Income (Loss) per Share (Calculation of Basic and Diluted Net Loss Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic and dilutive numerator:
Net income (loss)	$ 3,890	$ (3,008)	$ 13,274	$ (10,320)
Denominator:
Shares outstanding	45,398	45,310	45,132	44,920
Weighted-average shares outstanding—basic	45,398	45,310	45,132	44,920
Net effect of dilutive securities:
Incremental shares from equity awards	2,555		1,233
Weighted-average shares outstanding — diluted	47,953	45,310	46,365	44,920
Net income (loss) per share — basic	$ 0.09	$ (0.07)	$ 0.29	$ (0.23)
Net income (loss) per share — diluted	$ 0.08	$ (0.07)	$ 0.29	$ (0.23)