Earnings (Loss) Per Share (EPS) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Apr. 01, 2016
Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]
Net loss	$ (4,339)	$ (12,660)
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Basic	31,016,000	30,718,000
Denominator for diluted EPS	31,016,000	30,718,000
Basic EPS (in dollars per share)	$ (0.14)	$ (0.41)
Diluted EPS (in dollars per share)	$ (0.14)	$ (0.41)
Anitdilutive Securities Excluded From Earnings Per Share [Abstract]
Time-vested stock options, restricted stock and restricted stock units	1,700,000	1,890,000
Performance-vested stock options and restricted stock units	593,000	441,000