Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	[1]
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (124,427)	$ (115,570)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	33,590	30,000
Amortization of debt discount and debt issuance costs	7,889	0
Stock-based compensation expense	97,609	69,057
Other	82	797
Changes in operating assets and liabilities:
Accounts receivable, net	707	25
Inventory	(8,900)	(10,487)
Deferred commissions	(4,155)	(9,587)
Prepaid expenses and other assets	11,134	(186)
Accounts payable	(18,135)	201
Accrued compensation and other liabilities	(7,458)	(2,993)
Deferred revenue	39,144	24,251
Net cash provided by (used in) operating activities	27,080	(14,492)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(42,733)	(30,100)
Purchases of marketable securities	(494,507)	(95,358)
Sales of marketable securities	13,585	33,529
Maturities of marketable securities	97,793	73,681
Net cash used in investing activities	(425,862)	(18,248)
CASH FLOWS FROM FINANCING ACTIVITIES
Net proceeds from exercise of stock options	29,067	6,793
Proceeds from issuance of common stock under employee stock purchase plan	19,698	14,166
Proceeds from issuance of convertible senior notes, net of issuance costs	562,062	0
Payment for purchase of capped calls	(64,630)	0
Repurchase of common stock	(20,000)	0
Net cash provided by financing activities	526,197	20,959
Net increase (decrease) in cash, cash equivalents and restricted cash	127,415	(11,781)
Cash, cash equivalents and restricted cash, beginning of period	258,820	196,409
Cash, cash equivalents and restricted cash, end of period	386,235	184,628
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD:
Cash and cash equivalents	370,457	171,894
Restricted cash	15,778	12,734
Cash, cash equivalents and restricted cash, end of period	386,235	184,628
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for income taxes	3,023	1,661
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION
Property and equipment purchased but not yet paid	11,949	6,578
Vesting of early exercised stock options	$ 320	$ 546

[1] * Prior period information has been adjusted to reflect the adoption impact of ASC 606 and ASU 2016-18, which we adopted on February 1, 2018