Acquisition - Summary of Purchase Price Allocation of Acquired Assets and Assumed Liabilities Based on Estimated Fair Values (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Apr. 03, 2015	Jun. 06, 2014
Business Acquisition [Line Items]
Goodwill	$ 117,375	$ 117,241
NetNearU [Member]
Business Acquisition [Line Items]
Current assets			$ 8,482
Property and equipment			1,087
Identifiable intangible assets			24,310
Goodwill			34,576
Total assets acquired			68,455
Current liabilities			(5,305)
Other long-term liabilities			(2,981)
Total liabilities assumed			(8,286)
Total purchase price			$ 60,169