Segment and Revenue Information - Schedule of Revenue by Major Product Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 124,126	$ 158,444
Inertial Navigation | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Revenue	45,318	36,539
Defense Optoelectronics | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Revenue	7,988	14,299
CATV Optical Transmitters and Components | Broadband
Disaggregation of Revenue [Line Items]
Revenue	58,488	95,255
Data Center Chips | Broadband
Disaggregation of Revenue [Line Items]
Revenue	4,814	3,106
Optical Sensing | Broadband
Disaggregation of Revenue [Line Items]
Revenue	$ 7,518	$ 9,245