Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2021	Sep. 30, 2020
Intangible Assets [Line Items]
Definite-lived intangible assets, Accumulated Amortization	$ (15,148)	$ (13,889)
Intangible assets, Gross Carrying Amount	27,176	27,172
Intangible assets, Net	$ 12,028	$ 13,283
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	$ 13,359	$ 13,356
Definite-lived intangible assets, Accumulated Amortization	(8,283)	(7,594)
Definite-lived intangible assets, Net	$ 5,076	$ 5,762
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	$ 9,686	$ 9,685
Definite-lived intangible assets, Accumulated Amortization	(4,659)	(4,200)
Definite-lived intangible assets, Net	$ 5,027	$ 5,485
Patents and Other [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	14 years 1 month 6 days	14 years 1 month 6 days
Definite-lived intangible assets, Gross Carrying Amount	$ 3,551	$ 3,551
Definite-lived intangible assets, Accumulated Amortization	(2,206)	(2,095)
Definite-lived intangible assets, Net	1,345	1,456
Definite-Lived Intangible Assets [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Gross Carrying Amount	26,596	26,592
Definite-lived intangible assets, Accumulated Amortization	(15,148)	(13,889)
Definite-lived intangible assets, Net	11,448	12,703
Trademarks and Trade Names [Member]
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Net	$ 580	$ 580