Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Restricted Stock Activity (Details)

v2.4.1.9
Stockholders' equity - Restricted Stock Activity (Details) (Restricted stock, USD $)
12 Months Ended
Dec. 31, 2014
Tecogen  
Unvested Restricted Stock [Roll Forward]  
Unvested, Beginning (shares) 361,570us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Granted (shares) 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Vested (shares) (205,720)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Forfeited (shares) 7,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Unvested, Ending (shares) 163,350us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Weighted Average Grant Date Fair Value [Roll Forward]  
Unvested, Beginning (usd per share) $ 1.31us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Granted (usd per share) $ 0.00us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Vested (usd per share) $ 1.36us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Forfeited (usd per share) $ 2.60us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Unvested, Ending (usd per share) $ 1.31us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Ilois  
Unvested Restricted Stock [Roll Forward]  
Unvested, Beginning (shares) 310,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Granted (shares) 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Vested (shares) 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Forfeited (shares) 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Unvested, Ending (shares) 310,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Weighted Average Grant Date Fair Value [Roll Forward]  
Unvested, Beginning (usd per share) $ 0.10us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Granted (usd per share) $ 0.00us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Vested (usd per share) $ 0.00us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Forfeited (usd per share) $ 0.00us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Unvested, Ending (usd per share) $ 0.10us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember