Segment Information - Property and Equipment Net on Geographical Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Property and equipment, net	$ 45,122	$ 38,208
United States
Segment Reporting Information [Line Items]
Property and equipment, net	36,083	29,949
International
Segment Reporting Information [Line Items]
Property and equipment, net	$ 9,039	$ 8,259
Product Concentration Risk | Sales Revenue
Segment Reporting Information [Line Items]
Concentration of risk, percentage	100.00%	100.00%	100.00%
Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration of risk, percentage	100.00%	100.00%	100.00%
Geographic Concentration Risk | United States | Sales Revenue
Segment Reporting Information [Line Items]
Concentration of risk, percentage	64.00%	60.00%	58.00%
Geographic Concentration Risk | United States | Property Plant and Equipment
Segment Reporting Information [Line Items]
Concentration of risk, percentage	80.00%	78.00%
Geographic Concentration Risk | International | Property Plant and Equipment
Segment Reporting Information [Line Items]
Concentration of risk, percentage	20.00%	22.00%
Applications | Product Concentration Risk | Sales Revenue
Segment Reporting Information [Line Items]
Concentration of risk, percentage	61.00%	63.00%	64.00%