Schedule of Computation of Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income	$ 13,757	$ 2,585	$ 30,792	$ 3,543
Denominator:
Weighted-average shares used to compute basic net income per share	113,603	110,652	113,242	110,118
Dilutive effect of employee stock options	12,048	5,767	10,175	5,045
Weighted-average shares used to compute diluted net income per share	125,651	116,419	123,417	115,163
Net income per share attributable to common stockholders
Basic	$ 0.12	$ 0.02	$ 0.27	$ 0.03
Diluted	$ 0.11	$ 0.02	$ 0.25	$ 0.03