XML 46 R34.htm IDEA: XBRL DOCUMENT v3.21.1

Short-Term Investments (Tables)

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Short Term Investments

		December 31
		2019				2020
		US$				US$
Trading securities			2,010				—

X

- Definition

Disclosure of short term investments

+ References

No definition available.

+ Details

Name:	simo_ShortTermInvestmentsTextBlock
Namespace Prefix:	simo_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

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