Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v2.4.1.9
Stockholders' Equity - Additional Information (Detail) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Stockholders Equity [Line Items]    
Common stock, shares issued 37,072,155us-gaap_CommonStockSharesIssued 36,918,442us-gaap_CommonStockSharesIssued
Common stock, shares outstanding 37,072,155us-gaap_CommonStockSharesOutstanding 36,918,442us-gaap_CommonStockSharesOutstanding
Common stock share, par value 0.0001us-gaap_CommonStockParOrStatedValuePerShare 0.0001us-gaap_CommonStockParOrStatedValuePerShare
Preferred stock, shares authorized 25,000,000us-gaap_PreferredStockSharesAuthorized 25,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, par value 0.0001us-gaap_PreferredStockParOrStatedValuePerShare 0.0001us-gaap_PreferredStockParOrStatedValuePerShare
Preferred stock, shares issued 0us-gaap_PreferredStockSharesIssued 0us-gaap_PreferredStockSharesIssued
Preferred stock, shares outstanding 0us-gaap_PreferredStockSharesOutstanding 0us-gaap_PreferredStockSharesOutstanding
Restricted Stock [Member] | Non-employee directors [Member]    
Stockholders Equity [Line Items]    
Common stock issued 42,882us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= mmi_NonEmployeeDirectorMember
42,882us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_TitleOfIndividualAxis
= mmi_NonEmployeeDirectorMember