Net Income (Loss) per Share - Earnings 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
Earnings Per Share [Abstract]
Net income (loss)	$ (10,226)	$ 1,437	$ (23,966)	$ (3,298)
Denominator:
Weighted average common stock shares used in computing net income (loss) per share, basic (shares)	48,147	40,940	45,568	40,504
Effect of dilutive shares (shares)	0	1,194	0	0
Weighted average common stock shares used in computing net income (loss) per share, diluted (shares)	48,147	42,134	45,568	40,504
Net income (loss) per share, basic (usd per share)	$ (0.21)	$ 0.04	$ (0.53)	$ (0.08)
Net income (loss) per share, diluted (usd per share)	$ (0.21)	$ 0.03	$ (0.53)	$ (0.08)