Consolidated Statements of Equity - USD ($) $ in Thousands		Total	Common Stock [Member]		Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings (Accumulated Deficit) [Member]	Temporary Equity [Member]	Class B Common Stock [Member]	L Catterton [Member]	L Catterton [Member] Additional Paid-in Capital [Member]	L Catterton [Member] Temporary Equity [Member]	Mill Road Capital II, L.P. [Member]	Mill Road Capital II, L.P. [Member] Common Stock [Member]	Mill Road Capital II, L.P. [Member] Additional Paid-in Capital [Member]
Beginning balance, shares at Dec. 30, 2014			29,820,340		67,586
Beginning balance at Dec. 30, 2014		$ 140,115	$ 298		$ (2,848)	$ 120,929	$ 0	$ 21,736
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from exercise of stock options, warrants and employee stock purchase plan (in shares)	[1]		318,332
Proceeds from exercise of stock options, warrants and employee stock purchase plan		952	$ 3	[1]		949
Treasury shares acquired (in shares)					2,356,285
Treasury shares acquired, net		(35,000)			$ (32,152)	(2,848)
Stock-based compensation expense		1,698				1,698
Other		(94)				(94)
Net loss		(13,765)						(13,765)
Other comprehensive income (loss)		(134)					(134)
Ending balance at Dec. 29, 2015		93,772	$ 301	[1],[2]	$ (35,000)	120,634	(134)	7,971
Ending balance, shares at Dec. 29, 2015			30,138,672	[1]	2,423,871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from exercise of stock options, warrants and employee stock purchase plan (in shares)	[1]		162,253
Proceeds from exercise of stock options, warrants and employee stock purchase plan		1,100	$ 2	[1]		1,098
Stock-based compensation expense		2,540				2,540
Net loss		(71,677)						(71,677)
Other comprehensive income (loss)		83					83
Ending balance at Jan. 03, 2017		25,818	$ 303	[1],[2]	$ (35,000)	124,272	(51)	(63,706)
Ending balance, shares at Jan. 03, 2017			30,300,925	[1]	2,423,871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from exercise of stock options, warrants and employee stock purchase plan (in shares)			123,291	[1]											8,873,240
Proceeds from exercise of stock options, warrants and employee stock purchase plan		83	$ 1	[1]		82					$ 6,056	$ 6,056	$ 10,533	$ 29,110	$ 89	$ 29,021
Conversion of preferred stock to L Catterton (in shares)			4,252,873
Conversion of preferred stock to L Catterton		18,500	$ 43			18,457			$ (18,500)
Accretion of preferred stock		7,967				7,967			$ 7,967
Stock-based compensation expense		1,692				1,692
Net loss		(37,482)
Other comprehensive income (loss)		51					51
Ending balance at Jan. 02, 2018		$ 35,861	$ 436		$ (35,000)	$ 171,613	$ 0	$ (101,188)
Ending balance, shares at Jan. 02, 2018			43,550,329		2,423,871					1,522,098

[1] Unless otherwise noted, activity relates to Class A common stock

[2] Includes 1,522,098 shares of Class B common stock