v3.10.0.1
Document And Entity Information - shares
3 Months Ended
Sep. 30, 2018
Nov. 13, 2018
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 Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company false  
Entity Small Business true  
Entity Common Stock, Shares Outstanding (in shares)   7,570,871
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Amendment Flag false