XML 53 R29.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Investments - Additional Information (Detail) (USD $) | 12 Months Ended
--- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2011
Investments Debt And Equity Securities [Abstract] |  |  |
Maturity of short-term investments | Greater than 90 days and less than one year | Greater than 90 days and less than one year |
Maturity of long-term investments | Greater than one year | Greater than one year |
Other-than-temporary impairment charges recognized | $ 0 | $ 0 | $ 0

X
- Definition Maturity of long-term investments. + References No definition available. + Details
Name: | mitk_MaturityOfLongTermInvestments
Namespace Prefix: | mitk_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maturity of short-term investments. + References No definition available. + Details
Name: | mitk_MaturityOfShortTermInvestments
Namespace Prefix: | mitk_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -URI http://asc.fasb.org/extlink&oid=27724398&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration