Segment and Revenue Information - Schedule of Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Revenue	$ 32,650	$ 38,406	$ 74,886	$ 71,832
Gross profit	9,017	14,634	24,814	27,206
R&D expense	4,535	3,771	9,162	8,067
Operating (loss) income	(2,313)	4,583	185	7,090
Unallocated expense
Selling, general, and administrative	7,563	6,062	14,750	11,860
Severance	20	0	1,318	0
(Gain) loss on sale of assets	(788)	218	(601)	189
Interest expense, net	12	49	23	98
Foreign exchange (loss) gain	17	68	(25)	(169)
Total unallocated expense	6,824	6,397	15,465	11,978
(Loss) income before income tax benefit (expense)	(2,342)	4,466	187	7,161
Operating segments
Segment Reporting Information [Line Items]
Revenue	32,650	38,406	74,886	71,832
Operating (loss) income	4,482	10,863	15,652	19,139
Operating segments | Aerospace And Defense
Segment Reporting Information [Line Items]
Revenue	9,006	13,134	18,906	26,770
Gross profit	1,233	3,775	2,917	7,875
R&D expense	4,041	3,157	8,203	6,843
Operating (loss) income	(2,808)	618	(5,286)	1,032
Operating segments | Broadband
Segment Reporting Information [Line Items]
Revenue	23,644	25,272	55,980	45,062
Gross profit	7,784	10,859	21,897	19,331
R&D expense	494	614	959	1,224
Operating (loss) income	$ 7,290	$ 10,245	$ 20,938	$ 18,107