Commitments and Contingencies (Narrative) (Details)	12 Months Ended
	Sep. 30, 2020 USD ($) building	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Loss Contingencies [Line Items]
Minimum lease payments due next twelve months	$ 1,792,000
Minimum lease payments due in year two	1,806,000
Minimum lease payments due in year three	1,857,000
Minimum lease payments due in year four	1,686,000
Minimum lease payments due in year five	1,730,000
Minimum lease payments due thereafter	12,366,000
Rent expense	$ 1,900,000	$ 1,300,000	$ 1,200,000
Risk-free rate, minimum	1.20%
Risk-free rate, maximum	4.20%
Accretion expense	$ 32,000	100,000	$ 100,000
Lease option length in years	5 years
ARO liability	$ 2,022,000	1,890,000
Property in Alhambra, California
Loss Contingencies [Line Items]
ARO liability	$ 1,900,000	$ 1,800,000
Period of effect driving ARO (years)	30 years
Building
Loss Contingencies [Line Items]
Number of buildings leased | building	5
Number of buildings with new leases signed | building	5
Lease length in years	3 years
Lease option length in years	3 years