Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Oct. 29, 2016	Oct. 31, 2015	Oct. 29, 2016	Oct. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 23,598	$ (11,610)	$ 77,721	$ 23,037
Other comprehensive income (loss):
Unrealized (losses) gains on marketable securities, net of taxes	(35)	12	4	(6)
Foreign currency translation (losses) gains, net of taxes	(19)	(31)	(46)	90
Comprehensive income (loss)	$ 23,544	$ (11,629)	$ 77,679	$ 23,121

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831270

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831223

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=51831255

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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