Quarterly report pursuant to Section 13 or 15(d)

Description of business and summary of significant accounting policies - Additional Information (Details)

v2.4.1.9
Description of business and summary of significant accounting policies - Additional Information (Details) (USD $)
3 Months Ended
Mar. 31, 2015
segment
Mar. 31, 2014
Dec. 31, 2014
Debt Instrument [Line Items]      
Number of Operating Segments 1us-gaap_NumberOfOperatingSegments    
Loss on Contracts $ 0us-gaap_LossOnContracts $ 217,000us-gaap_LossOnContracts  
Allowance for Doubtful Accounts Receivable, Current 50,000us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent    
Goodwill $ 40,870us-gaap_Goodwill   $ 40,870us-gaap_Goodwill
Ilios      
Debt Instrument [Line Items]      
Noncontrolling Interest, Ownership Percentage by Parent 65.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= tcgn_IliosMember
   
Restricted stock | Ilios      
Debt Instrument [Line Items]      
Noncontrolling Interest, Ownership Percentage by Parent 63.70%us-gaap_MinorityInterestOwnershipPercentageByParent
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IliosMember