XML 96 R84.htm IDEA: XBRL DOCUMENT v3.21.1

Summary of Major Jurisdictions and Tax Year Subject to Examination Tax Authorities (Detail)	12 Months Ended
	Dec. 31, 2020
China
Income Tax Examination [Line Items]
Years Subject to Income Tax Examination	2017 and onward
HONG KONG
Income Tax Examination [Line Items]
Years Subject to Income Tax Examination	2017 and onward
Taiwan
Income Tax Examination [Line Items]
Years Subject to Income Tax Examination	2015 and onward
United States
Income Tax Examination [Line Items]
Years Subject to Income Tax Examination	2015 onward

X

- Definition

Income Tax Examination, Years Subject to Examination

+ References

No definition available.

+ Details

Name:	simo_IncomeTaxExaminationYearsSubjectToExamination
Namespace Prefix:	simo_
Data Type:	us-types:durationStringItemType
Balance Type:	na
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_IncomeTaxExaminationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	srt_StatementGeographicalAxis=country_CN
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=country_HK
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=country_TW
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: