Revenue Recognition - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	May 31, 2023 USD ($)	Apr. 30, 2024 USD ($) T	Apr. 30, 2023 USD ($)	Apr. 30, 2024 USD ($) T	Apr. 30, 2023 USD ($)	Oct. 31, 2023 USD ($)	Oct. 31, 2022 USD ($)	Mar. 31, 2024 USD ($)	Jan. 31, 2024 USD ($)
Revenue Recognition
Contract asset		$ 47,800		$ 47,800		$ 42,100
Contract asset, Long-term		21,400		21,400		25,800
Contract liability		7,700		7,700		3,100
Revenues		$ 22,420	$ 38,349	39,111	$ 75,422
Toyota Investment Tax Credit Sale
Revenue Recognition
Consideration payable						6,300
Consideration payable, Long term						6,000
Sale of investment tax credit						$ 6,300
Hydrogen production and power purchase agreement						20 years
EMTEC Joint Development Agreement
Revenue Recognition
Contract liability									$ 11,600
Revenues	$ 2,500			$ 900
Milestone payment received							$ 5,000
Remaining balance	$ 2,500
Discount on purchase of fuel cell module						$ 2,500
Milestone based payments							$ 5,000
Amendment No 5 to EMTEC Joint Development Agreement
Revenue Recognition
Minimum expected annual budget for the anticipated work through the remaining term of agreement								$ 10,000
Amendment No 5 to EMTEC Joint Development Agreement | Maximum
Revenue Recognition
CO2 capture annual basis | T		250,000		250,000
Product
Revenue Recognition
Revenues					9,095
Remaining performance obligations		$ 12,300		$ 12,300
Service
Revenue Recognition
Revenues		1,369	26,190	2,986	40,072
Generation
Revenue Recognition
Revenues		14,118	8,440	24,611	17,997
Remaining performance obligations		$ 335,300		$ 335,300
Generation | Maximum
Revenue Recognition
Revenue performance obligation expected timing of satisfaction		20 years		20 years
Generation | Minimum
Revenue Recognition
Revenue performance obligation expected timing of satisfaction		19 years		19 years
Advanced Technologies
Revenue Recognition
Revenues		$ 6,933	$ 3,719	$ 11,514	$ 8,258
Remaining performance obligations		$ 14,200		$ 14,200
Advanced Technologies | Maximum
Revenue Recognition
Revenue performance obligation expected timing of satisfaction		2 years		2 years
Service Agreements | Service
Revenue Recognition
Remaining performance obligations		$ 145,100		$ 145,100
Service Agreements | Service | Maximum
Revenue Recognition
Revenue performance obligation expected timing of satisfaction		15 years		15 years
Service Agreements | Service | Minimum
Revenue Recognition
Revenue performance obligation expected timing of satisfaction		3 years		3 years