Investments - Narrative (Details) - USD ($) $ in Thousands	Jan. 28, 2018	Jan. 29, 2017
Investment [Line Items]
Cash equivalents	$ 1,960	$ 1,425
Total equity investment in privately traded companies	38,100	27,100
Other assets
Investment [Line Items]
Total equity investment in privately traded companies	28,000
Restricted deposit	5,000
Level 1 | Cash equivalents
Investment [Line Items]
Cash equivalents	0	16,945
Convertible debt
Investment [Line Items]
Cash equivalents	$ 1,960	$ 1,425