Marketable Securities - Investments in Marketable Securities (Details) - USD ($) $ in Thousands	Feb. 03, 2018	Jan. 28, 2017
Financial Instruments And Marketable Securities [Line Items]
Cost or Amortized Cost	$ 82,685	$ 54,802
Gross Unrealized Holding Gains	65	121
Estimated Fair Value	82,750	54,923
Commercial Paper
Financial Instruments And Marketable Securities [Line Items]
Cost or Amortized Cost	59,566	44,785
Gross Unrealized Holding Gains	23	107
Estimated Fair Value	59,589	44,892
Fixed income securities
Financial Instruments And Marketable Securities [Line Items]
Cost or Amortized Cost	23,119	10,017
Gross Unrealized Holding Gains	42	14
Estimated Fair Value	$ 23,161	$ 10,031