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Stockholders' equity - Stock-Based Compensation (Details) (USD $)
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12 Months Ended | 12 Months Ended | 12 Months Ended | 12 Months Ended | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2012
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Dec. 31, 2013
Tecogen
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Dec. 31, 2012
Tecogen
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Dec. 31, 2012
Tecogen
Exercise price $3.20 per share
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Dec. 31, 2013
Tecogen
Exercise price $3.20 per share
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Dec. 31, 2013
Tecogen
Exercise price $4.50 per share
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Dec. 31, 2013
Tecogen
Stock options
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Dec. 31, 2012
Tecogen
Stock options
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Dec. 31, 2013
Tecogen
Restricted stock
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Dec. 31, 2012
Tecogen
Restricted stock
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Dec. 31, 2011
Tecogen
Restricted stock
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Dec. 31, 2013
Tecogen
Restricted stock
Minimum
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Dec. 31, 2013
Tecogen
Restricted stock
Maximum
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Dec. 31, 2013
Tecogen
Amended Plan
Stock options
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Dec. 31, 2012
Tecogen
Amended Plan
Stock options
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Dec. 31, 2006
Tecogen
Amended Plan
Stock options
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Dec. 31, 2013
Ilois
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Dec. 31, 2012
Ilois
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Dec. 31, 2013
Ilois
Restricted stock
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Dec. 31, 2012
Ilois
Restricted stock
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Dec. 31, 2011
Ilois
Restricted stock
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Dec. 31, 2013
Ilois
Restricted stock
Minimum
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Dec. 31, 2013
Ilois
Restricted stock
Maximum
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Dec. 31, 2013
Ilois
2009 Plan
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||||||||||||||||||
| Shares of common stock reserved for future issuance | 1,838,750 | 1,000,000 | ||||||||||||||||||||||
| Number of shares remaining available for future issuance | 58,683 | 135,183 | ||||||||||||||||||||||
| Maximum number of shares allowable for issuance | 2,000,000 | |||||||||||||||||||||||
| Options granted | 76,500 | 17,500 | 17,500 | 37,500 | 39,000 | 0 | 50,000 | |||||||||||||||||
| Options granted, exercise price in usd per share | $ 3.20 | $ 3.20 | $ 3.20 | $ 4.50 | $ 0 | $ 0.50 | ||||||||||||||||||
| Fair value of options issued | $ 80,952 | $ 20,223 | $ 9,750 | |||||||||||||||||||||
| Weighted-average grant date fair value of options granted | $ 1.16 | $ 0.75 | $ 1.35 | $ 0.20 | ||||||||||||||||||||
| Options repurchased from consultant, charge to Stockholders' Equity | 337 | |||||||||||||||||||||||
| Restricted stock granted | 0 | 0 | 0 | 0 | ||||||||||||||||||||
| Award vesting period | 5 years | 4 years | 4 years | 90 days | 1 year | 4 years | 90 days | 1 year | ||||||||||||||||
| Vesting percentage | 100.00% | 100.00% | 100.00% | 100.00% | ||||||||||||||||||||
| Award expiration period | 10 years | 10 years | 10 years | |||||||||||||||||||||
| Recognized stock-based compensation | 136,184 | (41,311) | 59,361 | |||||||||||||||||||||
| Unvested restricted stock outstanding | 361,570 | 399,070 | 483,317 | 310,000 | 510,000 | 560,000 | ||||||||||||||||||
| Compensation cost related to unvested restricted stock awards and stock option awards not yet recognized | $ 124,845 | $ 183,230 | $ 9,004 | $ 67,493 | ||||||||||||||||||||
| Compensation cost not yet recognized, weighted average period of recognition | 0 years 6 months 22 days | 1 year 7 months 1 day | ||||||||||||||||||||||