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
	Mar. 31, 2016	Mar. 31, 2015
Basic and dilutive numerator:
Net income (loss)	$ 2,489	$ (665)
Denominator:
Shares outstanding	45,041	44,601
Weighted-average shares outstanding—basic	45,041	44,601
Net effect of dilutive securities:
Stock options	405
Weighted-average shares outstanding—diluted	46,810	44,601
Net loss per share—basic (in Dollars per share)	$ 0.06	$ (0.01)
Net loss per share—diluted (in Dollars per share)	$ 0.05	$ (0.01)
Restricted Stock Units (RSUs)
Net effect of dilutive securities:
Contingently issuable shares	1,302
Employee Stock Purchase Plan (ESPP)
Net effect of dilutive securities:
Contingently issuable shares	62