Income Taxes - Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2020	Dec. 31, 2019	Jan. 01, 2019
Income Tax Disclosure [Abstract]
Federal income tax (benefit) provision at federal rate	$ (4,867)	$ 368	$ (1,825)
State income tax (benefit) provision, net of federal tax	(1,191)	168	(623)
Other permanent differences	288	327	70
Tax credits	(390)	(408)	(602)
Change in valuation allowance	6,104	(913)	2,600
Tax rate change	(25)	23	(248)
Deferred tax asset write-off	157	566	212
Other items, net	8	(27)	168
Total provision (benefit) for income taxes	$ 84	$ 104	$ (248)
Effective income tax rate	(0.40%)	5.90%	2.90%