Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2018 USD ($) building	Dec. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 building	May 31, 2016
Loss Contingencies [Line Items]
Rent expense	$ 300	$ 300
Risk-free rate, minimum	1.20%
Risk-free rate, maximum	4.20%
Accretion expense	$ 14	$ 17
Property in Alhambra, California
Loss Contingencies [Line Items]
ARO liability	1,800		$ 1,800
Property in Beijing, China
Loss Contingencies [Line Items]
Lease length in years					5 years
ARO liability	$ 100		$ 100
Property Subject to Operating Lease | Building
Loss Contingencies [Line Items]
Number of buildings leased | building	6
Number of buildings with new leases signed | building				4
Lease length in years				3 years
Lease option length in years				3 years