Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)	$ 5,394	$ (4,562)	$ (5,528)	$ (19,416)
Weighted average common shares used in computing net income (loss) per share, basic (shares)	39,767	38,450	39,340	38,063
Effect of dilutive shares (shares)	1,203	0	0	0
Weighted average common shares used in computing net income (loss) per share, diluted (shares)	40,970	38,450	39,340	38,063
Net income (loss) per share, basic (dollars per share)	$ 0.14	$ (0.12)	$ (0.14)	$ (0.51)
Net income (loss) per share, diluted (dollars per share)	$ 0.13	$ (0.12)	$ (0.14)	$ (0.51)
Total shares excluded as anti-dilutive	0	6,473	6,196	6,473
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded as anti-dilutive	0	6,398	6,121	6,398
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares excluded as anti-dilutive	0	75	75	75