Subsequent Events (Details)			1 Months Ended
	May 22, 2023 shares	May 19, 2023 USD ($) project	Apr. 30, 2024	Apr. 30, 2023 USD ($) position	Apr. 08, 2021 shares
2018 Omnibus Incentive Plan
Subsequent Events
Number of shares authorized | shares					12,333,333
State of Connecticut Loan | Third Amendment
Subsequent Events
Number of consecutive months maintain full time positions				24 months
Number of minimum full time positions required to be maintained | position				91
Number of minimum full time positions required to be maintained including additional employment positions | position				629
Additional credits to be earned				$ 2,000,000.0
Consecutive term for average number of employees			24 months	24 months
Principal payable number of employee under employee obligation target				$ 14,225.00
State of Connecticut Loan | Employment Obligation [Member] | Third Amendment
Subsequent Events
Number of minimum full time positions required to be maintained | position				538
Subsequent Event [Member]
Subsequent Events
Term to maintain debt service coverage ratio		6 months
Notional amount of hedge	100.00%
Interest rate	3.716%
Qurterly principal payment		$ 675,000
Granted | shares	0
Subsequent Event [Member] | First four years
Subsequent Events
Interest rate	6.366%
Subsequent Event [Member] | Thereafter
Subsequent Events
Interest rate	6.866%
Subsequent Event [Member] | Liberty Bank, Fifth Third Bank and Connecticut Green Bank
Subsequent Events
Repayments of debt		11,400,000
Subsequent Event [Member] | Liberty Bank and Fifth Third Bank
Subsequent Events
Funds released from restricted cash		11,200,000
Unrestricted cash		46,100,000
Subsequent Event [Member] | PNC Energy Capital, LLC
Subsequent Events
Funds released from restricted and unrestricted reserve account		$ 7,300,000
Subsequent Event [Member] | Minimum
Subsequent Events
Notional amount of hedge		75.00%
Subsequent Event [Member] | Maximum
Subsequent Events
Notional amount of hedge		105.00%
Subsequent Event [Member] | Maximum | 2018 Omnibus Incentive Plan
Subsequent Events
Additional number of shares authorized | shares	6,000,000
Number of shares authorized | shares	18,333,333
Shares to be issued on exercise of stock options | shares	1,833,333
Subsequent Event [Member] | Maximum | Employee Stock Purchase Plan
Subsequent Events
Additional number of shares authorized | shares	500,000
Number of shares authorized | shares	541,667
Number of shares that can be purchased by individual participant | shares	1,000
Subsequent Event [Member] | Project Financing Facility
Subsequent Events
Number of operating fuel cell generation projects | project		6
Number of leased projects ownership reacquired | project		3
Repayments of debt		$ 1,800,000
Payments of debt issuance costs		2,900,000
Net proceeds from debt		77,600,000
Payments for lease buyouts and sales taxes		15,000,000.0
Payments to fund capital expenditure reserve account		14,500,000
Proceeds from debt, distributed to company		34,900,000
Unrestricted cash		$ 46,100,000
Initial interest period		3 months
Principal amortization period		17 years
Debt service coverage ratio		1.30%
Debt instrument term		7 years
Capital Expenditure Reserve		$ 29,000,000.0
Future capital expenditures or long-term capital investments		29,000,000.0
Capital expenditure reserve funded out of debt		$ 14,500,000
Threshold annual operating expense budget as percent of base case model, approval from lenders		115.00%
Trailing period for debt service coverage ratio		12 months
Debt service coverage ratio, testing frequency		6 months
Subsequent Event [Member] | Project Financing Facility | Applicable interest period one
Subsequent Events
Interest period		1 month
Subsequent Event [Member] | Project Financing Facility | Applicable interest period two
Subsequent Events
Interest period		3 months
Subsequent Event [Member] | Project Financing Facility | Applicable interest period three
Subsequent Events
Interest period		6 months
Subsequent Event [Member] | Project Financing Facility | SOFR rate
Subsequent Events
Initial interest period		3 months
Subsequent Event [Member] | Project Financing Facility | SOFR rate | First four years
Subsequent Events
Interest rate, basis points		2.50%
Subsequent Event [Member] | Project Financing Facility | SOFR rate | Thereafter
Subsequent Events
Interest rate, basis points		3.00%
Subsequent Event [Member] | Project Financing Facility | Base rate | First four years
Subsequent Events
Interest rate, basis points		1.50%
Subsequent Event [Member] | Project Financing Facility | Base rate | Thereafter
Subsequent Events
Interest rate, basis points		2.00%
Subsequent Event [Member] | Project Financing Facility | Liberty Bank and Fifth Third Bank
Subsequent Events
Funds released from restricted cash		$ 11,200,000
Subsequent Event [Member] | Project Financing Facility | PNC Energy Capital, LLC
Subsequent Events
Number of leased projects ownership reacquired | project		3
Subsequent Event [Member] | Project Financing Facility | Bridgeport Fuel Cell Project [Member] | Liberty Bank, Fifth Third Bank and Connecticut Green Bank
Subsequent Events
Encumbrance amount		$ 11,400,000
Subsequent Event [Member] | Project Financing Facility | Pfizer Project | PNC Energy Capital, LLC | Sale-leaseback Arrangements with PNC
Subsequent Events
Lease buyout amount		15,700,000
Subsequent Event [Member] | Project Financing Facility | Riverside Regional Water Quality Control Plant Project | PNC Energy Capital, LLC | Sale-leaseback Arrangements with PNC
Subsequent Events
Lease buyout amount		3,700,000
Subsequent Event [Member] | Project Financing Facility | Santa Rita Jail Project | Sale-leaseback Arrangements with PNC
Subsequent Events
Lease buyout amount		$ 2,800,000
Subsequent Event [Member] | Project Financing Facility | LIPA Yaphank Solid Waste Management Project [Member]
Subsequent Events
Extension term of gas agreement		3 years
Period to exercise option to purchase member interest in tax equity partnership		6 months
Subsequent Event [Member] | Project Financing Facility | Minimum
Subsequent Events
Debt service coverage ratio		1.20%
Annual operating expense budget approval from lenders, lending percent		50.00%
Subsequent Event [Member] | Term loan
Subsequent Events
Debt Instrument, Face Amount		$ 80,500,000
Funds released from restricted and unrestricted reserve account		7,300,000
Gross proceeds from debt		80,500,000
Subsequent Event [Member] | Letter of credit
Subsequent Events
Line of credit facility, maximum borrowing capacity		$ 6,500,000