v3.8.0.1
Document And Entity Information - shares
3 Months Ended
Sep. 30, 2017
Nov. 13, 2017
Document Information [Line Items]    
Entity Registrant Name NATURAL ALTERNATIVES INTERNATIONAL INC  
Entity Central Index Key 0000787253  
Trading Symbol naii  
Current Fiscal Year End Date --06-30  
Entity Filer Category Smaller Reporting Company  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Well-known Seasoned Issuer No  
Entity Common Stock, Shares Outstanding (in shares)   7,429,020
Document Type 10-Q  
Document Period End Date Sep. 30, 2017  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Amendment Flag false