Basic and Diluted Net Income (Loss) Per Share - Earnings (Loss) Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ (4,119)	$ (8,211)	$ (11,172)	$ (18,645)
Weighted average shares used to calculate net income (loss) per share, basic	36,741	36,096	36,695	32,980
Weighted average shares used to calculate net income (loss) per share, diluted	36,741	36,096	36,695	32,980
Basic (in dollars per share)	$ (0.11)	$ (0.23)	$ (0.30)	$ (0.57)
Diluted (in dollars per share)	$ (0.11)	$ (0.23)	$ (0.30)	$ (0.57)
Restricted Stock Units (RSUs) [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive equity awards	0	0	0	0
Stock Options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive equity awards	0	0	0	0