Investments - Narrative (Details) - USD ($) $ in Thousands	Jan. 29, 2017	Jan. 31, 2016
Investment [Line Items]
Cash and cash equivalents	$ 1,425	$ 0
Total equity investment in privately traded companies	27,100	20,200
Other assets
Investment [Line Items]
Total equity investment in privately traded companies	21,000
Restricted deposit	5,000
Level 1 | Agency securities
Investment [Line Items]
Cash and cash equivalents	$ 16,945	$ 16,866