Refers to contingent consideration current at fair value disclosure.

No definition available.

Name:	mpaa_ContingentConsiderationCurrentAtFairValueDisclosure
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Refers to contingent consideration noncurrent at fair value disclosure.

+ References

No definition available.

+ Details

Name:	mpaa_ContingentConsiderationNoncurrentAtFairValueDisclosure
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of deferred compensation liability as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	mpaa_DeferredCompensationFairValueDisclosure
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of likelihood of a future event, used as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	mpaa_FairValueInputsProbabilityOfFutureEvent
Namespace Prefix:	mpaa_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

+ References

No definition available.

+ Details

Name:	mpaa_WarrantLiabilityFairValueDisclosure
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

+ Details

Name:	us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedDividendRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsRiskFreeInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

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

- Definition

Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityTransfersNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

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

- Definition

Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ 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(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560

Reference 6: 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(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 8: 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

+ Details

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

- References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=mpaa_SupplierWarrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=mpaa_ContingentConsiderationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value Measurements (Details) - USD ($)	3 Months Ended		9 Months Ended
Fair Value Measurements (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2016
Forward Foreign Currency Exchange Contracts [Member]
Other liabilities [Abstract]
Net loss on forward foreign currency exchange contracts	$ (964,000)	$ 245,000	$ (2,150,000)	$ (104,000)
Supplier Warrant [Member]
Fair value assumptions of warrants [Abstract]
Risk free interest rate			0.74%
Expected life in years			9 months
Expected volatility			39.90%
Dividend yield			0.00%
Probability of future financing			0.00%
Change in warrant liability measured at fair value recurring basis using significant unobservable inputs (Level 3) [Rollforward]
Beginning balance	10,878,000	12,248,000	$ 15,643,000	10,506,000
Newly issued	0	0	0	0
Total (gain) loss included in net income (loss)	(962,000)	1,275,000	(5,727,000)	3,017,000
Exercises/settlements	0	0	0	0
Net transfers in (out) of Level 3	0	0	0	0
Ending balance	9,916,000	13,523,000	9,916,000	13,523,000
Contingent Consideration [Member]
Change in warrant liability measured at fair value recurring basis using significant unobservable inputs (Level 3) [Rollforward]
Beginning balance	0	1,340,000	330,000	0
Newly issued	0	0	0	1,320,000
Total (gain) loss included in net income (loss)	0	40,000	(16,000)	60,000
Exercises/settlements	0	0	(314,000)	0
Net transfers in (out) of Level 3	0	0	0	0
Ending balance	0	$ 1,380,000	0	$ 1,380,000
Recurring [Member]
Short-term investments [Abstract]
Mutual funds	1,966,000		1,966,000		$ 1,813,000
Accrued liabilities [Abstract]
Contingent consideration	0		0		224,000
Other current liabilities [Abstract]
Deferred compensation	1,966,000		1,966,000		1,813,000
Forward foreign currency exchange contracts	2,566,000		2,566,000		416,000
Other liabilities [Abstract]
Warrant liability	9,916,000		9,916,000		15,643,000
Contingent consideration	0		0		106,000
Recurring [Member] \| Level 1 [Member]
Short-term investments [Abstract]
Mutual funds	1,966,000		1,966,000		1,813,000
Accrued liabilities [Abstract]
Contingent consideration	0		0		0
Other current liabilities [Abstract]
Deferred compensation	1,966,000		1,966,000		1,813,000
Forward foreign currency exchange contracts	0		0		0
Other liabilities [Abstract]
Warrant liability	0		0		0
Contingent consideration	0		0		0
Recurring [Member] \| Level 2 [Member]
Short-term investments [Abstract]
Mutual funds	0		0		0
Accrued liabilities [Abstract]
Contingent consideration	0		0		0
Other current liabilities [Abstract]
Deferred compensation	0		0		0
Forward foreign currency exchange contracts	2,566,000		2,566,000		416,000
Other liabilities [Abstract]
Warrant liability	0		0		0
Contingent consideration	0		0		0
Recurring [Member] \| Level 3 [Member]
Short-term investments [Abstract]
Mutual funds	0		0		0
Accrued liabilities [Abstract]
Contingent consideration	0		0		224,000
Other current liabilities [Abstract]
Deferred compensation	0		0		0
Forward foreign currency exchange contracts	0		0		0
Other liabilities [Abstract]
Warrant liability	9,916,000		9,916,000		15,643,000
Contingent consideration	$ 0		$ 0		$ 106,000