Net Income (Loss) per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income (loss)	$ (6,280)	$ 2,239	$ (13,740)	$ (4,735)
Weighted average common stock shares used in computing net income (loss) per share, basic (shares)	47,232	40,495	44,258	40,283
Effect of dilutive shares (shares)	0	1,073	0	0
Weighted average common stock shares used in computing net income (loss) per share, diluted (shares)	47,232	41,568	44,258	40,283
Net income (loss) per share, basic (usd per share)	$ (0.13)	$ 0.06	$ (0.31)	$ (0.12)
Net income (loss) per share, diluted (usd per share)	$ (0.13)	$ 0.05	$ (0.31)	$ (0.12)