Leases - Additional Information (Details)		3 Months Ended		6 Months Ended
	Feb. 11, 2020 USD ($) MW	Apr. 30, 2020 USD ($)	Apr. 30, 2019 USD ($)	Apr. 30, 2020 USD ($)	Apr. 30, 2019 USD ($)	Nov. 01, 2019 USD ($)	Oct. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Operating lease ROU asset		$ 10,051,000		$ 10,051,000		$ 10,100,000
Operating lease liability		10,486,000		10,486,000		10,300,000
Adoption of new lease accounting standard, impact on accumulated deficit						0
Finance lease ROU assets		$ 100,000		$ 100,000
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:PropertyPlantAndEquipmentNet		us-gaap:PropertyPlantAndEquipmentNet
Finance lease, liability		$ 83,000		$ 83,000
Finance Lease, Liability, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesNoncurrent		us-gaap:OtherLiabilitiesNoncurrent
Operating lease expense		$ 100,000		$ 315,000	$ 0
Operating lease, weighted average remaining lease term		19 years		19 years
Operating lease, weighted average discount rate		6.20%		6.20%
Operating lease, payments		$ 200,000		$ 460,000	0
Long-term non-cancelable operating leases, Fiscal Year 2020							$ 1,100,000
Long-term non-cancelable operating leases, Fiscal Year 2021							1,400,000
Long-term non-cancelable operating leases, Fiscal Year 2022							1,300,000
Long-term non-cancelable operating leases, Fiscal Year 2023							900,000
Long-term non-cancelable operating leases, Fiscal Year 2024							700,000
Long-term non-cancelable operating leases, Thereafter							14,600,000
Long-term non-cancelable operating leases, rental commitments on an undiscounted lease payment							19,900,000
Sale leaseback transaction, net book value		$ 77,900,000		$ 77,900,000			$ 59,200,000
Crestmark Sale-Leaseback Transaction [Member]
Lessee Lease Description [Line Items]
Down payment and an initial rental payment under lease	$ 2,900,000
Initial term of lease	10 years
Monthly lease payments due	$ 100,000
Remaining lease payments due	9,300,000
Central CA Fuel Cell 2, LLC [Member] | Crestmark Sale-Leaseback Transaction [Member]
Lessee Lease Description [Line Items]
Sale leaseback transaction, net book value	14,400,000
Down payment and an initial rental payment under lease	2,900,000
Taxes and transaction costs	1,000,000.0
Net proceeds	10,500,000
Net proceeds deposited into project proceeds account	6,500,000
Net proceeds deposited into module reserve account and debt services reserve account	1,200,000
Quarterly cash interest due to lenders	$ 2,800,000
Purchase and Sale Agreement [Member] | Central CA Fuel Cell 2, LLC [Member] | Crestmark Sale-Leaseback Transaction [Member] | Tulare BioMAT [Member] | California [Member]
Lessee Lease Description [Line Items]
Capacity of plant | MW	2.8
ASC 842 [Member]
Lessee Lease Description [Line Items]
Operating lease ROU asset						10,100,000
Operating lease liability						$ 10,300,000
Operating lease expense			$ 200,000		$ 500,000
Minimum [Member]
Lessee Lease Description [Line Items]
Operating and finance lease, remaining lease term				1 year
Maximum [Member]
Lessee Lease Description [Line Items]
Operating and finance lease, remaining lease term				26 years