Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (213,752)	$ (183,231)	$ (78,561)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	32,254	15,392	4,431
Stock-based compensation expense	58,225	25,399	8,298
Contribution of common stock to the Pure Good Foundation	11,900	0	0
Other	(1,093)	277	92
Changes in operating assets and liabilities:
Accounts receivable, net	(67,292)	(44,197)	(12,038)
Inventory	1,481	(13,713)	(5,077)
Deferred commissions	(13,021)	(9,838)	(7,129)
Prepaid expenses and other assets	(8,704)	(6,550)	(4,400)
Accounts payable	24,901	3,474	5,243
Accrued compensation and other liabilities	24,710	12,450	6,771
Deferred revenue	142,535	56,842	15,141
Net cash used in operating activities	(7,856)	(143,695)	(67,229)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(39,355)	(42,227)	(12,273)
Purchases of intangible assets	0	(9,125)	0
Increase in restricted cash	(2,485)	(1,613)	(3,034)
Net cash used in investing activities	(41,840)	(52,965)	(15,307)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from initial public offering, net of issuance costs	459,425	0	0
Proceeds from issuance of convertible preferred stock, net of issuance costs	0	280,970	167,833
Net proceeds from exercise of stock options, including proceeds from repayment of promissory notes	6,008	7,665	2,670
Repurchase of common stock in connection with tender offers	0	(30,120)	(7,202)
Payments of deferred offering costs	(3,702)	(33)	0
Net cash provided by financing activities	461,731	258,482	163,301
Net increase in cash and cash equivalents	412,035	61,822	80,765
Cash and cash equivalents, beginning of period	192,707	130,885	50,120
Cash and cash equivalents, end of period	604,742	192,707	130,885
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for income taxes	1,118	429	87
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION
Conversion of convertible preferred stock to common stock upon initial public offering	543,940	0	0
Property and equipment purchased but not yet paid	6,212	1,323	1,224
Vesting of early exercised stock options and restricted stock awards	1,725	1,162	192
Cashless exercise of stock options during tender offers	0	2,057	640
Unpaid deferred offering costs	$ 546	$ 55	$ 0