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)

v3.4.0.3

Stock-based compensation - Stock Option Activity (Details) - Tecogen - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Stock Options Outstanding [Roll Forward]
Beginning (shares)	1,268,200
Granted (shares)	5,000
Exercised (shares)	0
Canceled and forfeited (shares)	(150,000)
Expired (shares)	0
Ending (shares)	1,123,200	1,268,200
Exercisable (shares)	849,558
Vested and expected to vest (shares)	1,123,200
Weighted Average Exercise Price [Roll Forward]
Beginning (usd per share)	$ 3.06
Granted (usd per share)	3.93
Exercised (usd per share)	0.00
Canceled and forfeited (usd per share)	3.39
Expired (usd per share)	0.00
Ending (usd per share)	3.02	$ 3.06
Exercisable (usd per share)	2.50
Vested and expected to vest (usd per share)	$ 3.02
Weighted Average Remaining Life	5 years 5 months 15 days	6 years 5 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Outstanding, Aggregate Intrinsic Value	$ 1,300,361	$ 985,578
Exercisable, Aggregate Intrinsic Value	1,286,161
Vested and expected to vest, Aggregate Intrinsic Value	$ 1,300,361
Minimum
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Outstanding (per share)	$ 1.20	$ 1.20
Maximum
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Outstanding (per share)	$ 5.39	$ 5.39

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Share-based Compensation Arrangement by Share-based Payment Award, Options, Cancellations and Forfeitures in Period

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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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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Number of share options (or share units) exercised during the current period.

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