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 basis of presentation (Policies)
Notes Tables
Notes Details

Stock-Based Compensation - Stock Option Activity (Details)

v3.19.1

Stock-Based Compensation - Stock Option Activity (Details) - Tecogen - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Stock Options Outstanding [Roll Forward]
Beginning (shares)	1,292,589
Granted (shares)	28,000
Exercised (shares)	(10,000)
Canceled and forfeited (shares)	(700)
Ending (shares)	1,309,889
Exercisable (shares)	854,639
Vested and expected to vest (shares)	1,241,602
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Outstanding, Minimum (per share)	$ 0.79	$ 0.79
Exercise Price Per Share, Outstanding, Maximum (dollars per share)	10.33	$ 10.33
Exercise Price Per Share, Exercised (dollars per share)	1.20
Exercise Price, Canceled and Forfeited (dollars per share)	4.50
Weighted Average Exercise Price [Roll Forward]
Beginning (usd per share)	3.52
Granted (usd per share)	3.64
Exercised (usd per share)	1.20
Canceled and forfeited (usd per share)	4.50
Ending (usd per share)	3.54
Exercisable (usd per share)	3.47
Vested and expected to vest (usd per share)	$ 3.53
Weighted Average Remaining Life	5 years 9 months 22 days	5 years 11 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Outstanding, Aggregate Intrinsic Value	$ 948,892		$ 671,331
Exercisable, Aggregate Intrinsic Value	786,297
Vested and expected to vest, Aggregate Intrinsic Value	$ 924,502
Minimum
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Granted (dollars per share)	$ 3.62
Maximum
Exercise Price Per Share [Abstract]
Exercise Price Per Share, Granted (dollars per share)	$ 3.80

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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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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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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 current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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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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