Fair Value of Financial Instruments - Estimated Fair Value and Carrying Value of 2019, 2020 and 2023 Notes (Detail) - USD ($) $ in Thousands	Aug. 04, 2018	Feb. 03, 2018
Convertible Senior Notes Due 2019 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Convertible senior notes, Fair Value	$ 332,232	$ 324,866
Convertible senior notes, Carrying Value	336,494	329,012
Convertible Senior Notes Due 2020 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Convertible senior notes, Fair Value	265,796	261,047
Convertible senior notes, Carrying Value	264,255	$ 255,865
Convertible Senior Notes Due 2023 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Convertible senior notes, Fair Value	245,275
Convertible senior notes, Carrying Value	$ 245,783