Represents the reduction of the term of an operating lease contract as a result of an early termination.

No definition available.

Name:	naii_LesseeOperatingLeaseReductionOfTermOfContract
Namespace Prefix:	naii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Area of leased facility in square feet.

+ References

No definition available.

+ Details

Name:	naii_OperatingLeaseFacilityArea
Namespace Prefix:	naii_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase (decrease) in obligation for operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(1)
-SubTopic 20
-Topic 842
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

Name:	us-gaap_IncreaseDecreaseInOperatingLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-4

+ Details

Name:	us-gaap_OperatingLeaseExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_LeaseContractualTermAxis=naii_VistaCaliforniaManufacturingFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseContractualTermAxis=naii_EarlyTerminationOfLuganoSwitzerlandApartmentLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=naii_California1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_CH
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=naii_NaturalAlternativesInternationalEuropeSaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=naii_SofinolSaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note J - Commitments (Details Textual) $ in Millions		12 Months Ended
Note J - Commitments (Details Textual) $ in Millions	Jan. 26, 2024 USD ($)	Jun. 30, 2025 USD ($) ft²	Jun. 30, 2024 USD ($) ft²	Jan. 22, 2024	Jul. 18, 2023	Nov. 05, 2018
Lessee, Operating Lease, Term of Contract (Month)				27 months
Operating Lease, Expense \| $		$ 5.5	$ 5.4
Vista, California Manufacturing Facility [Member]
Lessee, Operating Lease, Renewal Term (Year)					10 years 5 months 1 day
Early Termination of Lugano, Switzerland Apartment Lease [Member]
Lessee, Operating Lease, Reduction of Term of Contract (Year)	9 years 8 months 1 day
Increase (Decrease) in Operating Lease Liability \| $	$ (0.3)
California 1 [Member]
Operating Lease Facility Area (Square Foot)			162,000
SWITZERLAND \| Natural Alternatives International Europe SA [Member]
Operating Lease Facility Area (Square Foot)		116,000
Lessee, Operating Lease, Renewal Term (Year)		10 years
SWITZERLAND \| Natural Alternatives International Europe SA [Member] \| Sofinol SA [Member]
Operating Lease Facility Area (Square Foot)		2,870
Lessee, Operating Lease, Term of Contract (Month)						5 years