Document And Entity Information - shares	9 Months Ended
	Mar. 31, 2020	May 14, 2020
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 Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding (in shares)		6,788,366
Entity Shell Company	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Title of 12(b) Security	Common Stock, $0.01 par value per share