss per share 70,490 63,444
Net loss per share, basic and diluted $ (0.14) $ (0.09)