v3.8.0.1

Fair Value Measurements - Schedule of Contingent Consideration Liability (Detail) - Contingent Consideration [Member] - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2017 | Sep. 30, 2016
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |  |
Contingent consideration liability, beginning balance | $ 14,517 |
Additions |  | $ 12,584
Fair value adjustments | (2,350) | 70
Interest accretion | 2,223 | 1,422
Foreign currency translation | 474 | 441
Contingent consideration liability, ending balance | $ 14,864 | $ 14,517

X
- Definition Fair value measurement with unobservable inputs reconciliation recurring basis liability foreign currency translation. + References No definition available. + Details
Name: | srdx_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityForeignCurrencyTranslation
Namespace Prefix: | srdx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value measurement with unobservable inputs reconciliation recurring basis liability interest accretion. + References No definition available. + Details
Name: | srdx_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityInterestAccretion
Namespace Prefix: | srdx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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

X
- Definition Amount of increase (decrease) 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_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- 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

X
- Details
Name: | us-gaap_InvestmentTypeAxis=srdx_ContingentConsiderationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |