Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (123,338)	$ (112,957)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	22,336	14,268
Stock-based compensation expense	50,894	20,659
Other	494	0
Changes in operating assets and liabilities:
Accounts receivable, net	6,589	(21,017)
Inventory	(2,392)	(1,653)
Deferred commissions	1,887	(4,865)
Prepaid expenses and other assets	(809)	(2,634)
Accounts payable	(10,007)	2,417
Accrued compensation and other liabilities	8,687	11,479
Deferred revenue	41,102	49,813
Net cash used in operating activities	(4,557)	(44,490)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(46,118)	(21,823)
Purchase of intangible assets	(1,000)	0
Purchases of marketable securities	(427,968)	0
Sales of marketable securities	59,071	0
Maturities of marketable securities	5,800	0
Net increase in restricted cash	(5,600)	0
Net cash used in investing activities	(415,815)	(21,823)
CASH FLOWS FROM FINANCING ACTIVITIES
Net proceeds from exercise of stock options	6,369	3,004
Proceeds from issuance of common stock under employee stock purchase plan	15,079	0
Payments of deferred offering costs	0	(1,116)
Net cash provided by financing activities	21,448	1,888
Net decrease in cash and cash equivalents	(398,924)	(64,425)
Cash and cash equivalents, beginning of period	604,742	192,707
Cash and cash equivalents, end of period	205,818	128,282
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for income taxes	1,827	333
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION
Property and equipment purchased but not yet paid	7,691	1,742
Vesting of early exercised stock options	486	1,096
Unpaid deferred offering costs	$ 0	$ 1,373