Fair Value of Financial Instruments - Estimated Fair Value and Carrying Value of 2019, 2020 and 2023 Notes (Detail) - USD ($) $ in Thousands	Nov. 03, 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	$ 336,113	$ 324,866
Convertible senior notes, Carrying Value	340,299	329,012
Convertible Senior Notes Due 2020 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Convertible senior notes, Fair Value	267,257	261,047
Convertible senior notes, Carrying Value	268,552	$ 255,865
Convertible Senior Notes Due 2023 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Convertible senior notes, Fair Value	242,642
Convertible senior notes, Carrying Value	$ 249,705