Summary of Significant Accounting Policies - Property and Equipment Table (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 4.3	$ 3.4
Less: accumulated depreciation	(1.9)	(1.7)
Property Plant And Equipment, Net	2.4	1.7
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	0.9	0.3
Property and Equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 3.4	$ 3.1

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 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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