Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income (loss)	$ 837	$ (1,159)	$ (9,917)	$ (1,537)
Weighted-average shares outstanding — basic (in shares)	37,250	35,987	37,046	35,864
Effect of dilutive securities from stock award plans (in shares)	1,120	0	0	0
Weighted-average shares outstanding — diluted (in shares)	38,370	35,987	37,046	35,864
Net income (loss) per share - basic (in dollars per share)	$ 0.02	$ (0.03)	$ (0.27)	$ (0.04)
Net income (loss) per share - diluted (in dollars per share)	$ 0.02	$ (0.03)	$ (0.27)	$ (0.04)
Anti-dilutive weighted-average shares related to stock award plans (in shares)	2,121	1,961	4,039	2,037