|
Stock-based compensation - Stock Option Activity (Details) (USD $)
|
6 Months Ended | 12 Months Ended | 3 Months Ended | 6 Months Ended | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Jun. 30, 2014
|
Jun. 30, 2014
Tecogen
|
Dec. 31, 2013
Tecogen
|
Mar. 31, 2013
Ilois
|
Jun. 30, 2014
Ilois
|
Dec. 31, 2013
Ilois
|
Mar. 31, 2014
Minimum
Tecogen
|
Dec. 31, 2012
Minimum
Tecogen
|
Mar. 31, 2014
Minimum
Ilois
|
Dec. 31, 2012
Minimum
Ilois
|
Mar. 31, 2014
Maximum
Tecogen
|
Dec. 31, 2012
Maximum
Tecogen
|
Mar. 31, 2014
Maximum
Ilois
|
Dec. 31, 2012
Maximum
Ilois
|
|
| Stock Options Outstanding [Roll Forward] | ||||||||||||||
| Beginning (shares) | 1,148,000 | 575,000 | ||||||||||||
| Granted (shares) | 93,325 | 50,000 | ||||||||||||
| Exercised (shares) | (5,000) | 0 | ||||||||||||
| Canceled and forfeited (shares) | (3,200) | 0 | ||||||||||||
| Expired (shares) | 0 | 0 | ||||||||||||
| Ending (shares) | 1,233,125 | 1,148,000 | 625,000 | |||||||||||
| Exercisable (shares) | 926,125 | 181,250 | ||||||||||||
| Vested and expected to vest (shares) | 1,233,125 | 625,000 | ||||||||||||
| Exercise Price Per Share [Abstract] | ||||||||||||||
| Exercise Price Per Share, Beginning (per share) | $ 1.2 | $ 1.20 | $ 0.10 | $ 0.10 | $ 4.5 | $ 4.50 | $ 0.50 | $ 0.50 | ||||||
| Exercise Price Per Share, Granted (per share) | $ 4.50 | $ 0.50 | ||||||||||||
| Exercise Price Per Share, Exercised (per share) | $ 1.20 | $ 0 | ||||||||||||
| Exercise Price Per Share, Cancelled and forfeited (per share) | $ 0 | $ 1.20 | $ 4.50 | |||||||||||
| Exercise Price Per Share, Expired (per share) | $ 0.00 | $ 0 | ||||||||||||
| Exercise Price Per Share, Ending (per share) | $ 1.2 | $ 1.20 | $ 0.10 | $ 0.10 | $ 4.5 | $ 4.50 | $ 0.50 | $ 0.50 | ||||||
| Weighted Average Exercise Price [Roll Forward] | ||||||||||||||
| Beginning (usd per share) | $ 2.13 | $ 0.29 | ||||||||||||
| Granted (usd per share) | $ 4.50 | $ 0.50 | ||||||||||||
| Exercised (usd per share) | $ 1.20 | $ 0 | ||||||||||||
| Canceled and forfeited (usd per share) | $ 1.92 | $ 0 | ||||||||||||
| Expried (usd per share) | $ 0.00 | $ 0 | ||||||||||||
| Ending (usd per share) | $ 2.31 | $ 2.13 | $ 0.31 | |||||||||||
| Exercisable (usd per share) | $ 1.92 | $ 0.50 | ||||||||||||
| Vested and expected to vest (usd per share) | $ 2.31 | $ 0.31 | ||||||||||||
| Weighted Average Remaining Life | 5 years 8 months 2 days | 5 years 9 months 18 days | 6 years 5 months 9 days | 6 years 3 months 0 days | ||||||||||
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] | ||||||||||||||
| Outstanding, Aggregate Intrinsic Value | $ 6,999,956 | $ 2,721,100 | $ 120,000 | $ 120,000 | ||||||||||
| Exercisable, Aggregate Intrinsic Value | 5,623,189 | 0 | ||||||||||||
| Vested and expected to vest, Aggregate Intrinsic Value | $ 6,999,956 | $ 120,000 | ||||||||||||