Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) building	Mar. 31, 2018 USD ($)	Mar. 31, 2019 USD ($) building	Mar. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	May 31, 2016
Loss Contingencies [Line Items]
Rent expense	$ 300	$ 300	$ 600	$ 600
Risk-free rate, minimum	1.20%		1.20%
Risk-free rate, maximum	4.20%		4.20%
Accretion expense	$ 13	16	$ 27	$ 33
ARO terminated	40		40
Gain from change in estimate on ARO obligation	40	$ 0	40		$ 0
Property in Alhambra, California
Loss Contingencies [Line Items]
ARO liability	1,800		1,800		1,800
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