Amount of annual base rent of leased assets, including but not limited to, offices and other facilities.

No definition available.

Name:	mitk_AnnualBaseRent
Namespace Prefix:	mitk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unamortized lease incentives.

+ References

No definition available.

+ Details

Name:	mitk_UnamortizedLeaseIncentives
Namespace Prefix:	mitk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Area of land held.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfLand
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

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

- Definition

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the lessee's operating lease.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

+ Details

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

- Definition

Carrying amount as of the balance sheet date of improvements having a life longer than one year that were made for the benefit of one or more tenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(f))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_TenantImprovements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_MajorPropertyClassAxis=us-gaap_BuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherCurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=mitk_IdCheckerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedContributionPlanNameAxis=mitk_DefinedContribution401KPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2015 USD ($) ft²	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2015 EUR (€) ft²
Loss Contingencies [Line Items]
Expiration date of term of lease	Jun. 30, 2019
Annual base rent	$ 471,000
Increased percentage of Company's annual base rent	3.00%			3.00%
Tenant improvement allowances	$ 675,690
Unamortized lease incentives	393,392
Rent expense for the Company's operating leases	$ 381,957	$ 368,835	$ 379,529
Building [Member]
Loss Contingencies [Line Items]
Amended office space subject to the lease \| ft²	22,523			22,523
Other current liabilities [Member]
Loss Contingencies [Line Items]
Unamortized lease incentives	$ 104,905
Other non-current liabilities [Member]
Loss Contingencies [Line Items]
Unamortized lease incentives	$ 288,487
ID Checker [Member]
Loss Contingencies [Line Items]
Expiration date of term of lease	May 31, 2020
Annual base rent \| €				€ 48,000
Standby letter of credit [Member]
Loss Contingencies [Line Items]
Standby letter of credit to the landlord	$ 210,000
Defined contribution 401 K Plan [Member]
Loss Contingencies [Line Items]
Employer contribution amount	$ 42,114	$ 0	$ 0