Goodwill and Other Identifiable Intangible Assets, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 85,906	$ 75,694
Accumulated amortization	(73,377)	(71,653)
Net	12,529	4,041
Purchased and Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	51,017	46,594
Accumulated amortization	(45,757)	(44,999)
Net	5,260	1,595
License Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	144	18
Accumulated amortization	(15)	(10)
Net	129	8
Patents and Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	12,410	11,619
Accumulated amortization	(11,133)	(10,871)
Net	1,277	748
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	21,735	17,463
Accumulated amortization	(16,412)	(15,773)
Net	5,323	1,690
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	600	0
Accumulated amortization	(60)	0
Net	$ 540	$ 0