Gain on Sale of Software Product - Additional Information (Detail) - USD ($)	1 Months Ended	9 Months Ended
Jun. 30, 2019	Sep. 30, 2019
Income Statement Balance Sheet and Additional Disclosures by Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sale of software product		$ 363,000
Gain on sale of software product		$ 483,000
Asset Purchase Agreement [Member] \| Poser 3D Software Product [Member] \| Bondware, Inc. [Member]
Income Statement Balance Sheet and Additional Disclosures by Disposal Groups Including Discontinued Operations [Line Items]
Consideration for sale of asset	$ 500,000
Proceeds from sale of software product	$ 350,000
Remaining consideration payment period	3 years
Gain on sale of software product	$ 483,000

Consideration for sale of productive asset.

No definition available.

Name:	smsi_ConsiderationForSaleOfProductiveAsset
Namespace Prefix:	smsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Remaining consideration payment period.

+ References

No definition available.

+ Details

Name:	smsi_RemainingConsiderationPaymentPeriod
Namespace Prefix:	smsi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnDispositionOfAssets1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the sale of property, plant and equipment (capital expenditures), software, and other intangible assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfProductiveAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_TypeOfArrangementAxis=smsi_AssetPurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=smsi_Poser3DSoftwareProductMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=smsi_BondwareIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: