Related Party Transactions - Additional Information (Detail) $ / shares in Units, $ in Thousands		12 Months Ended
Dec. 22, 2014 Individual $ / shares shares	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Related Party Transaction [Line Items]
Fees incurred to law firm		$ 122	$ 236
Accrued liabilities for unbilled services		25	15
Outstanding loan amount		26	26
Warrant [Member]
Related Party Transaction [Line Items]
Number of individual issued warrants \| Individual	2
Warrants issued to individuals \| shares	74,802
Exercise price of warrant \| $ / shares	$ 14.00
Warrants expiration date	5 years
MediaMission Holding B.V. [Member]
Related Party Transaction [Line Items]
Amount payable, total		$ 114	$ 370

Class of warrant or right issued.

No definition available.

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Namespace Prefix:	sofo_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Classes or warrant right expiration period.

+ References

No definition available.

+ Details

Name:	sofo_ClassesOrWarrantRightExpirationPeriod
Namespace Prefix:	sofo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of individual to whom warrants issued.

+ References

No definition available.

+ Details

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Namespace Prefix:	sofo_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Accrued liabilities for unbilled services.

+ References

No definition available.

+ Details

Name:	sofo_RelatedPartyTransactionAccruedLiabilitiesForUnbilledServices
Namespace Prefix:	sofo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount for accounts payable to related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.17)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k)(1))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amounts due from owners or affiliates of the reporting entity related to issuance of the entity's capital stock before cash payment is received (does not include amounts due from officers or directors). This element would also include the receivable for proceeds from the issuance of shares under employee stock option exercises which proceeds have not been received as of the reporting date due to the timing of the transaction date versus the settlement date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k)(1))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29,30)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

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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

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=sofo_MediaMissionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: