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Investments - Summary of Maturities of Available-for-sale Securities (Details) - USD ($)
$ in Thousands
Jul. 29, 2018
Jan. 28, 2018
Investment [Line Items]    
Available-for-sale securities, market value $ 2,605 $ 1,960
Available-for-sale securities, adjusted cost 2,605 1,960
Within 1 Year [Member]    
Investment [Line Items]    
Available-for-sale securities, market value 2,000 1,960
Available-for-sale securities, adjusted cost 2,000 1,960
After 1 Year Through 5 Years [Member]    
Investment [Line Items]    
Available-for-sale securities, market value 605 0
Available-for-sale securities, adjusted cost $ 605 $ 0