Summary of Significant Accounting Policies (Revenue by Product) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 23,850	$ 21,745	$ 49,332	$ 45,746
Concentration risk percentage	100.00%	100.00%
Navigation And Inertial Sensing [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 8,842	$ 4,094	19,109	6,553
Concentration risk percentage	37.00%	19.00%
Defense Optoelectronics [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 4,171	$ 2,779	7,608	4,460
Concentration risk percentage	18.00%	13.00%
CA TV Lasers And Transmitters [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 8,782	$ 10,762	18,165	25,534
Concentration risk percentage	37.00%	49.00%
Chips [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 1,035	$ 3,501	2,590	7,716
Concentration risk percentage	4.00%	16.00%
Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 1,020	$ 609	$ 1,860	$ 1,483
Concentration risk percentage	4.00%	3.00%
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			39.00%	14.00%
Product Concentration Risk | Revenue from Contract with Customer | Defense Optoelectronics [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage			15.00%	10.00%
Product Concentration Risk | Revenue from Contract with Customer | CA TV Lasers And Transmitters [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage			37.00%	56.00%
Product Concentration Risk | Revenue from Contract with Customer | Chips [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage			5.00%	17.00%
Product Concentration Risk | Revenue from Contract with Customer | Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Concentration risk percentage			4.00%	3.00%