Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Stock-Based Compensation (Details)

v2.4.1.9
Stockholders' equity - Stock-Based Compensation (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Tecogen    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 318,325us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
 
Fair value of options issued $ 577,029us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
$ 80,952us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Recognized stock-based compensation 117,138us-gaap_AllocatedShareBasedCompensationExpense
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
59,678us-gaap_AllocatedShareBasedCompensationExpense
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Compensation cost related to unvested restricted stock awards and stock option awards not yet recognized 156,179us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
124,845us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Compensation cost not yet recognized, weighted average period of recognition 0 years 6 months 22 days  
Tecogen | Exercise price $3.20 per share    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted   37,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceOneMember
Options granted, exercise price in usd per share   $ 3.20tcgn_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansGrantedExercisePrice
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceOneMember
Weighted-average grant date fair value of options granted   $ 0.75us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceOneMember
Tecogen | Exercise price $3.20 per share    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 318,325us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceThreeMember
 
Options granted, exercise price in usd per share $ 4.50tcgn_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansGrantedExercisePrice
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceThreeMember
 
Weighted-average grant date fair value of options granted $ 1.89us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceThreeMember
 
Tecogen | Exercise price $4.50 per share    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted   39,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceTwoMember
Options granted, exercise price in usd per share $ 5.39tcgn_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansGrantedExercisePrice
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceTwoMember
$ 4.50tcgn_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansGrantedExercisePrice
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceTwoMember
Weighted-average grant date fair value of options granted   $ 1.35us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= tcgn_ExercisePriceTwoMember
Tecogen | Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 4 years 4 years
Award expiration period 10 years 10 years
Tecogen | Restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unvested restricted stock outstanding 163,350us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
361,570us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Tecogen | Restricted stock | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 90 days  
Vesting percentage 100.00%tcgn_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
 
Tecogen | Restricted stock | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 1 year  
Vesting percentage 100.00%tcgn_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Tecogen | Performance Shares    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 100,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
 
Award vesting period 1 year  
Tecogen | Amended Plan | Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares of common stock reserved for future issuance 3,838,750us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_PlanNameAxis
= tcgn_AmendnedStockOptionAndIncentivePlan2006Member
 
Number of shares remaining available for future issuance 1,748,783us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_PlanNameAxis
= tcgn_AmendnedStockOptionAndIncentivePlan2006Member
58,683us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_PlanNameAxis
= tcgn_AmendnedStockOptionAndIncentivePlan2006Member
Ilois    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 100,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ dei_LegalEntityAxis
= tcgn_IloisMember
 
Options granted, exercise price in usd per share $ 0.50tcgn_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansGrantedExercisePrice
/ dei_LegalEntityAxis
= tcgn_IloisMember
 
Recognized stock-based compensation 9,798us-gaap_AllocatedShareBasedCompensationExpense
/ dei_LegalEntityAxis
= tcgn_IloisMember
(41,311)us-gaap_AllocatedShareBasedCompensationExpense
/ dei_LegalEntityAxis
= tcgn_IloisMember
Compensation cost related to unvested restricted stock awards and stock option awards not yet recognized $ 14,478us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ dei_LegalEntityAxis
= tcgn_IloisMember
$ 9,004us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ dei_LegalEntityAxis
= tcgn_IloisMember
Compensation cost not yet recognized, weighted average period of recognition 1 year 2 months 25 days  
Ilois | Restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unvested restricted stock outstanding 310,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
310,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
Ilois | Restricted stock | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 90 days  
Vesting percentage 100.00%tcgn_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
 
Ilois | Restricted stock | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 1 year  
Vesting percentage 100.00%tcgn_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ dei_LegalEntityAxis
= tcgn_IloisMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Ilois | 2009 Plan    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum number of shares allowable for issuance 2,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ dei_LegalEntityAxis
= tcgn_IloisMember
/ us-gaap_PlanNameAxis
= tcgn_StockIncentivePlan2009Member