Basis of Presentation and Summary of Significant Accounting Policies - Recently Adopted Accounting Standards (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Feb. 01, 2016	Apr. 30, 2016	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effective income tax rate reconciliation, share-based compensation, excess tax benefit, amount	$ 10,500
Provision for income taxes			$ 1,887	$ 1,569	$ 1,337
Stock-based compensation expense			116,668	$ 58,225	$ 53,033
Accounting Standards Update 2016-09 | New accounting pronouncement early adoption effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provision for income taxes			$ (1,000)
Stock-based compensation expense		$ 864
Accounting Standards Update 2016-09 | New accounting pronouncement early adoption effect | Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption		$ 2,100