Fair Value Measurements - Financial Assets Categorized Based on Priority of Inputs to Valuation Technique Instruments (Details) - USD ($) $ in Thousands	Feb. 03, 2018	Jan. 28, 2017
Fair Value, Inputs, Level 1 | Cash Equivalents | Money Market Instruments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash equivalents	$ 46,441	$ 76,177
Fair Value, Inputs, Level 1 | Marketable Securities | Commercial Paper
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Marketable securities	0	0
Fair Value, Inputs, Level 1 | Marketable Securities | Fixed income securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Marketable securities	0	0
Fair Value, Inputs, Level 2 | Cash Equivalents | Money Market Instruments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash equivalents	0	0
Fair Value, Inputs, Level 2 | Marketable Securities | Commercial Paper
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Marketable securities	59,589	44,892
Fair Value, Inputs, Level 2 | Marketable Securities | Fixed income securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Marketable securities	23,161	10,031
Fair Value, Inputs, Level 3 | Cash Equivalents | Money Market Instruments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash equivalents	0	0
Fair Value, Inputs, Level 3 | Marketable Securities | Commercial Paper
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Marketable securities	0	0
Fair Value, Inputs, Level 3 | Marketable Securities | Fixed income securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Marketable securities	$ 0	$ 0