Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2020	Sep. 30, 2019
Intangible Assets [Line Items]
Definite-lived intangible assets, Accumulated Amortization	$ (17,064)	$ (15,769)
Intangible assets, Gross Carrying Amount	30,101	29,995
Intangible assets, Net	$ 13,037	$ 14,226
Customer Lists and Relationships [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	8 years 10 months 24 days	8 years 10 months 24 days
Definite-lived intangible assets, Gross Carrying Amount	$ 17,460	$ 17,374
Definite-lived intangible assets, Accumulated Amortization	(11,404)	(10,661)
Definite-lived intangible assets, Net	$ 6,056	$ 6,713
Developed Technology [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	11 years 6 months	11 years 6 months
Definite-lived intangible assets, Gross Carrying Amount	$ 9,510	$ 9,490
Definite-lived intangible assets, Accumulated Amortization	(3,650)	(3,196)
Definite-lived intangible assets, Net	$ 5,860	$ 6,294
Non-compete [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	5 years	5 years
Definite-lived intangible assets, Gross Carrying Amount	$ 230	$ 230
Definite-lived intangible assets, Accumulated Amortization	(219)	(196)
Definite-lived intangible assets, Net	$ 11	$ 34
Patents and Other [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	16 years 6 months	16 years 6 months
Definite-lived intangible assets, Gross Carrying Amount	$ 2,321	$ 2,321
Definite-lived intangible assets, Accumulated Amortization	(1,791)	(1,716)
Definite-lived intangible assets, Net	530	605
Definite-Lived Intangible Assets [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Gross Carrying Amount	29,521	29,415
Definite-lived intangible assets, Accumulated Amortization	(17,064)	(15,769)
Definite-lived intangible assets, Net	12,457	13,646
Trademarks and Trade Names [Member]
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Net	$ 580	$ 580