Summary of Significant Accounting Policies (Revenue by Product) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 25,482	$ 24,001
Navigation And Inertial Sensing [Member]
Disaggregation of Revenue [Line Items]
Revenue	10,267	2,459
Defense Optoelectronics [Member]
Disaggregation of Revenue [Line Items]
Revenue	3,437	1,681
CA TV Lasers And Transmitters [Member]
Disaggregation of Revenue [Line Items]
Revenue	9,383	14,772
Chips [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,555	4,215
Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 840	$ 874
Product Concentration Risk | Revenue from Contract with Customer
Disaggregation of Revenue [Line Items]
Concentration risk percentage	100.00%	100.00%
Product Concentration Risk | Revenue from Contract with Customer | Navigation And Inertial Sensing [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	40.00%	10.00%
Product Concentration Risk | Revenue from Contract with Customer | Defense Optoelectronics [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	13.00%	7.00%
Product Concentration Risk | Revenue from Contract with Customer | CA TV Lasers And Transmitters [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	37.00%	62.00%
Product Concentration Risk | Revenue from Contract with Customer | Chips [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	6.00%	18.00%
Product Concentration Risk | Revenue from Contract with Customer | Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage	4.00%	3.00%