Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Unobservable Input Reconciliation) (Details)

v2.4.1.9
Fair Value Measurements (Unobservable Input Reconciliation) (Details) (USD $)
In Thousands, unless otherwise specified
9 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fiscal year opening balance $ 1,852us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent    
Accretion expense of contingent consideration payable (36)us-gaap_AccretionExpense (234)us-gaap_AccretionExpense  
Fair value revision of contingent consideration payable (1,888)mpet_FairValueRevisionofContingentConsiderationPayable 0mpet_FairValueRevisionofContingentConsiderationPayable  
Ending balance 0us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent    
Recurring | Level 3      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Business Combination, Contingent Consideration, Liability     1,852us-gaap_BusinessCombinationContingentConsiderationLiability
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
Accretion expense of contingent consideration payable (36)us-gaap_AccretionExpense
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
   
Fair value revision of contingent consideration payable (1,888)mpet_FairValueRevisionofContingentConsiderationPayable
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
   
Ending balance $ 0us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember