Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jul. 01, 2018	Apr. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ (3,732)	$ (11,469)	$ 7,788	$ (3,102)	$ (15,201)	$ 4,686
Weighted Average Number of Shares Outstanding, Basic	41,051,354		35,720,243		38,548,246	35,693,027
Weighted Average Number Diluted Shares Outstanding Adjustment	0		9,481,023		0	9,541,577
Basic net income (loss) per share	$ (0.09)		$ 0.17		$ (0.39)	$ 0.10
Shares used in computing diluted net income (loss) per share	41,051,354		45,201,266		38,548,246	45,234,604
Diluted net income (loss) per share	$ (0.09)		$ 0.17		$ (0.39)	$ 0.10
Shares excluded from diluted net loss per share computations	17,755,355		0		17,755,355	0
Net Income (Loss) Available to Common Stockholders, Basic	$ (3,732)		$ 6,053		$ (15,201)	$ 3,642
Restricted Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	0		139		0	83
Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	0		1,596		$ 0	$ 961
Retained Earnings [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ (3,732)		$ 7,788	$ (3,102)