Supplemental Disclosures to Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Jan. 02, 2018
Class of Stock [Line Items]
Interest paid (net of amounts capitalized)	$ 2,800	$ 3,800	$ 3,482
Income taxes (refunded) paid	(98)	42	(158)
Changes in purchases of property and equipment accrued in accounts payable, net	1,149	(1,339)	(842)
Common Stock | Class A common stock
Class of Stock [Line Items]
Conversion of Series A convertible preferred stock to common stock	$ 0	$ 0	$ 18,500