Segment Information (Schedule Of Revenue Percentage By Product) (Details)	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
USANA Nutritionals [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	82.00%	83.00%	83.00%
USANA Foods [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	9.00%	9.00%	10.00%
Sense - Beautiful Science [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	3.00%	6.00%	6.00%
Celavive [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	5.00%