Quarterly report pursuant to Section 13 or 15(d)

Document And Entity Information

Document And Entity Information - shares
9 Months Ended
Sep. 29, 2018
Sep. 29, 2018
Nov. 02, 2018
Document And Entity Information [Abstract]      
Document Type   10-Q  
Amendment Flag   false  
Document Period End Date   Sep. 29, 2018  
Document Fiscal Period Focus   Q3  
Entity Central Index Key   0000896264  
Entity Registrant Name   USANA HEALTH SCIENCES INC  
Current Fiscal Year End Date   --12-29  
Document Fiscal Year Focus   2018  
Entity Filer Category   Large Accelerated Filer  
Entity Common Stock, Shares Outstanding     23,976,585
Trading Symbol   usna  
Entity Emerging Growth Company false    
Entity Small Business false