Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($) building	Sep. 30, 2019 USD ($) building	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	May 31, 2016
Loss Contingencies [Line Items]
Minimum lease payments due next twelve months	$ 1,000	$ 1,000
Minimum lease payments due in year two	800	800
Minimum lease payments due in year three	800	800
Minimum lease payments due in year four	900	900
Minimum lease payments due in year five	700	700
Minimum lease payments due thereafter	$ 1,400	1,400
Rent expense		$ 1,300	$ 1,200	$ 1,400
Risk-free rate, minimum (percentage)	1.20%	1.20%
Risk-free rate, maximum (percentage)	4.20%	4.20%
ARO period increase (decrease)		$ 100	100	(45)
Accretion expense		55	100	$ 100
ARO liability	$ 1,890	1,890	1,809
ARO terminated	40	40
Property in Alhambra, California
Loss Contingencies [Line Items]
ARO liability	1,900	$ 1,900	1,800
Period of effect driving ARO (years)		30 years
Property in Beijing, China
Loss Contingencies [Line Items]
Lease length in years					5 years
ARO liability	$ 100	$ 100	$ 100
Property Subject to Operating Lease | Building
Loss Contingencies [Line Items]
Number of buildings leased | building	6	6
Number of buildings with new leases signed | building	5	5
Lease length in years	3 years	3 years
Lease option length in years	3 years	3 years