v3.21.2

Summary of significant accounting policies (Schedule of Changes in Financial Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of significant accounting policies
Balance, beginning	$ 253	$ 286	$ 680
Change in fair value of warrant derivative liability	(4)	(33)	(394)	$ 150
Change In Financial Liabilities Issuance Of Warrants				530
Balance, ending	$ 249	$ 253	$ 286	$ 680

X

- Definition

Change in financial liabilities as result of change in fair value of warrant derivative liability.

+ References

No definition available.

+ Details

Name:	sgoc_ChangeInFinancialLiabilitiesChangeInFairValueOfWarrantDerivativeLiability
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Change in financial liabilities as result of issuance of warrants.

+ References

No definition available.

+ Details

Name:	sgoc_ChangeInFinancialLiabilitiesIssuanceOfWarrants
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- References

No definition available.

+ Details

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

X

- Definition

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

No definition available.

+ Details

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