Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017	Dec. 31, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 3,611	$ 2,795	$ 8,297	$ 3,238	$ 7,159
Net income (loss) available to common stockholders	$ 2,808	$ 2,173	$ 6,449	$ 2,515
Basic weighted average common shares outstanding	35,735,680	35,431,806	35,707,245	35,410,482
Basic net income (loss) per share	$ 0.08	$ 0.06	$ 0.18	$ 0.07
Dilutive effect of preferred stock and non-vested shares	9,674,876	9,505,835	9,586,010	9,555,782
Shares used in computing diluted net income (loss) per share	45,410,556	44,937,641	45,293,255	44,966,264
Diluted net income (loss) per share	$ 0.08	$ 0.06	$ 0.18	$ 0.07
Restricted Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Less: Income attributable to participating securities	$ (63)	$ (45)	$ (147)	$ (54)
Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Less: Income attributable to participating securities	$ (740)	$ (577)	$ (1,701)	$ (669)