Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	[1]
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (152,607)	$ (144,974)	[2],[3]
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	51,381	45,525
Amortization of debt discount and debt issuance costs	14,414	0
Stock-based compensation expense	155,938	107,920
Deferred income taxes	(4,402)	(121)
Other	(635)	1,000
Changes in operating assets and liabilities, net of effects of acquisition:
Accounts receivable, net	(62,623)	(33,630)
Inventory	(17,103)	(14,314)
Deferred commissions	(9,127)	(13,969)
Prepaid expenses and other assets	1,996	(112)
Accounts payable	11,800	11,808
Accrued compensation and other liabilities	7,592	359
Deferred revenue	87,005	54,264
Net cash provided by operating activities	83,629	13,756
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(70,807)	(44,351)
Acquisition, net of cash acquired	(13,899)	0
Purchases of marketable securities	(558,248)	(151,998)
Sales of marketable securities	18,802	46,067
Maturities of marketable securities	156,049	99,021
Net cash used in investing activities	(468,103)	(51,261)
CASH FLOWS FROM FINANCING ACTIVITIES
Net proceeds from exercise of stock options	43,342	15,761
Proceeds from issuance of common stock under employee stock purchase plan	33,444	22,137
Proceeds from issuance of convertible senior notes, net of issuance costs	562,062	0
Payment for purchase of capped calls	(64,630)	0
Repayment of debt assumed from acquisition	(6,101)	0
Repurchase of common stock	(20,000)	0
Net cash provided by financing activities	548,117	37,898
Net increase in cash, cash equivalents and restricted cash	163,643	393
Cash, cash equivalents and restricted cash, beginning of period	258,820	196,409
Cash, cash equivalents and restricted cash, end of period	422,463	196,802
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD:
Cash and cash equivalents	406,641	182,039
Restricted cash	15,822	14,763
Cash, cash equivalents and restricted cash, end of period	422,463	196,802
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for income taxes	4,121	2,410
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION
Property and equipment purchased but not yet paid	14,605	9,831
Acquisition consideration held back to satisfy potential indemnification claims	3,725	0
Vesting of early exercised stock options	$ 320	$ 794

[1] * Prior period information has been adjusted to reflect the adoption impact of ASC 606 and Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18), which we adopted on February 1, 2018

[2] * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.

[3] * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.