Goodwill and Other Identifiable Intangible Assets, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 85,189	$ 75,694
Accumulated amortization	(72,025)	(71,653)
Net	13,164	4,041
Purchased and Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	50,720	46,594
Accumulated amortization	(45,079)	(44,999)
Net	5,641	1,595
License Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	18	18
Accumulated amortization	(12)	(10)
Net	6	8
Patents and Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	12,334	11,619
Accumulated amortization	(10,974)	(10,871)
Net	1,360	748
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	21,517	17,463
Accumulated amortization	(15,930)	(15,773)
Net	5,587	1,690
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	600	0
Accumulated amortization	(30)	0
Net	$ 570	$ 0