Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Cumulative catch-up adjustment	Common Stock		Treasury Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit) Cumulative catch-up adjustment
Beginning balance (in shares) at Jan. 02, 2018				43,550,329	[1],[2]	2,423,871
Beginning balance at Jan. 02, 2018		$ 35,861	$ (1,506)	$ 436	[1],[2]	$ (35,000)	$ 171,613	$ (101,188)	$ (1,506)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with a public offering, net of transaction expenses (in shares)	[1],[2]			2,500,000
Issuance of common stock in connection with a public offering, net of transaction expenses		22,992		$ 25	[1],[2]		22,967
Stock plan transactions and other (in shares)	[1],[2]			302,980
Stock plan transactions and other		749		$ 3	[1],[2]		746
Stock-based compensation expense		3,026					3,026
Net (loss) income		(8,441)						(8,441)
Ending balance at Jan. 01, 2019		$ 52,681	$ (5,992)	$ 464	[2]	$ (35,000)	198,352	(111,135)	$ (5,992)
Ending balance (in shares) at Jan. 01, 2019				46,353,309	[2]	2,423,871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting standard, cumulative effect		us-gaap:AccountingStandardsUpdate201409Member
Stock plan transactions and other (in shares)	[2]			204,625
Stock plan transactions and other		$ (252)		$ 2	[2]		(254)
Stock-based compensation expense		2,487					2,487
Net (loss) income		1,647						1,647
Ending balance at Dec. 31, 2019		$ 50,571		$ 466	[2]	$ (35,000)	200,585	(115,480)
Ending balance (in shares) at Dec. 31, 2019				46,557,934	[2]	2,423,871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting standard, cumulative effect		us-gaap:AccountingStandardsUpdate201602Member
Stock plan transactions and other (in shares)	[2]			249,653
Stock plan transactions and other		$ (174)		$ 2	[2]		(176)
Stock-based compensation expense		2,561					2,561
Net (loss) income		(23,259)						(23,259)
Ending balance at Dec. 29, 2020		$ 29,699		$ 468	[2]	$ (35,000)	$ 202,970	$ (138,739)
Ending balance (in shares) at Dec. 29, 2020				46,807,587	[2]	2,423,871

[1] On May 24, 2018, 1,522,098 shares of Class B common stock were converted into the same number of the Company’s Class A common stock. As a result of the conversion, no shares of the Company’s Class B common stock are outstanding following the conversion.

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