Fair Value Measurements - Estimated Fair Value and Carrying Value of 2019, 2020 and 2023 Notes (Detail) - USD ($) $ in Thousands	May 04, 2019	Feb. 02, 2019
Convertible senior notes due 2019
Fair Value Balance Sheet Grouping Financial Statement Captions
Convertible senior notes, Fair Value	$ 347,211	$ 334,756
Convertible senior notes, Carrying Value	348,037	344,146
Convertible senior notes due 2020
Fair Value Balance Sheet Grouping Financial Statement Captions
Convertible senior notes, Fair Value	277,652	260,258
Convertible senior notes, Carrying Value	277,358	272,919
Convertible senior notes due 2023
Fair Value Balance Sheet Grouping Financial Statement Captions
Convertible senior notes, Fair Value	257,639	230,684
Convertible senior notes, Carrying Value	$ 257,736	$ 253,689

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_ConvertibleNotesPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant