Net Income (Loss) per Common Share - Reconciliation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ 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 income (loss)	$ (35,051)	$ 567	$ (61,582)	$ (42,309)
Shares used in computing basic net income (loss) per common share	65,134,102	62,274,438	64,472,947	38,674,889
Add effect of dilutive securities:
Options to purchase common stock		8,514,752
Common stock warrants		936,928
Shares used in computing diluted net income (loss) per common share	65,134,102	71,726,118	64,472,947	38,674,889
Net income (loss) per common share, basic	$ (0.54)	$ 0.01	$ (0.96)	$ (1.09)
Net income (loss) per common share, diluted	$ (0.54)	$ 0.01	$ (0.96)	$ (1.09)