Represents the number of executive officers of the entity who are investors of the related party.

No definition available.

Name:	mosy_NumberOfExecutiveOfficersWhoAreInvestorsInRelatedParty
Namespace Prefix:	mosy_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of loan provided by executive officers to related party as a portion of the seed funding.

+ References

No definition available.

+ Details

Name:	mosy_RelatedPartyTransactionAmountOfLoanGivenByExecutiveOfficersToRelatedParty
Namespace Prefix:	mosy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of initial gross profits from the transactions with related party which will be retained by the reporting entity.

+ References

No definition available.

+ Details

Name:	mosy_RelatedPartyTransactionInitialGrossProfitFromTransactionsWithRelatedPartyToBeRetained
Namespace Prefix:	mosy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

Name:	us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mosy_CredoSemiconductorHongKongLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transactions (Details)	1 Months Ended	9 Months Ended
Related Party Transactions (Details)	Feb. 29, 2012 USD ($) item	Sep. 30, 2015 USD ($)	Mar. 04, 2015 item
Related party transactions
Number of executive officers who loaned a portion of seed funding to related parties \| item			2
Credo
Related party transactions
Number of executive officers who loaned a portion of seed funding to related parties \| item	2
Amount of loan provided by executive officers to related party	$ 250,000
Payment made to related party		$ 4,700,000
Initial amount of gross profits which will be retained by the entity		$ 3,600,000