Quarterly report pursuant to Section 13 or 15(d)

Cover
- Document and Entity Information Document and Entity Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- Description of business and summary of significant accounting policies (Policies)
Notes Tables
Notes Details

Stock-based compensation - Stock Option Activity (Details)

v2.4.1.9

Stock-based compensation - Stock Option Activity (Details) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2012	Dec. 31, 2014
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Expired (per share)	$ 0.00
Tecogen
Stock Options Outstanding [Roll Forward]
Beginning (shares)	1,356,325
Granted (shares)	0
Exercised (shares)	(222,375)
Canceled and forfeited (shares)	(13,150)
Expired (shares)	0
Ending (shares)	1,120,800
Exercisable (shares)	759,144
Vested and expected to vest (shares)	1,120,800
Weighted Average Exercise Price [Roll Forward]
Beginning (usd per share)	$ 2.77
Granted (usd per share)	$ 0.00
Exercised (usd per share)	$ 1.62
Canceled and forfeited (usd per share)	$ 3.15
Expried (usd per share)	$ 0.00
Ending (usd per share)	$ 2.99
Exercisable (usd per share)	$ 2.21
Vested and expected to vest (usd per share)	$ 2.99
Weighted Average Remaining Life	6 years 2 months 13 days	5 years 1 month 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Outstanding, Aggregate Intrinsic Value	$ 2,330,359				$ 3,618,935
Exercisable, Aggregate Intrinsic Value	2,171,496
Vested and expected to vest, Aggregate Intrinsic Value	$ 2,330,359
Minimum \| Tecogen
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Beginning (per share)			$ 1.2	$ 1.20
Exercise Price Per Share, Granted (per share)	$ 1.20
Exercise Price Per Share, Cancelled and forfeited (per share)				$ 2.6
Exercise Price Per Share, Ending (per share)			$ 1.2	$ 1.20
Maximum \| Tecogen
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Beginning (per share)			$ 5.39	$ 5.39
Exercise Price Per Share, Granted (per share)	$ 2.60
Exercise Price Per Share, Cancelled and forfeited (per share)				$ 4.50
Exercise Price Per Share, Ending (per share)			$ 5.39	$ 5.39

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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