Nature of Business and Basis of Presentation - Additional Information (Details)			3 Months Ended				6 Months Ended	12 Months Ended	28 Months Ended
	May 01, 2024 USD ($) $ / shares shares	Apr. 10, 2024 USD ($) shares	Apr. 30, 2024 USD ($) shares	Jan. 31, 2024 MW	Oct. 31, 2023 USD ($) Plant MW	Apr. 30, 2023 USD ($) shares	Apr. 30, 2024 USD ($) $ / shares MW shares	Oct. 31, 2023 USD ($)	Oct. 31, 2024 shares
Nature of Business and Basis of Presentation
Cash and cash equivalents, unrestricted			$ 158,790,000		$ 249,952,000	$ 246,844,000	$ 158,790,000	$ 249,952,000
Investments - short-term			101,340,000		103,760,000		101,340,000	103,760,000
Proceeds from the issuance of debt							13,000,000
US Treasury Securities
Nature of Business and Basis of Presentation
Investments - short-term			101,300,000		$ 103,800,000		101,300,000	103,800,000
Derby Senior Back Leverage Loan Facility and Derby Subordinated Back Leverage Loan Facility
Nature of Business and Basis of Presentation
Debt instrument, face amount			$ 13,000,000.0				13,000,000.0
Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Closing costs								1,800,000
Number of Fuel Cell Power Plants, Tax Equity Financing Transaction | Plant					2
Tax Equity Financing Commitment					$ 30,200,000			30,200,000
Tax equity financing transaction, commitment amount received							$ 21,100,000	$ 9,100,000
Amended Open Market Sales Agreement | Subsequent Event
Nature of Business and Basis of Presentation
Shares sold during the period | shares	38,600,000
Average sale price per share | $ / shares	$ 0.84
Net proceeds from issuance of common stock	$ 31,700,000
Common stock issuance, net of fees	32,300,000
Payments of underwriting discounts and commissions	$ 600,000
Common Stock
Nature of Business and Basis of Presentation
Shares sold during the period | shares			6,463,716			949,438
Common Stock | Amended Open Market Sales Agreement | Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC
Nature of Business and Basis of Presentation
Shares sold during the period | shares		0					6,500,000		6,500,000
Aggregate offering price		$ 300.0
Gross proceeds from issuance of common stock							$ 6,300,000
Average sale price per share | $ / shares							$ 0.98
Net proceeds from issuance of common stock							$ 5,900,000
Common stock issuance, net of fees							5,900,000
Sales commission		$ 100,000					100,000
Payments of underwriting discounts and commissions							300,000
Offering price			$ 293,700,000				$ 293,700,000
Derby Project 14.0 Mega Watt
Nature of Business and Basis of Presentation
Capacity of plant | MW							14.0
Derby Project 14.0 Mega Watt | Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Capacity of plant | MW					14.0
Derby Project 2.8 Mega Watt
Nature of Business and Basis of Presentation
Capacity of plant | MW							2.8
Derby Project 2.8 Mega Watt | Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Capacity of plant | MW					2.8
Groton Project
Nature of Business and Basis of Presentation
Capacity of plant due to Technical Improvement Plan | MW				7.4
Contribution received under the Technical Improvement Plan							$ 4,000,000.0