The consideration received in connection with the license agreement and collaborative arrangement.

No definition available.

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

- Definition

Represents the reimbursement of prior payments for a mask set associated with the collaborative arrangement.

+ References

No definition available.

+ Details

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Namespace Prefix:	sigm_
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Balance Type:	debit
Period Type:	duration

- Definition

The reversal of the aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use due to the termination of a collaborative arrangement. Also includes the reversal of the company's share of net loss as described by the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	sigm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The amortization period of products acquired under a collaborative arrangement that have been capitalized.

+ References

No definition available.

+ Details

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Namespace Prefix:	sigm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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 210.5-02.14)
-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:	credit
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_CounterpartyNameAxis=sigm_TelechipsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=sigm_MaskSetsMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

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Note 13 - Subsequent Events (Details Textual) - USD ($) $ in Thousands		3 Months Ended
	Aug. 14, 2017	Oct. 28, 2017	Jul. 29, 2017	Jan. 28, 2017
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment			$ 72,673	$ 67,285
Collaborative Arrangement, Mask Set [Member] \| Telechips Inc [Member] \| Scenario, Forecast [Member]
Collaborative Arrangement, Reversal of Research and Development expense and Share of Net Loss Upon Termination		$ 900
Collaborative Arrangement, Mask Set [Member] \| Telechips Inc [Member] \| Mask Sets [Member]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment			$ 600
Subsequent Event [Member] \| Collaborative Arrangement, Mask Set [Member] \| Telechips Inc [Member]
Collaborative Arrangement, Consideration Received	$ 4,700
Collaborative Arrangement, Reimbursement of Prior Payments	$ 2,500
Products Acquired Under Collaborative Arrangement, Amortization Period	3 years