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Subsequent events (Details) (USD $)
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12 Months Ended | 0 Months Ended | 0 Months Ended | 12 Months Ended | 3 Months Ended | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2013
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Dec. 31, 2012
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Feb. 25, 2014
Subsequent event
employee
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Jan. 02, 2014
Subsequent event
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Mar. 26, 2014
Chief Executive Officer (John N. Hatsopoulos)
Subsequent event
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Dec. 31, 2012
Demand notes
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Jan. 06, 2014
Demand notes
Subsequent event
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Dec. 31, 2013
Demand notes
Chief Executive Officer (John N. Hatsopoulos)
|
Dec. 31, 2012
Demand notes
Chief Executive Officer (John N. Hatsopoulos)
|
Jan. 06, 2014
Revolving credit facility
Subsequent event
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Dec. 31, 2013
Revolving credit facility
Chief Executive Officer (John N. Hatsopoulos)
|
Jul. 22, 2013
Revolving credit facility
Chief Executive Officer (John N. Hatsopoulos)
|
Mar. 25, 2013
Revolving credit facility
Chief Executive Officer (John N. Hatsopoulos)
|
Jan. 06, 2014
Revolving credit facility
Chief Executive Officer (John N. Hatsopoulos)
Subsequent event
|
Dec. 31, 2013
Common stock
|
Dec. 31, 2012
Common stock
|
Mar. 17, 2014
Common stock
Subsequent event
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| Subsequent Event [Line Items] | |||||||||||||||||
| Certificate of deposit securing letter of credit | $ 583,073 | ||||||||||||||||
| Senior convertible promissory note, related party | 3,000,000 | 0 | 1,337,500 | 1,750,000 | 1,750,000 | 1,300,000 | |||||||||||
| Interest paid on debt | 55,639 | 0 | 175,311 | 25,347 | |||||||||||||
| Amount outstanding | 1,200,000 | 1,200,000 | |||||||||||||||
| Shares of common stock issued in private placements | 1,476,789 | 212,500 | 1,400 | ||||||||||||||
| Private placements, price in usd per share | $ 4.50 | $ 4.50 | |||||||||||||||
| Stock Issued During Period, Value, New Issues | 6,300 | ||||||||||||||||
| Number of service employees covered under Collective Bargaining Agreement | 3 | ||||||||||||||||
| Working capital line of credit with related party | $ 3,500,000 | $ 1,055,000 | $ 1,500,000 | ||||||||||||||