Annual report pursuant to Section 13 and 15(d)

Segment Information (Percentage Of Total Product Revenue Contributed By Company's Nutritional And Care Products) (Details)

v2.4.1.9
Segment Information (Percentage Of Total Product Revenue Contributed By Company's Nutritional And Care Products) (Details)
12 Months Ended
Jan. 03, 2015
Dec. 28, 2013
Dec. 29, 2012
USANA Nutritionals [Member]      
Revenue from External Customer [Line Items]      
Percentage of product revenue 79.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_UsanaNutritionalsMember
80.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_UsanaNutritionalsMember
80.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_UsanaNutritionalsMember
USANA Foods [Member]      
Revenue from External Customer [Line Items]      
Percentage of product revenue 13.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_UsanaFoodsMember
11.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_UsanaFoodsMember
11.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_UsanaFoodsMember
Sense - Beautiful Science [Member]      
Revenue from External Customer [Line Items]      
Percentage of product revenue 7.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_SenseBeautifulScienceMember
6.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_SenseBeautifulScienceMember
7.00%usna_PercentageOfProductRevenue
/ us-gaap_ProductOrServiceAxis
= usna_SenseBeautifulScienceMember