Intangible Assets - Schedule of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Mar. 31, 2015	Sep. 30, 2014
Intangible Assets [Line Items]
Definite-lived intangible assets, Gross Carrying Amount	$ 8,223	$ 8,223
Definite-lived intangible assets, Accumulated Amortization	(5,649)	(5,277)
Definite-lived intangible assets, Net	2,574	2,946
Customer Lists [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	9 years	9 years
Definite-lived intangible assets, Gross Carrying Amount	4,857	4,857
Definite-lived intangible assets, Accumulated Amortization	(4,083)	(3,813)
Definite-lived intangible assets, Net	774	1,044
Core Technology [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	8 years	8 years
Definite-lived intangible assets, Gross Carrying Amount	530	530
Definite-lived intangible assets, Accumulated Amortization	(508)	(475)
Definite-lived intangible assets, Net	22	55
Patents and Other [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Weighted Average Original Life (Years)	16 years 9 months 18 days	16 years 9 months 18 days
Definite-lived intangible assets, Gross Carrying Amount	2,256	2,256
Definite-lived intangible assets, Accumulated Amortization	(1,058)	(989)
Definite-lived intangible assets, Net	1,198	1,267
Definite-Lived Intangible Assets [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Gross Carrying Amount	7,643	7,643
Definite-lived intangible assets, Accumulated Amortization	(5,649)	(5,277)
Definite-lived intangible assets, Net	1,994	2,366
Trademarks [Member]
Intangible Assets [Line Items]
Definite-lived intangible assets, Gross Carrying Amount	580	580
Definite-lived intangible assets, Net	$ 580	$ 580