Description of Business and Basis of Presentation (Net Income (Loss) per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Computation of Basic and Diluted Net Income (Loss) per Share [Line Items]
Net income (loss)	$ 2,167	$ (9,376)	$ (4,681)	$ (18,717)
Weighted average common shares outstanding	31,842	30,323	31,746	29,886
Weighted-average common shares outstanding, assuming dilution	32,027	30,323	31,746	29,886
Net income (loss) per share
Basic (in dollars per share)	$ 0.07	$ (0.31)	$ (0.15)	$ (0.63)
Diluted (in dollars per share)	$ 0.07	$ (0.31)	$ (0.15)	$ (0.63)
Outstanding options to purchase common stock
Computation of Basic and Diluted Net Income (Loss) per Share [Line Items]
Effect of potentially dilutive securities	0	0	0	0
Restricted stock awards
Computation of Basic and Diluted Net Income (Loss) per Share [Line Items]
Effect of potentially dilutive securities	9	0	0	0
Restricted stock unit awards
Computation of Basic and Diluted Net Income (Loss) per Share [Line Items]
Effect of potentially dilutive securities	168	0	0	0
Employee stock purchase plan
Computation of Basic and Diluted Net Income (Loss) per Share [Line Items]
Effect of potentially dilutive securities	8	0	0	0