Fair Value Measurements (Schedule of Financial Instruments Measure at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	Aug. 01, 2020	Feb. 01, 2020	Aug. 03, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market mutual funds	$ 69,963	$ 48,080	$ 15,684
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market mutual funds	69,963	48,080	15,684
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market mutual funds	0	0	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market mutual funds	$ 0	$ 0	$ 0