Convertible Senior Notes - Carrying Value of Notes Excluding the Discounts and Commissions Payable to the Initial Purchasers and Third Party Offering Costs (Detail) - Convertible Senior Notes Due 2019 [Member] - USD ($) $ in Thousands	Jul. 29, 2017	Jan. 28, 2017	Jun. 30, 2014
Liability component
Principal	$ 350,000	$ 350,000
Less: Debt discount	(28,304)	(35,457)	$ (4,400)
Net carrying amount	321,696	314,543
Equity component	$ 70,482	$ 70,482