Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019 USD ($) building	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) building	Jun. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	May 31, 2016
Loss Contingencies [Line Items]
Rent expense	$ 300	$ 300	$ 1,000	$ 900
Risk-free rate, minimum	1.20%		1.20%
Risk-free rate, maximum	4.20%		4.20%
Accretion expense	$ 14	$ 17	$ 41	$ 100
ARO terminated	40		40
Property in Alhambra, California
Loss Contingencies [Line Items]
ARO liability	1,800		$ 1,800		$ 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