Long-Term Debt	9 Months Ended
Sep. 30, 2016
Debt Disclosure [Abstract]
Long-Term Debt	8. Long-Term Debt During the nine months ended September 30, 2016, Plug Power Inc. and its subsidiaries Emerging Power Inc. and Emergent Power Inc. entered into a Loan and Security Agreement with Hercules Capital, Inc. (Hercules) pursuant to which Hercules agreed to make available to the Company a secured term loan facility in the amount of up to $40.0 million (the Term Loan Facility), subject to certain terms and conditions. The Company borrowed $25.0 million under the Loan and Security Agreement on the date of closing, and incurred transaction costs of $1.1 million. The Company may borrow an additional $5.0 million under the Loan and Security Agreement between October 12, 2016 and December 12, 2016 subject to the Company satisfying certain conditions. The Company may also borrow an additional $10.0 million under the Loan and Security Agreement after June 27, 2016 and until June 27, 2017 subject to satisfying certain other conditions. Advances under the Term Loan Facility bear interest at the rate of 10.45% per annum, subject to compliance with financial covenants and other conditions. The Loan and Security Agreement includes covenants, limitations, and events of default customary for similar facilities. The term of the Loan and Security Agreement is three years, ending June 27, 2019 (the Maturity Date). Interest is payable on a monthly basis and the entire then outstanding principal balance of the Term Loan Facility, together with all accrued and unpaid interest, is due and payable on the Maturity Date. On the earliest to occur of the Maturity Date, the date on which the obligations under the Loan and Security Agreement are paid and the date on which such obligations become due and payable, the Company is also required to pay the Lender an end of term charge of 8.25%, based on the total amount of the Term Loan Facility. Until such time as certain net income milestones are met, the Loan and Security Agreement has financial covenants that require the Company to maintain at all times minimum unencumbered cash and cash equivalents equal to or greater than 75% of the then outstanding principal balance of the Term Loan Facility plus accounts payable aged more than 150 days. After such net income milestones are met, the Loan and Security Agreement’s financial covenants are reduced to require minimum unencumbered cash and cash equivalents equal to or greater than 50% of the then outstanding principal balance of the Term Loan Facility plus accounts payable aged more than 150 days. All obligations under the Loan and Security Agreement are unconditionally guaranteed by the Company’s subsidiaries, Emerging Power Inc. and Emergent Power Inc. The Term Loan Facility is secured by substantially all of Plug Power Inc. and the guarantors’ assets, including all intellectual property, all securities in domestic subsidiaries and 65% of the securities in foreign subsidiaries, subject to certain exceptions and exclusions. The Loan and Security Agreement contains customary covenants for arrangements of this type and other covenants agreed to by the parties, including, among others, (i) the provision of annual and quarterly financial statements, management rights and insurance policies and (ii) restrictions on incurring debt, granting liens, making acquisitions, making loans, paying dividends, dissolving, and entering into leases and asset sales. The Loan and Security Agreement also provides for customary events of default, including, among others, payment, bankruptcy, covenant, representation and warranty, change of control, judgment and material adverse effect defaults. The fair value of the Term Loan Facility approximates the carrying value of $23.5 million as of September 30, 2016.

8. Long-Term Debt

During the nine months ended September 30, 2016, Plug Power Inc. and its subsidiaries Emerging Power Inc. and Emergent Power Inc. entered into a Loan and Security Agreement with Hercules Capital, Inc. (Hercules) pursuant to which Hercules agreed to make available to the Company a secured term loan facility in the amount of up to $40.0 million (the Term Loan Facility), subject to certain terms and conditions. The Company borrowed $25.0 million under the Loan and Security Agreement on the date of closing, and incurred transaction costs of $1.1 million. The Company may borrow an additional $5.0 million under the Loan and Security Agreement between October 12, 2016 and December 12, 2016 subject to the Company satisfying certain conditions. The Company may also borrow an additional $10.0 million under the Loan and Security Agreement after June 27, 2016 and until June 27, 2017 subject to satisfying certain other conditions.

Advances under the Term Loan Facility bear interest at the rate of 10.45% per annum, subject to compliance with financial covenants and other conditions. The Loan and Security Agreement includes covenants, limitations, and events of default customary for similar facilities. The term of the Loan and Security Agreement is three years, ending June 27, 2019 (the Maturity Date).

Interest is payable on a monthly basis and the entire then outstanding principal balance of the Term Loan Facility, together with all accrued and unpaid interest, is due and payable on the Maturity Date. On the earliest to occur of the Maturity Date, the date on which the obligations under the Loan and Security Agreement are paid and the date on which such obligations become due and payable, the Company is also required to pay the Lender an end of term charge of 8.25%, based on the total amount of the Term Loan Facility.

Until such time as certain net income milestones are met, the Loan and Security Agreement has financial covenants that require the Company to maintain at all times minimum unencumbered cash and cash equivalents equal to or greater than 75% of the then outstanding principal balance of the Term Loan Facility plus accounts payable aged more than 150 days. After such net income milestones are met, the Loan and Security Agreement’s financial covenants are reduced to require minimum unencumbered cash and cash equivalents equal to or greater than 50% of the then outstanding principal balance of the Term Loan Facility plus accounts payable aged more than 150 days.

All obligations under the Loan and Security Agreement are unconditionally guaranteed by the Company’s subsidiaries, Emerging Power Inc. and Emergent Power Inc. The Term Loan Facility is secured by substantially all of Plug Power Inc. and the guarantors’ assets, including all intellectual property, all securities in domestic subsidiaries and 65% of the securities in foreign subsidiaries, subject to certain exceptions and exclusions.

The Loan and Security Agreement contains customary covenants for arrangements of this type and other covenants agreed to by the parties, including, among others, (i) the provision of annual and quarterly financial statements, management rights and insurance policies and (ii) restrictions on incurring debt, granting liens, making acquisitions, making loans, paying dividends, dissolving, and entering into leases and asset sales. The Loan and Security Agreement also provides for customary events of default, including, among others, payment, bankruptcy, covenant, representation and warranty, change of control, judgment and material adverse effect defaults.

The fair value of the Term Loan Facility approximates the carrying value of $23.5 million as of September 30, 2016.