v2.4.1.9
Warrant derivative liability (Warrant activity) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Mar. 31, 2008
Changes in warrant activity        
Change in fair value of warrant derivative liability $ 19us-gaap_GainLossOnDerivativeInstrumentsNetPretax $ (3)us-gaap_GainLossOnDerivativeInstrumentsNetPretax $ 75us-gaap_GainLossOnDerivativeInstrumentsNetPretax  
Public Warrants [Member]        
Changes in warrant activity        
Warrants outstanding 598,850us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_PublicWarrantsMember
    4,239,300us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_PublicWarrantsMember
Expired (598,850)sgoc_ClassOfWarrantOrRightExpired
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_PublicWarrantsMember
     
Warrants outstanding      598,850us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_PublicWarrantsMember
4,239,300us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_PublicWarrantsMember
Warrants fair value   12sgoc_WarrantsFairValue
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_PublicWarrantsMember
   
Unit Options [Member]        
Changes in warrant activity        
Warrants outstanding 280,000us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnitOptionsMember
[1]      
Expired (280,000)sgoc_ClassOfWarrantOrRightExpired
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnitOptionsMember
[1]      
Warrants outstanding    [1]   280,000us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnitOptionsMember
[1]  
Warrants fair value   6sgoc_WarrantsFairValue
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnitOptionsMember
   
Underwriter Warrants [Member]        
Changes in warrant activity        
Warrants outstanding 13,571us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnderwriterWarrantsMember
     
Expired         
Warrants outstanding 13,571us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnderwriterWarrantsMember
  13,571us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnderwriterWarrantsMember
 
Warrants fair value $ 2sgoc_WarrantsFairValue
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnderwriterWarrantsMember
$ 3sgoc_WarrantsFairValue
/ us-gaap_ClassOfWarrantOrRightAxis
= sgoc_UnderwriterWarrantsMember
   
[1] Each unit option included one ordinary share and one ordinary share warrant.