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Debt - Components of the Convertible Notes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 25, 2020	Jul. 31, 2021	Jul. 25, 2020	Jan. 30, 2021	Jan. 25, 2020	Sep. 15, 2015
Debt Instrument [Line Items]
Equity component of 0.75% senior convertible notes due 2021, net	$ 112,600,000		$ 112,600,000
Amortization of debt discount			1,329,000	$ 6,089,000
Estimate of Fair Value Measurement
Debt Instrument [Line Items]
Debt instrument, face amount	57,609,000		57,609,000		$ 60,886,000
Less: Debt discount and debt issuance costs	(375,000)		(375,000)		(1,854,000)
Convertible Debt	57,234,000		57,234,000		59,032,000
0.75% Convertible Senior Notes Due 2021
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	(337,000)		(337,000)		(1,665,000)
Debt issuance cost	(38,000)		(38,000)		(189,000)
Amortization of debt discount	700,000	$ 1,700,000	1,300,000	$ 6,100,000
Debt instrument, face amount	58,264,000		58,264,000		58,264,000	$ 460,000,000	$ 485,000,000
Convertible Debt	$ 57,889,000		$ 57,889,000		$ 56,410,000