Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income (loss)	$ 6,231	$ 1,983	$ (3,686)	$ 446
Weighted-average shares outstanding — basic (in shares)	37,698	36,332	37,266	36,020
Effect of dilutive securities from stock award plans (in shares)	1,275	747	0	675
Weighted-average shares outstanding — diluted (in shares)	38,973	37,079	37,266	36,695
Net income (loss) per share - basic (in dollars per share)	$ 0.17	$ 0.05	$ (0.10)	$ 0.01
Net income (loss) per share - diluted (in dollars per share)	$ 0.16	$ 0.05	$ (0.10)	$ 0.01
Anti-dilutive weighted-average shares related to stock award plans (in shares)	1,383	326	3,757	1,255