Segment Information - Property and Equipment Net on Geographical Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Property and equipment, net	$ 38,208	$ 36,677
United States
Segment Reporting Information [Line Items]
Property and equipment, net	29,949	29,276
International
Segment Reporting Information [Line Items]
Property and equipment, net	$ 8,259	$ 7,401
Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration of risk, percentage	100.00%	100.00%	100.00%
Geographic Concentration Risk | United States | Property Plant and Equipment
Segment Reporting Information [Line Items]
Concentration of risk, percentage	78.00%	80.00%
Geographic Concentration Risk | International | Property Plant and Equipment
Segment Reporting Information [Line Items]
Concentration of risk, percentage	22.00%	20.00%