Net Income (Loss) Per Share - Computation of Basic and Diluted Net Income (Loss) Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income (loss)	$ (65,145)	$ 5,450	$ (73,783)	$ (343)
Denominator (basic):
Weighted average common shares outstanding	95,340,136	92,924,516	94,659,931	92,436,628
Denominator (diluted):
Dilutive stock options outstanding	0	3,136,115	0	0
Dilutive restricted stock units and awards	0	152,357	0	0
Dilutive shares purchased under ESPP	0	6,115	0	0
Weighted average common shares from warrants	0	2,304,931	0	0
Net weighted average common shares outstanding	95,340,136	98,524,034	94,659,931	92,436,628
Net income (loss) per share:
Basic (in dollars per share)	$ (0.68)	$ 0.06	$ (0.78)	$ 0.00
Diluted (in dollars per share)	$ (0.68)	$ 0.06	$ (0.78)	$ 0.00