Defined Contribution Plans (Details) - 401 (K) Plan [Member] - USD ($)	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Minimum age required to participate in defined contribution plan	21 years
Minimum service period required to participate in defined contribution plan	6 months
Employer's matching contribution	50.00%
Employer's maximum contribution specified as percentage of employee compensation	6.00%
Matching contributions vesting period	5 years
Matching contribution, amount	$ 353,000	$ 347,000	$ 145,000

The vesting period of employer's matching contribution over the period.

No definition available.

Name:	mpaa_MatchingContributionsVestingPeriod
Namespace Prefix:	mpaa_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum age of employees who are eligible to cover under defined contribution plan service.

+ References

No definition available.

+ Details

Name:	mpaa_MinimumAgeRequiredToParticipateInDefinedContributionPlan
Namespace Prefix:	mpaa_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum service period of employees who are eligible to cover under defined contribution plan service.

+ References

No definition available.

+ Details

Name:	mpaa_MinimumServicePeriodRequiredToParticipateInDefinedContributionPlan
Namespace Prefix:	mpaa_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: