Document And Entity Information - shares	9 Months Ended
	Mar. 31, 2018	May 14, 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	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)		7,558,409
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false