Net Income (Loss) Per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Earnings Per Share [Abstract]        
Net loss $ (30,261) $ (13,373) $ (123,361) $ (42,379)
Weighted average shares outstanding used to compute basic and diluted net loss per share 75,647 72,089 74,743 71,341
Net loss per share - basic and diluted, USD per share $ (0.40) $ (0.19) $ (1.65) $ (0.59)
Antidilutive shares excluded from computation of diluted net loss 12,717 11,431 12,717 11,431