Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Computers, software, office equipment and furniture	$ 2,198	$ 2,182
Land	2,996	2,996
Research equipment	46,873	38,283
Leasehold improvements	42,017	42,017
Construction in progress	127,216	56,373
Property and equipment, gross	221,300	141,851
Less: Accumulated depreciation and amortization	(36,072)	(31,554)
Property and equipment, net	$ 185,228	$ 110,297

Computers, software, office equipment and furniture gross.

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Research equipment gross.

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- Definition

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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