Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Jun. 29, 2012	Jul. 01, 2011
Contingent consideration [Member]
Changes in financial liabilities with inputs classified within Level 3 of the fair value
Changes in financial liabilities with inputs classified within Level 3 of the fair value, beginning balance	$ 25,502	$ 29,300
Net Realized/Unrealized Losses (Gains) Included in Earnings	(977)	660
Purchases and Issuances		4,817
Sales and Settlements	(15,000)	(8,825)
Transfers in and/or (out) of Level 3
Changes in financial liabilities with inputs classified within Level 3 of the fair value, ending balance	9,525	25,952
Common stock warrant liability [Member]
Changes in financial liabilities with inputs classified within Level 3 of the fair value
Changes in financial liabilities with inputs classified within Level 3 of the fair value, beginning balance	10,736
Net Realized/Unrealized Losses (Gains) Included in Earnings	2,791	10,241
Purchases and Issuances		5,656
Sales and Settlements
Transfers in and/or (out) of Level 3
Changes in financial liabilities with inputs classified within Level 3 of the fair value, ending balance	13,527	15,897
Class B conversion liability [Member]
Changes in financial liabilities with inputs classified within Level 3 of the fair value
Changes in financial liabilities with inputs classified within Level 3 of the fair value, beginning balance	81,378
Net Realized/Unrealized Losses (Gains) Included in Earnings	44,119	57,051
Purchases and Issuances		41,641
Sales and Settlements	(125,497)
Transfers in and/or (out) of Level 3
Changes in financial liabilities with inputs classified within Level 3 of the fair value, ending balance		$ 98,692

Fair value measurement with unobservable inputs reconciliation recurring basis liability purchases and issuances.

No definition available.

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Balance Type:	credit
Period Type:	duration

- Definition

Fair value measurement with unobservable inputs reconciliation recurring basis liability sales and settlement.

+ References

No definition available.

+ Details

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Namespace Prefix:	mtsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Period Type:	duration

- Definition

Amount of net transfers into and out of financial instruments classified in shareholders' equity measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

+ Details

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

- Definition

Amount of gain (loss) recognized in earnings, arising from liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

+ 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=7578670&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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- Definition

This element represents a liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

+ Details

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