Pure Storage (PSTG) 10-Q 6 Dec 18 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Oct. 31, 2018	Nov. 28, 2018
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Oct. 31, 2018
Document Fiscal Year Focus	2,019
Document Fiscal Period Focus	Q3
Trading Symbol	PSTG
Entity Registrant Name	Pure Storage, Inc.
Entity Central Index Key	1,474,432
Current Fiscal Year End Date	--01-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Class A
Entity Common Stock, Shares Outstanding (in shares)		216,507,814
Class B
Entity Common Stock, Shares Outstanding (in shares)		25,108,923

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018	[1]
Current assets:
Cash and cash equivalents	$ 406,641	$ 244,057
Marketable securities	737,020	353,289
Accounts receivable, net of allowance of $1,062 and $1,052 as of January 31, 2018 and October 31, 2018	305,649	243,001
Inventory	50,737	34,497
Deferred commissions, current	24,100	21,088
Prepaid expenses and other current assets	44,657	47,552
Total current assets	1,568,804	943,484
Property and equipment, net	115,266	89,142
Deferred commissions, non-current	72,340	66,225
Intangible assets, net	21,126	5,057
Goodwill	10,997	0
Deferred income taxes, non-current	1,766	1,060
Restricted cash	15,822	14,763
Other assets, non-current	5,245	4,264
Total assets	1,811,366	1,123,995
Current liabilities:
Accounts payable	101,979	84,420
Accrued compensation and benefits	53,213	59,898
Accrued expenses and other liabilities	43,633	26,829
Deferred revenue, current	232,570	191,229
Liability related to early exercised stock options	0	320
Total current liabilities	431,395	362,696
Convertible senior notes, net	443,212	0
Deferred revenue, non-current	228,618	182,873
Other liabilities, non-current	5,813	4,025
Total liabilities	1,109,038	549,594
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, par value of $0.0001 per share— 20,000 shares authorized as of January 31, 2018 and October 31, 2018; no shares issued and outstanding as of January 31, 2018 and October 31, 2018	0	0
Class A and Class B common stock, par value of $0.0001 per share— 2,250,000 (Class A 2,000,000, Class B 250,000) shares authorized as of January 31, 2018 and October 31, 2018; 220,979 (Class A 129,502, Class B 91,477) and 241,359 (Class A 216,252, Class B 25,107) shares issued and outstanding as of January 31, 2018 and October 31, 2018	24	22
Additional paid-in capital	1,761,597	1,479,883
Accumulated other comprehensive loss	(3,099)	(1,917)
Accumulated deficit	(1,056,194)	(903,587)
Total stockholders’ equity	702,328	574,401
Total liabilities and stockholders’ equity	$ 1,811,366	$ 1,123,995
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018	[1]
Accounts receivable, allowance	$ 1,052	$ 1,062
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	2,250,000,000	2,250,000,000
Common stock, shares issued (in shares)	241,359,000	220,979,000
Common stock, shares outstanding (in shares)	241,359,000	220,979,000
Class A
Common stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	2,000,000,000	2,000,000,000
Common stock, shares issued (in shares)	216,252,136	129,502,000
Common stock, shares outstanding (in shares)	216,252,136	129,502,000
Class B
Common stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	25,107,173	91,477,000
Common stock, shares outstanding (in shares)	25,107,173	91,477,000
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	[1]	Oct. 31, 2018	Oct. 31, 2017	[1]
Revenue	$ 372,779	$ 277,591		$ 937,608	$ 684,906
Cost of revenue	123,659	95,859		316,008	235,858
Gross profit	249,120	181,732		621,600	449,048
Operating expenses:
Research and development	90,783	68,927		253,306	203,716
Sales and marketing	146,903	116,971		413,019	326,286
General and administrative	38,651	25,406		99,572	67,664
Total operating expenses	276,337	211,304		765,897	597,666
Loss from operations	(27,217)	(29,572)		(144,297)	(148,618)
Other income (expense), net	(2,889)	1,138		(7,920)	6,399
Loss before provision for income taxes	(30,106)	(28,434)		(152,217)	(142,219)
Income tax provision (benefit)	(1,926)	970		390	2,755
Net loss	$ (28,180)	$ (29,404)	[2]	$ (152,607)	$ (144,974)	[2],[3]
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.12)	$ (0.14)		$ (0.66)	$ (0.69)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	235,205	213,274		229,505	209,456
Product
Revenue	$ 298,863	$ 227,772		$ 735,449	$ 550,291
Cost of revenue	96,610	75,392		241,292	179,289
Support subscription
Revenue	73,916	49,819		202,159	134,615
Cost of revenue	$ 27,049	$ 20,467		$ 74,716	$ 56,569
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, 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 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

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	[2]	Oct. 31, 2018	Oct. 31, 2017	[2]
Statement of Comprehensive Income [Abstract]
Net loss	$ (28,180)	$ (29,404)	[1]	$ (152,607)	$ (144,974)	[1],[3]
Other comprehensive loss:
Change in unrealized net loss on available-for-sale securities	(273)	(439)		(1,182)	(157)
Comprehensive loss	$ (28,453)	$ (29,843)		$ (153,789)	$ (145,131)
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, 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 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

Condensed Consolidated Statem_3

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.

Business Overview

Business Overview	9 Months Ended
	Oct. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Overview	Business Overview Organization and Description of Business Pure Storage, Inc. (the Company, we, us, or other similar pronouns) was originally incorporated in the state of Delaware in October 2009 under the name OS76, Inc. In January 2010, we changed our name to Pure Storage, Inc. We are headquartered in Mountain View, California and have wholly owned subsidiaries throughout the world. We help innovators to build a better world with data. Our data platform replaces storage systems designed for mechanical disk with all-flash systems optimized end-to-end for solid-state memory. Our Pure1 cloud-based support and management platform simplifies storage administration and provides real-time scanning to find and fix issues. Our business model replaces the traditional forklift upgrade cycle with Evergreen Storage subscriptions to hardware and software innovation, support and maintenance.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Oct. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Basis of Presentation and Summary of Significant Accounting Policies Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and our wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Unaudited Interim Consolidated Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (U.S. GAAP) and applicable rules and regulations of the Securities and Exchange Commission (the SEC) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in our Annual Report on Form 10-K for the year ended January 31, 2018 . In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial position, results of operations, comprehensive loss and cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full fiscal year 2019 or any future period. Certain prior period amounts have been adjusted as a result of adoption of new accounting pronouncements. Refer to " Recently Adopted Accounting Pronouncements" below for further information. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and accompanying notes. Actual results could differ from these estimates. Such estimates include, but are not limited to, the determination of standalone selling price for revenue arrangements with multiple performance obligations, useful lives of intangible assets, property and equipment and deferred sales commissions, stock-based compensation, provision for income taxes including related reserves, valuation of intangible assets and goodwill, and contingent liabilities. Management bases its estimates on historical experience and on various other assumptions which management believes to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Restricted Cash Restricted cash is comprised of cash collateral related to our leases and for a vendor corporate credit card program. As of January 31, 2018 and October 31, 2018 , we had restricted cash of $14.8 million and $15.8 million on the condensed consolidated balance sheets. Marketable Securities We classify our marketable securities as available-for-sale at the time of purchase and reevaluate such classification at each balance sheet date. We may sell these securities at any time for use in current operations even if they have not yet reached maturity. As a result, we classify our securities, including those with maturities beyond twelve months, as current assets in the accompanying condensed consolidated balance sheets. We carry these securities at fair value and record unrealized gains and losses, in accumulated other comprehensive loss, which is reflected as a component of stockholders’ equity. We evaluate our securities to assess whether those with unrealized loss positions are other than temporarily impaired. We consider impairments to be other than temporary if they are related to deterioration in credit risk or if it is likely we will sell the securities before the recovery of their cost basis. Realized gains and losses from the sale of marketable securities and declines in value deemed to be other than temporary are determined on the specific identification method. To date, there have been no declines in value deemed to be other than temporary in any of our securities. Realized gains and losses are reported in other income (expense), net in the condensed consolidated statements of operations. Business Combination We allocate the purchase price to the assets acquired and liabilities assumed based on their estimated fair values. The excess of the purchase price over the fair values of the assets acquired and liabilities assumed is recorded as goodwill. The results of operations of the acquired businesses are included in our condensed consolidated financial statements from the date of acquisition. Acquisition-related expenses are expensed as incurred. Deferred Commissions Deferred commissions consist of incremental costs paid to our sales force to obtain customer contracts. Deferred commissions related to product revenues are recognized upon transfer of control to customers and deferred commissions related to support subscription revenue are amortized over an expected useful life of six years. We determine the expected useful life based on an estimated benefit period by evaluating our technology development life cycle, expected customer relationship period, and other factors. We classify deferred commissions as current and non-current on our condensed consolidated balance sheets based on the timing of when we expect to recognize the expense. Amortization of deferred commissions is included in sales and marketing expense in the condensed consolidated statements of operations. Changes in total deferred commissions during the periods presented are as follows (in thousands): Three Months Ended October 31, 2018 Nine Months Ended October 31, 2018 Beginning balance (1) $ 91,469 $ 87,313 Additions 31,884 71,887 Recognition of deferred commissions (26,913 ) (62,760 ) Ending balance as of October 31, 2018 $ 96,440 $ 96,440 ____________________ (1) Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606. Of the $96.4 million total deferred commissions balance as of October 31, 2018 , we expect to recognize approximately 25% as commission expense over the next 12 months and the remainder thereafter. There was no impairment related to capitalized commissions for the three and nine months ended October 31, 2017 and 2018 . Deferred Revenue Deferred revenue primarily consists of amounts that have been invoiced but that have not yet been recognized as revenue and performance obligations pertaining to support subscription services. The current portion of deferred revenue represents the amounts that are expected to be recognized as revenue within one year of the condensed consolidated balance sheet dates. Changes in total deferred revenue during the periods presented are as follows (in thousands): Three Months Ended October 31, 2018 Nine Months Ended October 31, 2018 Beginning balance (1) $ 413,247 $ 374,102 Additions 122,681 290,463 Recognition of deferred revenue (74,740 ) (203,377 ) Ending balance as of October 31, 2018 $ 461,188 $ 461,188 ____________________ (1) Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606. During the three and nine months ended October 31, 2017 , we recognized $47.3 million and $108.2 million in revenue pertaining to deferred revenue as of the beginning of each period. During the three and nine months ended October 31, 2018 , we recognized $67.0 million and $151.4 million in revenue pertaining to deferred revenue as of the beginning of each period. Of the $461.2 million remaining performance obligations as of October 31, 2018 , we expect to recognize approximately 50% as revenue over the next 12 months and the remainder thereafter. Substantially all of our contracted but not invoiced performance obligations are subject to cancellation and, therefore, are not considered in our remaining performance obligations. Revenue Recognition We derive revenue from two sources: (1) product revenue which includes hardware and embedded software and (2) support subscription revenue which includes customer support, hardware maintenance, and software upgrades on a when-and-if-available basis. Our product revenue is derived from the sale of storage hardware and operating system software that is integrated into the hardware. We typically recognize product revenue upon transfer of control to our customers. Products are typically shipped directly by us to customers, and our channel partners do not stock our inventory. Our support subscription revenue is derived from the sale of support subscription, which includes the right to receive unspecified software upgrades and enhancements on a when-and-if-available basis, bug fixes, parts replacement services related to the hardware, as well as access to our cloud-based management and support platform. Revenue related to support subscription is recognized ratably over the contractual term, which generally ranges from one to six years and represents our performance obligations period. The vast majority of our products are sold with support subscription agreements, which typically commence upon transfer of control of the corresponding products to our customers. Costs to service the support subscription are expensed as incurred. In addition, our Evergreen Storage program provides our customers who continually maintain active support subscription agreements for three years with an included controller refresh with each additional three year support subscription renewal. In accordance with revenue recognition guidance, the controller refresh represents an additional performance obligation and the allocated revenue is recognized in the period in which these controllers are shipped. We recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration we expect to be entitled in exchange for those goods or services. This is achieved through applying the following five-step approach: • Identification of the contract, or contracts, with a customer • Identification of the performance obligations in the contract • Determination of the transaction price • Allocation of the transaction price to the performance obligations in the contract • Recognition of revenue when, or as, we satisfy a performance obligation When applying this five-step approach, we apply judgment in determining the customer's ability and intention to pay, which is based on a variety of factors including the customer's historical payment experience and/or published credit and financial information pertaining to the customer. To the extent a customer contract includes multiple promised goods or services, we determine whether promised goods or services are capable of being distinct in the context of the contract to be accounted for as a combined performance obligation. We allocate transaction price to each performance obligation for contracts that contain multiple performance obligations based on a relative standalone selling price, taking into account available information such as market conditions and internally approved pricing guidelines related to performance obligations. Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB), issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09 or ASC 606), requiring an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASC 606 supersedes nearly all existing revenue recognition guidance under U.S. GAAP upon its effective date. The standard permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of applying the standard recognized at the date of application (cumulative catch-up transition method). We adopted the standard using the full retrospective method beginning February 1, 2018, for the year ending January 31, 2019, and our historical financial information for the years ended January 31, 2017 and 2018 has been adjusted to conform to the new standard. The most significant impact of the standard related to the removal of limitation on contingent revenue, resulting in an increase in product revenue and a decrease in support subscription revenue. In addition, the adoption of ASC 606 also resulted in differences in the timing of recognition of sales commissions. While the adoption of the standard changes certain line items within the net cash flow from operating activities, it had no impact on the net cash provided by or used in operating, investing, or financing activities on our condensed consolidated statements of cash flows. The following line items on our condensed consolidated balance sheet as of January 31, 2018 have been adjusted to reflect the adoption of ASC 606 (in thousands): As of January 31, 2018 As Previously Reported Adjustment As Adjusted Assets: Deferred commissions, current $ 22,437 $ (1,349 ) $ 21,088 Deferred commissions, non-current 20,288 45,937 66,225 Total deferred commissions $ 42,725 $ 44,588 $ 87,313 Liabilities: Deferred revenue, current $ 209,377 $ (18,148 ) $ 191,229 Deferred revenue, non-current 196,632 (13,759 ) 182,873 Total deferred revenue $ 406,009 $ (31,907 ) $ 374,102 Stockholders' equity: Accumulated deficit $ (980,082 ) $ 76,495 $ (903,587 ) The following line items on our unaudited condensed consolidated statement of operations for the three and nine months ended October 31, 2017 have been adjusted to reflect the adoption of ASC 606 (in thousands, except per share data): Three Months Ended October 31, 2017 Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted As Previously Reported Adjustment As Adjusted Revenue: Product $ 223,196 $ 4,576 $ 227,772 $ 536,634 $ 13,657 $ 550,291 Support subscription 54,478 (4,659 ) 49,819 148,132 (13,517 ) 134,615 Total revenue $ 277,674 $ (83 ) $ 277,591 $ 684,766 $ 140 $ 684,906 Gross profit $ 181,815 $ (83 ) $ 181,732 $ 448,908 $ 140 $ 449,048 Sales and marketing $ 129,299 $ (12,328 ) $ 116,971 $ 346,896 $ (20,610 ) $ 326,286 Total operating expenses $ 223,632 $ (12,328 ) $ 211,304 $ 618,276 $ (20,610 ) $ 597,666 Loss from operations $ (41,817 ) $ 12,245 $ (29,572 ) $ (169,368 ) $ 20,750 $ (148,618 ) Loss before provision for income taxes $ (40,679 ) $ 12,245 $ (28,434 ) $ (162,969 ) $ 20,750 $ (142,219 ) Net loss $ (41,649 ) $ 12,245 $ (29,404 ) $ (165,724 ) $ 20,750 $ (144,974 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.20 ) $ 0.06 $ (0.14 ) $ (0.79 ) $ 0.10 $ (0.69 ) Unaudited revenue by geographic location based on bill-to location, which reflects the adoption impact of ASC 606, are as follows (in thousands): Three Months Ended October 31, 2017 Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted As Previously Reported Adjustment As Adjusted Revenue: United States $ 192,977 $ (58 ) $ 192,919 $ 504,937 $ 108 $ 505,045 Rest of the world 84,697 (25 ) 84,672 179,829 32 179,861 Total revenue $ 277,674 $ (83 ) $ 277,591 $ 684,766 $ 140 $ 684,906 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18), which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and restricted cash. We adopted ASU 2016-18 effective February 1, 2018 on a retrospective basis. Upon adoption, restricted cash is included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The adoption of this standard increased our previously reported net cash flow from investing activities for the periods in which there were changes in restricted cash but did not impact our net cash flow from operating activities or financing activities presented on our consolidated statements of cash flows. The following line items in our unaudited condensed consolidated statement of cash flows for the nine months ended October 31, 2017 have been adjusted to reflect the adoption of ASU 2016-18 and ASC 606 (in thousands): Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted Net loss (1) $ (165,724 ) $ 20,750 $ (144,974 ) Adjustments to reconcile net loss to net cash provided by operating activities: Deferred commissions (1) $ (7,629 ) $ (6,340 ) $ (13,969 ) Accrued compensation and other liabilities (1) $ 14,629 $ (14,270 ) $ 359 Deferred revenue (1) $ 54,404 $ (140 ) $ 54,264 Cash provided by operating activities $ 13,756 $ — $ 13,756 Net increase in restricted cash (2) $ (2,029 ) $ 2,029 $ — Net cash used in investing activities (2) $ (53,290 ) $ 2,029 $ (51,261 ) Net increase (decrease) in cash, cash equivalents and restricted cash (2) $ (1,636 ) $ 2,029 $ 393 Cash, cash equivalents and restricted cash, beginning of period (2) $ 183,675 $ 12,734 $ 196,409 Cash, cash equivalents and restricted cash, end of period (2) $ 182,039 $ 14,763 $ 196,802 _____________________________________________________ (1) Adjustment pertaining to the adoption of ASC 606. (2) Adjustment pertaining to the adoption of ASU 2016-18. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718) (ASU 2018-07). ASU 2018-07 aligns the accounting for share-based awards to employees and non-employees to follow the same model. The new standard is effective for fiscal years beginning after December 15, 2018 using a modified retrospective transition approach. Early adoption is permitted. We adopted this standard for the three and nine months ended October 31, 2018 and the adoption of this standard did not materially impact our consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires lessees to recognize all leases with terms in excess of one year on their balance sheet as a right-of-use asset and a lease liability at the commencement date. The new standard also simplifies the accounting for sale and leaseback transactions. ASU 2016-02 requires the use of the modified retrospective method for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In July 2018, the FASB issued ASU No. 2018-10, Leases (Topic 842), Codification Improvements to Topic 842, Leases (ASU 2018-10) and ASU No. 2018-11, Leases (Topic 842), Targeted Improvements (ASU 2018-11). ASU 2018-11 provides a new transition method in which an entity can initially apply the new lease standards at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. These standards will be effective for us beginning on February 1, 2019 and early adoption is permitted. We expect to apply the new transition method prescribed by ASU 2018-11 at the adoption date. We are currently evaluating the impact of these standards on our consolidated financial statements and expect that most of our operating lease commitments will be subject to the new standard and recognized as lease liabilities and right-of-use assets, which will increase our total assets and total liabilities upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 amends guidance on reporting credit losses for assets held at amortized cost basis and available-for-sale debt securities to require that credit losses on available-for-sale debt securities be presented as an allowance rather than as a write-down. The measurement of credit losses for newly recognized financial assets and subsequent changes in the allowance for credit losses are recorded in the statements of operations. The amendments in this update will be effective for us beginning on February 1, 2020 with early adoption permitted on or after February 1, 2019. We are currently evaluating the impact of this standard on our consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350) : Simplifying the Test for Goodwill Impairment , which eliminates Step 2 from the goodwill impairment test. This standard is effective, on a prospective basis, for our goodwill impairment tests beginning February 1, 2020. Early adoption is permitted. We are evaluating the impact of this standard on our consolidated financial statements. In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This standard allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act) and requires certain disclosures about stranded tax effects. This standard will be effective for us beginning February 1, 2019 and should be applied either in the period of adoption or retrospectively. Early adoption is permitted. We do not expect this standard to have any impact on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (ASU 2018-13) which amended its conceptual framework to improve the effectiveness of disclosures in notes to financial statements. ASU 2018-13 eliminates such disclosures around the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. The guidance also adds new disclosure requirements for Level 3 measurements. ASU 2018-13 is effective for us beginning February 1, 2020. Early adoption is permitted. We are currently evaluating the impact of this standard on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). ASC 2018-15 aligns the requirements for capitalizing implementation costs in a cloud computing arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This standard will be effective for us beginning February 1, 2020 and should be applied either retrospectively or prospectively. Early adoption is permitted. We are currently evaluating the impact of this standard on our consolidated financial statements. In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification , amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. This final rule was effective on November 5, 2018. We are evaluating the impact of this guidance on our condensed consolidated financial statements and expect to adopt this guidance in the first quarter of fiscal 2020.

Financial Instruments

Financial Instruments	9 Months Ended
	Oct. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Financial Instruments	Financial Instruments Fair Value Measurements We measure our cash equivalents, marketable securities, and restricted cash at fair value on a recurring basis. We define fair value as the exchange price that would be received from sale of an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. We measure our financial assets and liabilities at fair value at each reporting period using a fair value hierarchy which requires us to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s classification within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs may be used to measure fair value: • Level 1 - Observable inputs are unadjusted quoted prices in active markets for identical assets or liabilities; • Level 2 - Observable inputs are quoted prices for similar assets and liabilities in active markets or inputs other than quoted prices that are observable for the assets or liabilities, either directly or indirectly through market corroboration, for substantially the full term of the financial instruments; and • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. These inputs are based on our own assumptions used to measure assets and liabilities at fair value and require significant management judgment or estimation. We classify our cash equivalents, marketable securities and restricted cash within Level 1 or Level 2 because they are valued using either quoted market prices or inputs other than quoted prices which are directly or indirectly observable in the market, including readily-available pricing sources for the identical underlying security which may not be actively traded. Our fixed income available-for-sale securities consist of high quality, investment grade securities from diverse issuers. The valuation techniques used to measure the fair value of our marketable securities were derived from non-binding market consensus prices that are corroborated by observable market data or quoted market prices for similar instruments. In addition to our cash equivalents, marketable securities, and restricted cash, we measure the fair value of our convertible senior notes (the Notes) on a quarterly basis for disclosure purposes. We consider the fair value of the Notes at October 31, 2018 to be a Level 2 measurement due to limited trading activity of the Notes. Refer to Note 6 for further information. Cash Equivalents, Marketable Securities and Restricted Cash The following tables summarize our cash equivalents, marketable securities and restricted cash by significant investment categories as of January 31, 2018 and October 31, 2018 (in thousands): As of January 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash Equivalents Marketable Securities Restricted Cash Level 1 Money market accounts $ — $ — $ — $ 32,057 $ 17,294 $ — $ 14,763 Level 2 U.S. government treasury notes 131,643 — (651 ) 130,992 10,172 120,820 — U.S. government agencies 47,229 — (333 ) 46,896 — 46,896 — Corporate debt securities 186,506 116 (1,049 ) 185,573 — 185,573 — Total $ 365,378 $ 116 $ (2,033 ) $ 395,518 $ 27,466 $ 353,289 $ 14,763 As of October 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash Equivalents Marketable Securities Restricted Cash Level 1 Money market accounts $ — $ — $ — $ 26,298 $ 10,476 $ — $ 15,822 Level 2 U.S. government treasury notes 323,212 — (891 ) 322,321 62,392 259,929 — U.S. government agencies 73,362 — (355 ) 73,007 2,992 70,015 — Corporate debt securities 377,468 31 (1,830 ) 375,669 — 375,669 — Foreign government bonds 6,657 1 (14 ) 6,644 — 6,644 — Asset-backed securities 24,804 — (41 ) 24,763 — 24,763 — Total $ 805,503 $ 32 $ (3,131 ) $ 828,702 $ 75,860 $ 737,020 $ 15,822 The amortized cost and estimated fair value of our marketable securities are shown below by contractual maturity (in thousands): As of October 31, 2018 Amortized Cost Fair Value Due within one year $ 367,860 $ 366,886 Due in one to five years 372,255 370,134 Total $ 740,115 $ 737,020 The gross unrealized losses on our investments as of October 31, 2018 were temporary in nature. The following table presents gross unrealized losses and fair values for those investments that were in a continuous unrealized loss position as of October 31, 2018 , aggregated by investment category (in thousands): Less than 12 months Greater than 12 months Total Fair Value Unrealized Loss Fair Unrealized Fair Unrealized U.S. government treasury notes $ 282,905 $ (535 ) $ 39,416 $ (356 ) $ 322,321 $ (891 ) U.S. government agencies 47,927 (143 ) 25,080 (212 ) 73,007 (355 ) Corporate debt securities 270,140 (1,080 ) 72,743 (750 ) 342,883 (1,830 ) Foreign government bonds 5,145 (14 ) — — 5,145 (14 ) Asset-backed securities 24,763 (41 ) — — 24,763 (41 ) Total $ 630,880 $ (1,813 ) $ 137,239 $ (1,318 ) $ 768,119 $ (3,131 ) Realized gains or losses on sale of marketable securities were not significant for all periods presented.

Business Combination

Business Combination	9 Months Ended
	Oct. 31, 2018
Business Combinations [Abstract]
Business Combination	Business Combination In August 2018, we completed the acquisition of StorReduce, Inc. (StorReduce), a privately-held, cloud-first software-defined storage solution for managing large-scale unstructured data. Acquisition-related costs were immaterial and were expensed as incurred. The purchase consideration was $20.5 million in cash (net of cash acquired) after repayment of $6.1 million of debt assumed and payment of $1.1 million in transaction fees on behalf of StorReduce. The purchase price was allocated as follows: $17.7 million in developed technology which will be amortized over seven years, $11.0 million of goodwill, $4.5 million in net liabilities assumed, and $3.7 million in deferred tax liabilities. The deferred tax liability was primarily a result of the difference in the book basis and tax basis related to the developed technology. Goodwill is primarily attributable to the assembled workforce and synergies from integrating StorReduce's technology with our storage portfolio and is not expected to be deductible for tax purposes. We held back approximately $3.7 million in cash to satisfy potential indemnification claims through August 2019. In addition, we granted 622,482 RSUs to former StorReduce employees with a total grant date fair value of $13.6 million , subject to continuous employment. These awards are recognized as stock-based compensation over the related vesting period. The results of StorReduce are included in our consolidated statements of operations since the acquisition date, including revenues and net loss, and are not material. Pro forma results of operations have not been presented because the acquisition is not material to our results of operations.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Oct. 31, 2018
Balance Sheet Components Disclosure [Abstract]
Balance Sheet Components	Balance Sheet Components Inventory Inventory consists of the following (in thousands): As of As of Raw materials $ 1,181 $ 4,880 Finished goods 33,316 45,857 Inventory $ 34,497 $ 50,737 Property and Equipment, Net Property and equipment, net, consists of the following (in thousands): As of As of Test equipment $ 142,311 $ 166,936 Computer equipment and software 72,329 103,366 Furniture and fixtures 5,363 5,619 Leasehold improvements 15,032 31,707 Total property and equipment 235,035 307,628 Less: accumulated depreciation and amortization (145,893 ) (192,362 ) Property and equipment, net $ 89,142 $ 115,266 Depreciation and amortization expense was $15.2 million and $16.9 million for the three months ended October 31, 2017 and 2018 , and $44.4 million and $49.8 million for the nine months ended October 31, 2017 and 2018 . Intangible Assets, Net Intangible assets, net consist of the following (in thousands): As of As of Gross Carrying Value Accumulated Amortization Net Carrying Amount Gross Carrying Value Accumulated Amortization Net Carrying Amount Technology patents $ 10,125 $ (5,068 ) $ 5,057 $ 10,125 $ (6,196 ) $ 3,929 Developed technology — — — 17,700 (503 ) 17,197 Intangible assets, net $ 10,125 $ (5,068 ) $ 5,057 $ 27,825 $ (6,699 ) $ 21,126 Total intangible assets amortization expense was $0.4 million and $0.9 million for the three months ended October 31, 2017 and 2018 , and $1.1 million and $1.6 million for the nine months ended October 31, 2017 and 2018 . The weighted-average remaining amortization period is 2.6 years for technology patents and 6.8 years for developed technology. Amortization expense related to the technology patents is included in general and administrative expenses. Amortization of developed technology is included in cost of product revenue. As of October 31, 2018 , future expected amortization expense for intangible assets is as follows (in thousands): Fiscal Years Ending January 31, Estimated Future Amortization Expense Remainder of 2019 $ 1,008 2020 4,032 2021 4,032 2022 3,074 2023 2,529 Thereafter 6,451 Total $ 21,126 Goodwill The change in the carrying amount of goodwill is as follows (in thousands): Amount Balance as of January 31, 2018 $ — Goodwill acquired 10,997 Balance as of October 31, 2018 $ 10,997 Accrued Expenses and Other Liabilities Accrued expenses and other liabilities consist of the following (in thousands): As of As of Taxes payable $ 4,052 $ 6,907 Accrued marketing 5,928 8,561 Accrued travel and entertainment expenses 4,386 4,108 Acquisition consideration held back — 3,725 Other accrued liabilities 12,463 20,332 Total accrued expenses and other liabilities $ 26,829 $ 43,633

Convertible Senior Notes

Convertible Senior Notes	9 Months Ended
	Oct. 31, 2018
Debt Disclosure [Abstract]
Convertible Senior Notes	Convertible Senior Notes In April 2018, we issued $575.0 million in principal amount of 0.125% convertible senior notes due 2023, in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act and received proceeds of $562.1 million , after deducting the underwriters’ discounts and commissions. The Notes are governed by an indenture (the Indenture) between us, as the issuer, and U.S. Bank National Association, as trustee. The Notes are our senior unsecured obligations. The Indenture does not contain any financial covenants or restrictions on the payments of dividends, the incurrence of indebtedness, or the issuance or repurchase of securities by us or any of our subsidiaries. The Notes mature on April 15, 2023 unless repurchased or redeemed by us or converted in accordance with their terms prior to the maturity date. Interest is payable semi-annually in arrears on April 15 and October 15 of each year, beginning on October 15, 2018. The Notes are convertible for up to 21,884,155 shares of our common stock at an initial conversion rate of approximately 38.0594 shares of Class A common stock per $1,000 principal amount, which is equal to an initial conversion price of approximately $26.27 per share of Class A common stock, subject to adjustment. Holders of the Notes may surrender their Notes for conversion at their option at any time prior to the close of business on the business day immediately preceding October 15, 2022, only under the following circumstances: • during any fiscal quarter commencing after the fiscal quarter ended on July 31, 2018 (and only during such fiscal quarter), if the last reported sale price of our Class A common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the conversion price for the Notes on each applicable trading day; • during the five business day period after any five consecutive trading day period (the measurement period), in which the trading price per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our Class A common stock and the conversion rate for the Notes on each such trading day; • if we call any or all of the Notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or • upon the occurrence of specified corporate events. On or after October 15, 2022 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert all or any portion of their Notes at any time regardless of the foregoing circumstances. Upon conversion, holders will receive cash, shares of our Class A common stock, or a combination of cash and shares of our Class A common stock, at our election. We intend to settle the principal of the Notes in cash. The conversion price will be subject to adjustment in some events. Following certain corporate events that occur prior to the maturity date or following our issuance of a notice of redemption, we will increase the conversion rate for a holder who elects to convert its Notes in connection with such corporate event or during the related redemption period in certain circumstances. Additionally, upon the occurrence of a corporate event that constitutes a “fundamental change” per the Indenture, holders of the Notes may require us to repurchase for cash all or a portion of the Notes at a purchase price equal to 100% of the principal amount of the Notes plus accrued and unpaid contingent interest. We may not redeem the Notes prior to April 20, 2021. We may redeem for cash all or any portion of the Notes, at our option, on or after April 20, 2021 if the last reported sale price of our Class A common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending not more than two trading days immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the Notes. In accounting for the issuance of the Notes, we separated the Notes into liability and equity components. The carrying amount of the liability component was determined by measuring the fair value of a similar liability that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was calculated by deducting the fair value of the liability component from the principal amount of the Notes as a whole. The difference between the principal amount of the Notes and the liability component (the debt discount) is amortized to interest expense in the condensed consolidated statements of operations using the effective interest method over the term of the Notes. The equity component of the Notes is included in additional paid-in capital in the condensed consolidated balance sheets and is not remeasured as long as it continues to meet the conditions for equity classification. In accounting for the transaction costs related to the issuance of the Notes, we allocated the total amount incurred to the liability and equity components using the same proportions as the initial carrying value of the Notes. Transaction costs attributable to the liability component were netted with the principal amount of the Notes in the condensed consolidated balance sheets and are being amortized to interest expense in the condensed consolidated statements of operations using the effective interest method over the term of the Notes. Transaction costs attributable to the equity component were netted with the equity component of the Notes in additional paid-in capital in the condensed consolidated balance sheets. Upon the issuance of the Notes, we recorded total debt issuance costs of $12.9 million , of which approximately $9.8 million was allocated to the Notes and approximately $3.1 million was allocated to additional paid-in capital. The Notes consisted of the following (in thousands): As of Liability: Principal $ 575,000 Less: debt discount, net of amortization (122,891 ) Less: debt issuance costs, net of amortization (8,897 ) Net carrying amount of the Notes $ 443,212 Stockholders' equity: Allocated value of the conversion feature $ 136,333 Less: debt issuance costs (3,068 ) Additional paid-in capital $ 133,265 The total estimated fair value of the Notes as of October 31, 2018 was approximately $586.5 million . The fair value was determined based on the closing trading price per $100 of the Notes as of the last day of trading for the period. The fair value of the Notes is primarily affected by the trading price of our common stock and market interest rates. Based on the closing price of our Class A common stock of $20.18 on October 31, 2018 , the if-converted value of the Notes of $441.6 million was less than its principal amount. The following table sets forth total interest expense recognized related to the Notes for the three and nine months ended October 31, 2018 (in thousands): Three Months Ended October 31, 2018 Nine Months Ended October 31, 2018 Amortization of debt discount $ 6,084 $ 13,441 Amortization of debt issuance costs 441 973 Total amortization of debt discount and debt issuance costs 6,525 14,414 Contractual interest expense 181 405 Total interest expense related to the Notes $ 6,706 $ 14,819 Effective interest rate of the liability component 5.6 % 5.6 % In connection with the offering of the Notes, we paid $64.6 million to enter into capped call transactions with certain of the underwriters and their affiliates (the Capped Calls), whereby we have the option to purchase a total of 21,884,155 shares of our Class A common stock upon any conversion of Notes and/or offset any cash payments we are required to make in excess of the principal amount of the Notes, as the case may be, with such reduction or offset subject to a cap initially equal to $39.66 per share (which represents a premium of 100% over the last reported sales price of our Class A common stock on April 4, 2018), subject to certain adjustments (the Cap Price). The cost of the Capped Calls was accounted for as a reduction to additional paid-in capital on the condensed consolidated balance sheet. The Capped Calls are intended to reduce or offset potential dilution of our common stock upon any conversion of the Notes, subject to a cap based on the Cap Price. Impact on Earnings Per Share The Notes will not impact our diluted earnings per share until the average market price of our Class A common stock exceeds the conversion price of $26.27 per share, as we intend to settle the principal amount of the Notes in cash upon conversion. We are required under the treasury stock method to compute the potentially dilutive shares of common stock related to the Notes for periods we report net income. However, upon conversion, there will be no economic dilution from the Notes until the average market price of our Class A common stock exceeds the Cap Price of $39.66 per share, as exercise of the Capped Calls offsets any dilution from the Notes from the conversion price up to the Cap Price. Capped Calls are excluded from the calculation of diluted earnings per share, as they would be anti-dilutive under the treasury stock method.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Oct. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases As of January 31, 2018 and October 31, 2018 , the aggregate future minimum payments under non-cancelable operating leases were approximately $113.0 million and $149.9 million . Letters of Credit In connection with a lease amendment executed in March 2018, we issued a letter of credit of $1.5 million . As of January 31, 2018 and October 31, 2018 , we had outstanding letters of credit in the aggregate amount of $9.6 million and $10.8 million , in connection with our facility leases. The letters of credit are collateralized by restricted cash and mature on various dates through August 2029 . Legal Matters From time to time, we have become involved in claims and other legal matters arising in the normal course of business. We investigate these claims as they arise. Although claims are inherently unpredictable, we currently are not aware of any matters that we expect to have a material adverse effect on our business, financial position, results of operations or cash flows. Accordingly, we have not recorded any loss contingency on our condensed consolidated balance sheet as of October 31, 2018 . Indemnification Our arrangements generally include certain provisions for indemnifying customers against liabilities if our products or services infringe a third party’s intellectual property rights. Other guarantees or indemnification arrangements include guarantees of product and service performance and standby letters of credit for lease facilities. It is not possible to determine the maximum potential amount under these indemnification obligations due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. To date, we have not incurred any material costs as a result of such obligations and have not accrued any liabilities related to such obligations in the condensed consolidated financial statements. In addition, we indemnify our officers, directors and certain key employees while they are serving in good faith in their respective capacities. To date, there have been no claims under any indemnification provisions.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Oct. 31, 2018
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock We have 20,000,000 authorized shares of undesignated preferred stock, the rights, preferences and privileges of which may be designated from time to time by our board of directors. As of October 31, 2018 , there were no shares of preferred stock issued or outstanding. Class A and Class B Common Stock We have two classes of authorized common stock, Class A common stock and Class B common stock. As of October 31, 2018 , we had 2,000,000,000 shares of Class A common stock authorized with a par value of $0.0001 per share and 250,000,000 shares of Class B common stock authorized with a par value of $0.0001 per share. As of October 31, 2018 , 216,252,136 shares of Class A common stock were issued and outstanding and 25,107,173 shares of Class B common stock were issued and outstanding. Subsequent to October 31, 2018 , all outstanding Class B common stock converted to Class A common stock as discussed in Note 13. Repurchase of Common Stock Concurrent with the issuance of the Notes (see Note 6), we repurchased and retired 1,008,573 shares, or $20.0 million , of our Class A common stock at $19.83 per share, which was equal to the closing price per share of our Class A common stock on April 4, 2018, the date of the pricing of the offering of the Notes. The repurchased shares were recorded as a reduction of additional paid-in capital on the condensed consolidated balance sheet.

Equity Incentive Plans

Equity Incentive Plans	9 Months Ended
	Oct. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Incentive Plans	Equity Incentive Plans Equity Incentive Plans We maintain two equity incentive plans: the 2009 Equity Incentive Plan (the 2009 Plan) and the 2015 Equity Incentive Plan (the 2015 Plan). In August 2015, our board of directors adopted, and in September 2015 our stockholders approved, the 2015 Plan, which became effective in connection with our initial public offering (IPO) and serves as the successor to the 2009 Plan. The 2015 Plan provides for grants of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards, and other forms of stock awards to our employees, directors and consultants. The exercise price of stock options will generally not be less than 100% of the fair market value of our common stock on the date of grant, as determined by our board of directors. Our equity awards generally vest over a two to four year period and expire no later than ten years from the date of grant. 2015 Employee Stock Purchase Plan In August 2015, our board of directors adopted, and our stockholders approved, the 2015 Employee Stock Purchase Plan (2015 ESPP), which became effective in connection with our IPO. The 2015 ESPP allows eligible employees to purchase shares of our Class A common stock at a discount through payroll deductions of up to 30% of their eligible compensation, subject to a cap of 3,000 shares on any purchase date or $25,000 in any calendar year (as determined under applicable tax rules). The 2015 ESPP provides for 24 month offering periods beginning March 16th and September 16th of each year, and each offering period consists of four six -month purchase periods, subject to a reset provision. If the closing stock price on the offering date of a new offering falls below the closing stock price on the offering date of an ongoing offering, the ongoing offering would terminate immediately following the purchase of ESPP shares on the purchase date immediately preceding the new offering and participants in the terminated ongoing offering would automatically be enrolled in the new offering (ESPP reset), resulting in a modification. On each purchase date, eligible employees will purchase our Class A common stock at a price per share equal to 85% of the lesser of the fair market value of our Class A common stock on (1) the first trading day of the applicable offering period or (2) the purchase date. There was an ESPP reset in the three months ended April 30, 2017 that resulted in a total modification charge of $9.0 million , which is recognized over the new offering period ending March 15, 2019. We recognized stock-based compensation expense related to our 2015 ESPP of $4.7 million and $11.6 million during the three months ended October 31, 2017 and 2018 and $12.6 million and $26.2 million during the nine months ended October 31, 2017 and 2018 . As of October 31, 2018 , there was $36.3 million of unrecognized stock-based compensation expense related to our 2015 ESPP, which is expected to be recognized over a weighted-average period of approximately 0.9 years. Stock Options A summary of stock option activity under our equity incentive plans and related information is as follows: Options Outstanding Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (In Years) Aggregate Intrinsic Value (in thousands) Balance as of January 31, 2018 46,359,949 $ 7.75 6.3 $ 574,224 Options exercised (8,249,893 ) 5.26 Options forfeited/canceled (1,360,202 ) 10.04 Balance as of October 31, 2018 36,749,854 $ 8.22 5.6 $ 439,185 Vested and exercisable as of October 31, 2018 26,221,996 $ 6.38 5.2 $ 361,783 The aggregate intrinsic value of options vested and exercisable as of October 31, 2018 is calculated based on the difference between the exercise price and the closing price of $20.18 of our Class A common stock on October 31, 2018 . As of October 31, 2018 , total unrecognized employee compensation cost related to outstanding options was $40.2 million , which is expected to be recognized over a weighted-average period of approximately 1.9 years. Restricted Stock Units A summary of the restricted stock unit activity under our 2015 Plan and related information is as follows: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Aggregate Unvested balance as of January 31, 2018 17,682,646 $ 12.60 $ 356,117 Granted 11,098,371 22.49 Vested (6,429,146 ) 12.84 Forfeited (1,719,729 ) 15.57 Converted (1,142,838 ) 11.86 Unvested balance as of October 31, 2018 19,489,304 $ 17.92 $ 393,270 As of October 31, 2018 , total unrecognized employee compensation cost related to unvested restricted stock units was $316.1 million , which is expected to be recognized over a weighted-average period of approximately 3.0 years. In March 2017, we granted 750,000 performance stock units (net of 77,000 canceled units), at a target percentage of 100%, with both performance and service vesting conditions payable in common shares, from 0% to 150% of the target number granted, contingent upon the degree to which the performance condition is met. In March 2018, a total of 780,000 shares was earned based on the performance condition achieved and these shares are subject to service conditions through the vesting periods. Stock-based compensation expense for these performance stock units, recognized on an accelerated attribution method, was $1.3 million and $0.4 million for the three months ended October 31, 2017 and 2018 , and $2.9 million and $1.9 million for the nine months ended October 31, 2017 and 2018 . In August 2017, we granted 464,744 performance stock units, at a target percentage of 100% , with both performance and service vesting conditions payable in common shares, from 0% to 150% of the target number granted, contingent upon the degree to which the performance condition is met. The grant date for these awards was subsequently established when the performance condition was determined in March 2018, and these awards were contemporaneously converted to restricted stock. See below for further discussion. Restricted Stock In March 2018, we converted certain restricted stock units and performance stock units that were previously granted into 1,375,210 shares of restricted stock for corporate tax benefit purposes. Of the 1,375,210 shares of restricted stock, 697,116 shares are performance restricted stock and 678,094 shares are subject to service vesting conditions only. The conversion did not change the fair value or vesting conditions and therefore no modification accounting was required. During the nine months ended October 31, 2018 , we issued 1,954,908 shares of performance restricted stock at the maximum performance percentage of 180% , with vesting contingent upon the degree to which the performance condition is met. The shares may be earned from 0% to 180% . Actual shares earned may be lower than the aggregate maximum number dependent on the degree to which the performance condition is met, and cannot be higher than the aggregate maximum number. Any portion of shares that are not earned will be canceled. A summary of the restricted stock activity under our 2015 Plan and related information is as follows: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Aggregate Unvested balance as of January 31, 2018 — $ — $ — Granted and converted 3,330,118 19.25 Vested (116,186 ) 12.84 Unvested balance as of October 31, 2018 3,213,932 $ 19.49 $ 64,857 All unvested restricted shares are subject to cancellation to the extent vesting conditions are not met. Stock-based compensation expense for performance restricted stock is recognized on an accelerated attribution method. In the three and nine months ended October 31, 2018 , we recognized $7.5 million and $17.7 million in stock-based compensation expense relating to restricted stock. As of October 31, 2018 , total unrecognized employee compensation cost related to unvested restricted stock was $26.3 million , which is expected to be recognized over a weighted-average period of approximately 2.4 years. Stock-Based Compensation Expense The following table summarizes the components of stock-based compensation expense recognized in the condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended 2017 2018 2017 2018 Cost of revenue—product $ 143 $ 862 $ 898 $ 2,190 Cost of revenue—support subscription 2,422 3,327 6,441 8,940 Research and development 18,073 24,634 51,632 67,956 Sales and marketing 12,104 18,681 34,169 49,890 General and administrative 6,121 10,825 14,780 26,962 Total stock-based compensation expense $ 38,863 $ 58,329 $ 107,920 $ 155,938 The tax benefit related to stock-based compensation expense for all periods presented was not material.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended
	Oct. 31, 2018
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders Basic and diluted net loss per share attributable to common stockholders is presented in conformity with the two-class method required for participating securities. Basic net loss per share attributable to common stockholders is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, less shares subject to repurchase. Diluted net loss per share attributable to common stockholders is computed by giving effect to all potentially dilutive common stock equivalents including our outstanding stock options, common stock related to unvested early exercised stock options, common stock related to unvested restricted stock units and restricted stock awards, convertible senior notes to the extent dilutive, and common stock issuable pursuant to the ESPP. For purposes of calculating basic and diluted net loss per share attributable to common shareholders, these potentially dilutive common stock equivalents have been excluded from the calculation of diluted net loss per share attributable to common stockholders as their effect is anti-dilutive. The rights, including the liquidation and dividend rights, of the holders of our Class A and Class B common stock are identical, except with respect to voting. As the liquidation and dividend rights are identical, the undistributed earnings are allocated on a proportionate basis and the resulting net loss per share attributed to common stockholders will, therefore, be the same for both Class A and Class B common stock on an individual or combined basis. Subsequent to October 31, 2018 , all outstanding Class B common stock converted to Class A common stock as discussed in Note 13. The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except per share data): Three Months Ended Nine Months Ended 2017 2018 2017 2018 (As Adjusted*) (As Adjusted*) Net loss $ (29,404 ) $ (28,180 ) $ (144,974 ) $ (152,607 ) Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 213,274 235,205 209,456 229,505 Net loss per share attributable to common stockholders, basic and diluted $ (0.14 ) $ (0.12 ) $ (0.69 ) $ (0.66 ) * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018. The following weighted-average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive (in thousands): Three Months Ended Nine Months Ended 2017 2018 2017 2018 Stock options to purchase common stock 51,685 37,814 53,786 41,201 Restricted stock units 17,201 19,493 14,913 19,488 Restricted stock and early exercised stock options 196 3,277 287 2,938 Employee stock purchase plan 585 236 585 80 Total 69,667 60,820 69,571 63,707

Income Taxes

Income Taxes	9 Months Ended
	Oct. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our income tax provision (benefit) was primarily due to taxes on international operations and state income taxes. The difference between the income tax provision (benefit) that would be derived by applying the statutory rate to our loss before income taxes and the income tax provision (benefit) recorded was primarily attributable to changes in our valuation allowance, non-deductible stock-based compensation expense and the tax rate differential between the U.S. and foreign countries. In connection with the StorReduce acquisition, we recorded a net deferred tax liability which provides an additional source of taxable income to support the realizability of the pre-existing deferred tax assets and, accordingly, during the three months ended October 31, 2018 , we released $3.7 million of our U.S. valuation allowance. We continue to maintain a valuation allowance for our U.S. Federal and state deferred tax assets. As of October 31, 2018 , there were no material changes to either the nature or the amounts of the uncertain tax positions previously determined for the year ended January 31, 2018 . The Tax Act was signed into law on December 22, 2017. The new legislation decreases the U.S. corporate federal income tax rate from 35% to 21% effective January 1, 2018. The Tax Act also includes a number of other provisions including the elimination of loss carrybacks and limitations on the use of future losses, limitations on the deductibility of executive compensation, limitation or modification on the deductibility of certain business expenses, the transition of U.S. international taxation from a worldwide tax system to a territorial system, and the introduction of a base erosion and anti-abuse tax. Under the Tax Act, the Global Intangible Low-Taxed Income (GILTI) provision taxes foreign income in excess of a deemed return on tangible assets of foreign corporations. Under U.S. GAAP, companies are allowed to make an accounting policy election to either (i) account for GILTI as a component of tax expense in the period in which a company is subject to the rules -- the period cost method, or (ii) account for GILTI in a company’s measurement of deferred taxes -- the deferred method. Because of the complexity of the new tax rules, we have not yet made an accounting policy election and are continuing to assess the impact of the Tax Act during the one-year measurement period from the Tax Act enactment date as allowed by Staff Accounting Bulletin No. 118 (SAB 118) issued in connection with the Tax Act. We expect to complete the accounting for the tax effects of the Tax Act in calendar year 2018.

Segment Information

Segment Information	9 Months Ended
	Oct. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information Our chief operating decision maker is a group comprised of our Chief Executive Officer, our Chief Financial Officer, and our President. This group reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. We have one business activity and there are no segment managers who are held accountable for operations or operating results. Accordingly, we have a single reportable segment. Disaggregation of Revenue The following table depicts the disaggregation of revenue by geographic area based on the billing address of our customers and is consistent with how we evaluate our financial performance (in thousands): Three Months Ended Nine Months Ended 2017 2018 2017 2018 (As Adjusted*) (As Adjusted*) United States $ 192,919 $ 263,488 $ 505,045 $ 678,166 Rest of the world 84,672 109,291 179,861 259,442 Total revenue $ 277,591 $ 372,779 $ 684,906 $ 937,608 * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018. Long-Lived Assets by Geographic Area Long-lived assets by geographic area are summarized as follows (in thousands): As of As of United States $ 85,430 $ 110,850 Rest of the world 3,712 4,416 Total long-lived assets $ 89,142 $ 115,266

Subsequent Event

Subsequent Event	9 Months Ended
	Oct. 31, 2018
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events Housing Trust Silicon Valley Note In November 2018, we purchased a $5.0 million 1.5% senior note issued by Housing Trust Silicon Valley, a nonprofit community development financial institution, to support affordable homes in the San Francisco Bay Area. This note matures on October 31, 2023. Interest is payable semi-annually on April 30 and October 31 of each year. Conversion of Class B Common Stock to Class A Common Stock On December 4, 2018, all outstanding shares of our Class B common stock automatically converted into the same number of shares of our Class A common stock pursuant to the terms of our amended and restated certificate of incorporation, which provided that each share of our Class B common stock convert automatically into Class A common stock when the outstanding shares of Class B common stock represent less than 10% of the aggregate number of shares of the then outstanding Class A common stock and Class B common stock. No additional Class B shares may be issued following the conversion. The conversion does not impact our basic or diluted net loss per share attributable to common stockholders or our financial performance.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Oct. 31, 2018
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and our wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Unaudited Interim Consolidated Financial Information	Unaudited Interim Consolidated Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (U.S. GAAP) and applicable rules and regulations of the Securities and Exchange Commission (the SEC) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in our Annual Report on Form 10-K for the year ended January 31, 2018 . In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial position, results of operations, comprehensive loss and cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full fiscal year 2019 or any future period. Certain prior period amounts have been adjusted as a result of adoption of new accounting pronouncements. Refer to " Recently Adopted Accounting Pronouncements" below for further information.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and accompanying notes. Actual results could differ from these estimates. Such estimates include, but are not limited to, the determination of standalone selling price for revenue arrangements with multiple performance obligations, useful lives of intangible assets, property and equipment and deferred sales commissions, stock-based compensation, provision for income taxes including related reserves, valuation of intangible assets and goodwill, and contingent liabilities. Management bases its estimates on historical experience and on various other assumptions which management believes to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Restricted Cash	Restricted Cash Restricted cash is comprised of cash collateral related to our leases and for a vendor corporate credit card program.
Marketable Securities	Marketable Securities We classify our marketable securities as available-for-sale at the time of purchase and reevaluate such classification at each balance sheet date. We may sell these securities at any time for use in current operations even if they have not yet reached maturity. As a result, we classify our securities, including those with maturities beyond twelve months, as current assets in the accompanying condensed consolidated balance sheets. We carry these securities at fair value and record unrealized gains and losses, in accumulated other comprehensive loss, which is reflected as a component of stockholders’ equity. We evaluate our securities to assess whether those with unrealized loss positions are other than temporarily impaired. We consider impairments to be other than temporary if they are related to deterioration in credit risk or if it is likely we will sell the securities before the recovery of their cost basis. Realized gains and losses from the sale of marketable securities and declines in value deemed to be other than temporary are determined on the specific identification method. To date, there have been no declines in value deemed to be other than temporary in any of our securities. Realized gains and losses are reported in other income (expense), net in the condensed consolidated statements of operations.
Business Combination	Business Combination We allocate the purchase price to the assets acquired and liabilities assumed based on their estimated fair values. The excess of the purchase price over the fair values of the assets acquired and liabilities assumed is recorded as goodwill. The results of operations of the acquired businesses are included in our condensed consolidated financial statements from the date of acquisition. Acquisition-related expenses are expensed as incurred.
Deferred Commissions	Deferred Commissions Deferred commissions consist of incremental costs paid to our sales force to obtain customer contracts. Deferred commissions related to product revenues are recognized upon transfer of control to customers and deferred commissions related to support subscription revenue are amortized over an expected useful life of six years. We determine the expected useful life based on an estimated benefit period by evaluating our technology development life cycle, expected customer relationship period, and other factors. We classify deferred commissions as current and non-current on our condensed consolidated balance sheets based on the timing of when we expect to recognize the expense. Amortization of deferred commissions is included in sales and marketing expense in the condensed consolidated statements of operations.
Revenue Recognition	Revenue Recognition We derive revenue from two sources: (1) product revenue which includes hardware and embedded software and (2) support subscription revenue which includes customer support, hardware maintenance, and software upgrades on a when-and-if-available basis. Our product revenue is derived from the sale of storage hardware and operating system software that is integrated into the hardware. We typically recognize product revenue upon transfer of control to our customers. Products are typically shipped directly by us to customers, and our channel partners do not stock our inventory. Our support subscription revenue is derived from the sale of support subscription, which includes the right to receive unspecified software upgrades and enhancements on a when-and-if-available basis, bug fixes, parts replacement services related to the hardware, as well as access to our cloud-based management and support platform. Revenue related to support subscription is recognized ratably over the contractual term, which generally ranges from one to six years and represents our performance obligations period. The vast majority of our products are sold with support subscription agreements, which typically commence upon transfer of control of the corresponding products to our customers. Costs to service the support subscription are expensed as incurred. In addition, our Evergreen Storage program provides our customers who continually maintain active support subscription agreements for three years with an included controller refresh with each additional three year support subscription renewal. In accordance with revenue recognition guidance, the controller refresh represents an additional performance obligation and the allocated revenue is recognized in the period in which these controllers are shipped. We recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration we expect to be entitled in exchange for those goods or services. This is achieved through applying the following five-step approach: • Identification of the contract, or contracts, with a customer • Identification of the performance obligations in the contract • Determination of the transaction price • Allocation of the transaction price to the performance obligations in the contract • Recognition of revenue when, or as, we satisfy a performance obligation When applying this five-step approach, we apply judgment in determining the customer's ability and intention to pay, which is based on a variety of factors including the customer's historical payment experience and/or published credit and financial information pertaining to the customer. To the extent a customer contract includes multiple promised goods or services, we determine whether promised goods or services are capable of being distinct in the context of the contract to be accounted for as a combined performance obligation. We allocate transaction price to each performance obligation for contracts that contain multiple performance obligations based on a relative standalone selling price, taking into account available information such as market conditions and internally approved pricing guidelines related to performance obligations. Deferred Revenue Deferred revenue primarily consists of amounts that have been invoiced but that have not yet been recognized as revenue and performance obligations pertaining to support subscription services. The current portion of deferred revenue represents the amounts that are expected to be recognized as revenue within one year of the condensed consolidated balance sheet dates.
Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB), issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09 or ASC 606), requiring an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASC 606 supersedes nearly all existing revenue recognition guidance under U.S. GAAP upon its effective date. The standard permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of applying the standard recognized at the date of application (cumulative catch-up transition method). We adopted the standard using the full retrospective method beginning February 1, 2018, for the year ending January 31, 2019, and our historical financial information for the years ended January 31, 2017 and 2018 has been adjusted to conform to the new standard. The most significant impact of the standard related to the removal of limitation on contingent revenue, resulting in an increase in product revenue and a decrease in support subscription revenue. In addition, the adoption of ASC 606 also resulted in differences in the timing of recognition of sales commissions. While the adoption of the standard changes certain line items within the net cash flow from operating activities, it had no impact on the net cash provided by or used in operating, investing, or financing activities on our condensed consolidated statements of cash flows. The following line items on our condensed consolidated balance sheet as of January 31, 2018 have been adjusted to reflect the adoption of ASC 606 (in thousands): As of January 31, 2018 As Previously Reported Adjustment As Adjusted Assets: Deferred commissions, current $ 22,437 $ (1,349 ) $ 21,088 Deferred commissions, non-current 20,288 45,937 66,225 Total deferred commissions $ 42,725 $ 44,588 $ 87,313 Liabilities: Deferred revenue, current $ 209,377 $ (18,148 ) $ 191,229 Deferred revenue, non-current 196,632 (13,759 ) 182,873 Total deferred revenue $ 406,009 $ (31,907 ) $ 374,102 Stockholders' equity: Accumulated deficit $ (980,082 ) $ 76,495 $ (903,587 ) The following line items on our unaudited condensed consolidated statement of operations for the three and nine months ended October 31, 2017 have been adjusted to reflect the adoption of ASC 606 (in thousands, except per share data): Three Months Ended October 31, 2017 Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted As Previously Reported Adjustment As Adjusted Revenue: Product $ 223,196 $ 4,576 $ 227,772 $ 536,634 $ 13,657 $ 550,291 Support subscription 54,478 (4,659 ) 49,819 148,132 (13,517 ) 134,615 Total revenue $ 277,674 $ (83 ) $ 277,591 $ 684,766 $ 140 $ 684,906 Gross profit $ 181,815 $ (83 ) $ 181,732 $ 448,908 $ 140 $ 449,048 Sales and marketing $ 129,299 $ (12,328 ) $ 116,971 $ 346,896 $ (20,610 ) $ 326,286 Total operating expenses $ 223,632 $ (12,328 ) $ 211,304 $ 618,276 $ (20,610 ) $ 597,666 Loss from operations $ (41,817 ) $ 12,245 $ (29,572 ) $ (169,368 ) $ 20,750 $ (148,618 ) Loss before provision for income taxes $ (40,679 ) $ 12,245 $ (28,434 ) $ (162,969 ) $ 20,750 $ (142,219 ) Net loss $ (41,649 ) $ 12,245 $ (29,404 ) $ (165,724 ) $ 20,750 $ (144,974 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.20 ) $ 0.06 $ (0.14 ) $ (0.79 ) $ 0.10 $ (0.69 ) Unaudited revenue by geographic location based on bill-to location, which reflects the adoption impact of ASC 606, are as follows (in thousands): Three Months Ended October 31, 2017 Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted As Previously Reported Adjustment As Adjusted Revenue: United States $ 192,977 $ (58 ) $ 192,919 $ 504,937 $ 108 $ 505,045 Rest of the world 84,697 (25 ) 84,672 179,829 32 179,861 Total revenue $ 277,674 $ (83 ) $ 277,591 $ 684,766 $ 140 $ 684,906 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18), which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and restricted cash. We adopted ASU 2016-18 effective February 1, 2018 on a retrospective basis. Upon adoption, restricted cash is included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The adoption of this standard increased our previously reported net cash flow from investing activities for the periods in which there were changes in restricted cash but did not impact our net cash flow from operating activities or financing activities presented on our consolidated statements of cash flows. The following line items in our unaudited condensed consolidated statement of cash flows for the nine months ended October 31, 2017 have been adjusted to reflect the adoption of ASU 2016-18 and ASC 606 (in thousands): Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted Net loss (1) $ (165,724 ) $ 20,750 $ (144,974 ) Adjustments to reconcile net loss to net cash provided by operating activities: Deferred commissions (1) $ (7,629 ) $ (6,340 ) $ (13,969 ) Accrued compensation and other liabilities (1) $ 14,629 $ (14,270 ) $ 359 Deferred revenue (1) $ 54,404 $ (140 ) $ 54,264 Cash provided by operating activities $ 13,756 $ — $ 13,756 Net increase in restricted cash (2) $ (2,029 ) $ 2,029 $ — Net cash used in investing activities (2) $ (53,290 ) $ 2,029 $ (51,261 ) Net increase (decrease) in cash, cash equivalents and restricted cash (2) $ (1,636 ) $ 2,029 $ 393 Cash, cash equivalents and restricted cash, beginning of period (2) $ 183,675 $ 12,734 $ 196,409 Cash, cash equivalents and restricted cash, end of period (2) $ 182,039 $ 14,763 $ 196,802 _____________________________________________________ (1) Adjustment pertaining to the adoption of ASC 606. (2) Adjustment pertaining to the adoption of ASU 2016-18. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718) (ASU 2018-07). ASU 2018-07 aligns the accounting for share-based awards to employees and non-employees to follow the same model. The new standard is effective for fiscal years beginning after December 15, 2018 using a modified retrospective transition approach. Early adoption is permitted. We adopted this standard for the three and nine months ended October 31, 2018 and the adoption of this standard did not materially impact our consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires lessees to recognize all leases with terms in excess of one year on their balance sheet as a right-of-use asset and a lease liability at the commencement date. The new standard also simplifies the accounting for sale and leaseback transactions. ASU 2016-02 requires the use of the modified retrospective method for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In July 2018, the FASB issued ASU No. 2018-10, Leases (Topic 842), Codification Improvements to Topic 842, Leases (ASU 2018-10) and ASU No. 2018-11, Leases (Topic 842), Targeted Improvements (ASU 2018-11). ASU 2018-11 provides a new transition method in which an entity can initially apply the new lease standards at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. These standards will be effective for us beginning on February 1, 2019 and early adoption is permitted. We expect to apply the new transition method prescribed by ASU 2018-11 at the adoption date. We are currently evaluating the impact of these standards on our consolidated financial statements and expect that most of our operating lease commitments will be subject to the new standard and recognized as lease liabilities and right-of-use assets, which will increase our total assets and total liabilities upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 amends guidance on reporting credit losses for assets held at amortized cost basis and available-for-sale debt securities to require that credit losses on available-for-sale debt securities be presented as an allowance rather than as a write-down. The measurement of credit losses for newly recognized financial assets and subsequent changes in the allowance for credit losses are recorded in the statements of operations. The amendments in this update will be effective for us beginning on February 1, 2020 with early adoption permitted on or after February 1, 2019. We are currently evaluating the impact of this standard on our consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350) : Simplifying the Test for Goodwill Impairment , which eliminates Step 2 from the goodwill impairment test. This standard is effective, on a prospective basis, for our goodwill impairment tests beginning February 1, 2020. Early adoption is permitted. We are evaluating the impact of this standard on our consolidated financial statements. In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This standard allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act) and requires certain disclosures about stranded tax effects. This standard will be effective for us beginning February 1, 2019 and should be applied either in the period of adoption or retrospectively. Early adoption is permitted. We do not expect this standard to have any impact on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (ASU 2018-13) which amended its conceptual framework to improve the effectiveness of disclosures in notes to financial statements. ASU 2018-13 eliminates such disclosures around the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. The guidance also adds new disclosure requirements for Level 3 measurements. ASU 2018-13 is effective for us beginning February 1, 2020. Early adoption is permitted. We are currently evaluating the impact of this standard on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). ASC 2018-15 aligns the requirements for capitalizing implementation costs in a cloud computing arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This standard will be effective for us beginning February 1, 2020 and should be applied either retrospectively or prospectively. Early adoption is permitted. We are currently evaluating the impact of this standard on our consolidated financial statements. In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification , amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. This final rule was effective on November 5, 2018. We are evaluating the impact of this guidance on our condensed consolidated financial statements and expect to adopt this guidance in the first quarter of fiscal 2020.
Fair Value Measurements	Fair Value Measurements We measure our cash equivalents, marketable securities, and restricted cash at fair value on a recurring basis. We define fair value as the exchange price that would be received from sale of an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. We measure our financial assets and liabilities at fair value at each reporting period using a fair value hierarchy which requires us to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s classification within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs may be used to measure fair value: • Level 1 - Observable inputs are unadjusted quoted prices in active markets for identical assets or liabilities; • Level 2 - Observable inputs are quoted prices for similar assets and liabilities in active markets or inputs other than quoted prices that are observable for the assets or liabilities, either directly or indirectly through market corroboration, for substantially the full term of the financial instruments; and • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. These inputs are based on our own assumptions used to measure assets and liabilities at fair value and require significant management judgment or estimation. We classify our cash equivalents, marketable securities and restricted cash within Level 1 or Level 2 because they are valued using either quoted market prices or inputs other than quoted prices which are directly or indirectly observable in the market, including readily-available pricing sources for the identical underlying security which may not be actively traded. Our fixed income available-for-sale securities consist of high quality, investment grade securities from diverse issuers. The valuation techniques used to measure the fair value of our marketable securities were derived from non-binding market consensus prices that are corroborated by observable market data or quoted market prices for similar instruments. In addition to our cash equivalents, marketable securities, and restricted cash, we measure the fair value of our convertible senior notes (the Notes) on a quarterly basis for disclosure purposes. We consider the fair value of the Notes at October 31, 2018 to be a Level 2 measurement due to limited trading activity of the Notes. Refer to Note 6 for further information.

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Oct. 31, 2018
Accounting Policies [Abstract]
Deferred Commissions	Changes in total deferred commissions during the periods presented are as follows (in thousands): Three Months Ended October 31, 2018 Nine Months Ended October 31, 2018 Beginning balance (1) $ 91,469 $ 87,313 Additions 31,884 71,887 Recognition of deferred commissions (26,913 ) (62,760 ) Ending balance as of October 31, 2018 $ 96,440 $ 96,440 ____________________ (1) Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606.
Deferred Revenue	Changes in total deferred revenue during the periods presented are as follows (in thousands): Three Months Ended October 31, 2018 Nine Months Ended October 31, 2018 Beginning balance (1) $ 413,247 $ 374,102 Additions 122,681 290,463 Recognition of deferred revenue (74,740 ) (203,377 ) Ending balance as of October 31, 2018 $ 461,188 $ 461,188 ____________________ (1) Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606.
Schedule of Recently Adopted Accounting Pronouncements	The following line items on our condensed consolidated balance sheet as of January 31, 2018 have been adjusted to reflect the adoption of ASC 606 (in thousands): As of January 31, 2018 As Previously Reported Adjustment As Adjusted Assets: Deferred commissions, current $ 22,437 $ (1,349 ) $ 21,088 Deferred commissions, non-current 20,288 45,937 66,225 Total deferred commissions $ 42,725 $ 44,588 $ 87,313 Liabilities: Deferred revenue, current $ 209,377 $ (18,148 ) $ 191,229 Deferred revenue, non-current 196,632 (13,759 ) 182,873 Total deferred revenue $ 406,009 $ (31,907 ) $ 374,102 Stockholders' equity: Accumulated deficit $ (980,082 ) $ 76,495 $ (903,587 ) The following line items on our unaudited condensed consolidated statement of operations for the three and nine months ended October 31, 2017 have been adjusted to reflect the adoption of ASC 606 (in thousands, except per share data): Three Months Ended October 31, 2017 Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted As Previously Reported Adjustment As Adjusted Revenue: Product $ 223,196 $ 4,576 $ 227,772 $ 536,634 $ 13,657 $ 550,291 Support subscription 54,478 (4,659 ) 49,819 148,132 (13,517 ) 134,615 Total revenue $ 277,674 $ (83 ) $ 277,591 $ 684,766 $ 140 $ 684,906 Gross profit $ 181,815 $ (83 ) $ 181,732 $ 448,908 $ 140 $ 449,048 Sales and marketing $ 129,299 $ (12,328 ) $ 116,971 $ 346,896 $ (20,610 ) $ 326,286 Total operating expenses $ 223,632 $ (12,328 ) $ 211,304 $ 618,276 $ (20,610 ) $ 597,666 Loss from operations $ (41,817 ) $ 12,245 $ (29,572 ) $ (169,368 ) $ 20,750 $ (148,618 ) Loss before provision for income taxes $ (40,679 ) $ 12,245 $ (28,434 ) $ (162,969 ) $ 20,750 $ (142,219 ) Net loss $ (41,649 ) $ 12,245 $ (29,404 ) $ (165,724 ) $ 20,750 $ (144,974 ) Net loss per share attributable to common stockholders, basic and diluted $ (0.20 ) $ 0.06 $ (0.14 ) $ (0.79 ) $ 0.10 $ (0.69 ) Unaudited revenue by geographic location based on bill-to location, which reflects the adoption impact of ASC 606, are as follows (in thousands): Three Months Ended October 31, 2017 Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted As Previously Reported Adjustment As Adjusted Revenue: United States $ 192,977 $ (58 ) $ 192,919 $ 504,937 $ 108 $ 505,045 Rest of the world 84,697 (25 ) 84,672 179,829 32 179,861 Total revenue $ 277,674 $ (83 ) $ 277,591 $ 684,766 $ 140 $ 684,906 The following line items in our unaudited condensed consolidated statement of cash flows for the nine months ended October 31, 2017 have been adjusted to reflect the adoption of ASU 2016-18 and ASC 606 (in thousands): Nine Months Ended October 31, 2017 As Previously Reported Adjustment As Adjusted Net loss (1) $ (165,724 ) $ 20,750 $ (144,974 ) Adjustments to reconcile net loss to net cash provided by operating activities: Deferred commissions (1) $ (7,629 ) $ (6,340 ) $ (13,969 ) Accrued compensation and other liabilities (1) $ 14,629 $ (14,270 ) $ 359 Deferred revenue (1) $ 54,404 $ (140 ) $ 54,264 Cash provided by operating activities $ 13,756 $ — $ 13,756 Net increase in restricted cash (2) $ (2,029 ) $ 2,029 $ — Net cash used in investing activities (2) $ (53,290 ) $ 2,029 $ (51,261 ) Net increase (decrease) in cash, cash equivalents and restricted cash (2) $ (1,636 ) $ 2,029 $ 393 Cash, cash equivalents and restricted cash, beginning of period (2) $ 183,675 $ 12,734 $ 196,409 Cash, cash equivalents and restricted cash, end of period (2) $ 182,039 $ 14,763 $ 196,802 _____________________________________________________ (1) Adjustment pertaining to the adoption of ASC 606. (2) Adjustment pertaining to the adoption of ASU 2016-18.

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Oct. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Cash Equivalents, Marketable Securities and Restricted Cash by Significant Investment Categories	The following tables summarize our cash equivalents, marketable securities and restricted cash by significant investment categories as of January 31, 2018 and October 31, 2018 (in thousands): As of January 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash Equivalents Marketable Securities Restricted Cash Level 1 Money market accounts $ — $ — $ — $ 32,057 $ 17,294 $ — $ 14,763 Level 2 U.S. government treasury notes 131,643 — (651 ) 130,992 10,172 120,820 — U.S. government agencies 47,229 — (333 ) 46,896 — 46,896 — Corporate debt securities 186,506 116 (1,049 ) 185,573 — 185,573 — Total $ 365,378 $ 116 $ (2,033 ) $ 395,518 $ 27,466 $ 353,289 $ 14,763 As of October 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash Equivalents Marketable Securities Restricted Cash Level 1 Money market accounts $ — $ — $ — $ 26,298 $ 10,476 $ — $ 15,822 Level 2 U.S. government treasury notes 323,212 — (891 ) 322,321 62,392 259,929 — U.S. government agencies 73,362 — (355 ) 73,007 2,992 70,015 — Corporate debt securities 377,468 31 (1,830 ) 375,669 — 375,669 — Foreign government bonds 6,657 1 (14 ) 6,644 — 6,644 — Asset-backed securities 24,804 — (41 ) 24,763 — 24,763 — Total $ 805,503 $ 32 $ (3,131 ) $ 828,702 $ 75,860 $ 737,020 $ 15,822
Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity	The amortized cost and estimated fair value of our marketable securities are shown below by contractual maturity (in thousands): As of October 31, 2018 Amortized Cost Fair Value Due within one year $ 367,860 $ 366,886 Due in one to five years 372,255 370,134 Total $ 740,115 $ 737,020
Schedule of Gross Unrealized Losses and Fair Values for Investments that were in Continuous Unrealized Loss Position for Less Than 12 Months, Aggregated by Investments Category	The following table presents gross unrealized losses and fair values for those investments that were in a continuous unrealized loss position as of October 31, 2018 , aggregated by investment category (in thousands): Less than 12 months Greater than 12 months Total Fair Value Unrealized Loss Fair Unrealized Fair Unrealized U.S. government treasury notes $ 282,905 $ (535 ) $ 39,416 $ (356 ) $ 322,321 $ (891 ) U.S. government agencies 47,927 (143 ) 25,080 (212 ) 73,007 (355 ) Corporate debt securities 270,140 (1,080 ) 72,743 (750 ) 342,883 (1,830 ) Foreign government bonds 5,145 (14 ) — — 5,145 (14 ) Asset-backed securities 24,763 (41 ) — — 24,763 (41 ) Total $ 630,880 $ (1,813 ) $ 137,239 $ (1,318 ) $ 768,119 $ (3,131 )

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Oct. 31, 2018
Balance Sheet Components Disclosure [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands): As of As of Raw materials $ 1,181 $ 4,880 Finished goods 33,316 45,857 Inventory $ 34,497 $ 50,737
Schedule of Property and Equipment, Net	Property and equipment, net, consists of the following (in thousands): As of As of Test equipment $ 142,311 $ 166,936 Computer equipment and software 72,329 103,366 Furniture and fixtures 5,363 5,619 Leasehold improvements 15,032 31,707 Total property and equipment 235,035 307,628 Less: accumulated depreciation and amortization (145,893 ) (192,362 ) Property and equipment, net $ 89,142 $ 115,266
Schedule of Intangible Assets, Net	Intangible assets, net consist of the following (in thousands): As of As of Gross Carrying Value Accumulated Amortization Net Carrying Amount Gross Carrying Value Accumulated Amortization Net Carrying Amount Technology patents $ 10,125 $ (5,068 ) $ 5,057 $ 10,125 $ (6,196 ) $ 3,929 Developed technology — — — 17,700 (503 ) 17,197 Intangible assets, net $ 10,125 $ (5,068 ) $ 5,057 $ 27,825 $ (6,699 ) $ 21,126
Schedule of Expected Amortization Expenses for Intangible Assets	As of October 31, 2018 , future expected amortization expense for intangible assets is as follows (in thousands): Fiscal Years Ending January 31, Estimated Future Amortization Expense Remainder of 2019 $ 1,008 2020 4,032 2021 4,032 2022 3,074 2023 2,529 Thereafter 6,451 Total $ 21,126
Schedule of Goodwill	The change in the carrying amount of goodwill is as follows (in thousands): Amount Balance as of January 31, 2018 $ — Goodwill acquired 10,997 Balance as of October 31, 2018 $ 10,997
Schedule of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consist of the following (in thousands): As of As of Taxes payable $ 4,052 $ 6,907 Accrued marketing 5,928 8,561 Accrued travel and entertainment expenses 4,386 4,108 Acquisition consideration held back — 3,725 Other accrued liabilities 12,463 20,332 Total accrued expenses and other liabilities $ 26,829 $ 43,633

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	9 Months Ended
	Oct. 31, 2018
Debt Disclosure [Abstract]
Convertible Debt	The Notes consisted of the following (in thousands): As of Liability: Principal $ 575,000 Less: debt discount, net of amortization (122,891 ) Less: debt issuance costs, net of amortization (8,897 ) Net carrying amount of the Notes $ 443,212 Stockholders' equity: Allocated value of the conversion feature $ 136,333 Less: debt issuance costs (3,068 ) Additional paid-in capital $ 133,265
Interest Expense	The following table sets forth total interest expense recognized related to the Notes for the three and nine months ended October 31, 2018 (in thousands): Three Months Ended October 31, 2018 Nine Months Ended October 31, 2018 Amortization of debt discount $ 6,084 $ 13,441 Amortization of debt issuance costs 441 973 Total amortization of debt discount and debt issuance costs 6,525 14,414 Contractual interest expense 181 405 Total interest expense related to the Notes $ 6,706 $ 14,819 Effective interest rate of the liability component 5.6 % 5.6 %

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	9 Months Ended
	Oct. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity Under Equity Incentive Plans and Related Information	A summary of stock option activity under our equity incentive plans and related information is as follows: Options Outstanding Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (In Years) Aggregate Intrinsic Value (in thousands) Balance as of January 31, 2018 46,359,949 $ 7.75 6.3 $ 574,224 Options exercised (8,249,893 ) 5.26 Options forfeited/canceled (1,360,202 ) 10.04 Balance as of October 31, 2018 36,749,854 $ 8.22 5.6 $ 439,185 Vested and exercisable as of October 31, 2018 26,221,996 $ 6.38 5.2 $ 361,783
Summary of Restricted Stock Unit Activity Under 2015 Plan	A summary of the restricted stock unit activity under our 2015 Plan and related information is as follows: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Aggregate Unvested balance as of January 31, 2018 17,682,646 $ 12.60 $ 356,117 Granted 11,098,371 22.49 Vested (6,429,146 ) 12.84 Forfeited (1,719,729 ) 15.57 Converted (1,142,838 ) 11.86 Unvested balance as of October 31, 2018 19,489,304 $ 17.92 $ 393,270
Summary of Restricted Stock Activity Under 2015 Plan	A summary of the restricted stock activity under our 2015 Plan and related information is as follows: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Aggregate Unvested balance as of January 31, 2018 — $ — $ — Granted and converted 3,330,118 19.25 Vested (116,186 ) 12.84 Unvested balance as of October 31, 2018 3,213,932 $ 19.49 $ 64,857
Summarizes the Components of Stock-Based Compensation	The following table summarizes the components of stock-based compensation expense recognized in the condensed consolidated statements of operations (in thousands): Three Months Ended Nine Months Ended 2017 2018 2017 2018 Cost of revenue—product $ 143 $ 862 $ 898 $ 2,190 Cost of revenue—support subscription 2,422 3,327 6,441 8,940 Research and development 18,073 24,634 51,632 67,956 Sales and marketing 12,104 18,681 34,169 49,890 General and administrative 6,121 10,825 14,780 26,962 Total stock-based compensation expense $ 38,863 $ 58,329 $ 107,920 $ 155,938

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Oct. 31, 2018
Earnings Per Share [Abstract]
Summary of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except per share data): Three Months Ended Nine Months Ended 2017 2018 2017 2018 (As Adjusted*) (As Adjusted*) Net loss $ (29,404 ) $ (28,180 ) $ (144,974 ) $ (152,607 ) Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 213,274 235,205 209,456 229,505 Net loss per share attributable to common stockholders, basic and diluted $ (0.14 ) $ (0.12 ) $ (0.69 ) $ (0.66 ) * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.
Summary of Weighted-average Outstanding Shares Excluded from Computation of Diluted Net Loss per Share Attributable to Common Stockholders	The following weighted-average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive (in thousands): Three Months Ended Nine Months Ended 2017 2018 2017 2018 Stock options to purchase common stock 51,685 37,814 53,786 41,201 Restricted stock units 17,201 19,493 14,913 19,488 Restricted stock and early exercised stock options 196 3,277 287 2,938 Employee stock purchase plan 585 236 585 80 Total 69,667 60,820 69,571 63,707

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Oct. 31, 2018
Segment Reporting [Abstract]
Schedule of Revenue by Geographic Area	The following table depicts the disaggregation of revenue by geographic area based on the billing address of our customers and is consistent with how we evaluate our financial performance (in thousands): Three Months Ended Nine Months Ended 2017 2018 2017 2018 (As Adjusted*) (As Adjusted*) United States $ 192,919 $ 263,488 $ 505,045 $ 678,166 Rest of the world 84,672 109,291 179,861 259,442 Total revenue $ 277,591 $ 372,779 $ 684,906 $ 937,608 * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.
Schedule of Long-Lived Assets by Geographic Area	Long-lived assets by geographic area are summarized as follows (in thousands): As of As of United States $ 85,430 $ 110,850 Rest of the world 3,712 4,416 Total long-lived assets $ 89,142 $ 115,266

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018		Oct. 31, 2017
Accounting Policies [Abstract]
Restricted cash	$ 15,822	$ 14,763	[1]	$ 14,763	[2]
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.
[2]	* 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

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Deferred Commissions (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Accounting Policies [Abstract]
Remaining amortization period	6 years		6 years
Contract Assets
Beginning balance	$ 91,469,000		$ 87,313,000
Additions	31,884,000		71,887,000
Recognition of deferred commissions	(26,913,000)		(62,760,000)
Ending balance as of October 31, 2018	96,440,000		96,440,000
Impairment loss, capitalized commissions	$ 0	$ 0	$ 0	$ 0

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Deferred Commissions (Typed Dimensions) (Details) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-08-01	9 Months Ended
	Oct. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percentage	25.00%
Remaining performance obligation, expected timing	1 year

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Contract Liability
Beginning balance	$ 413,247		$ 374,102
Additions	122,681		290,463
Recognition of deferred revenue	74,740		203,377
Ending balance as of October 31, 2018	461,188		461,188
Product Revenue and Support Subscription Revenue
Contract Liability
Deferred revenue recognized	$ 67,000	$ 47,300	$ 151,400	$ 108,200

Basis of Presentation and Sum_8

Basis of Presentation and Summary of Significant Accounting Policies - Deferred Revenue (Typed Dimensions) (Details) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-08-01	Oct. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percentage	50.00%
Remaining performance obligation, expected timing	1 year

Basis of Presentation and Sum_9

Basis of Presentation and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Balance Sheet) (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jul. 31, 2018	Jan. 31, 2018
Assets:
Deferred commissions, current	$ 24,100		$ 21,088	[1]
Deferred commissions, non-current	72,340		66,225	[1]
Total deferred commissions	96,440	$ 91,469	87,313
Liabilities:
Deferred revenue, current	232,570		191,229	[1]
Deferred revenue, non-current	228,618		182,873	[1]
Total deferred revenue	461,188	$ 413,247	374,102
Stockholders' equity:
Accumulated deficit	$ (1,056,194)		(903,587)	[1]
As Previously Reported
Assets:
Deferred commissions, current			22,437
Deferred commissions, non-current			20,288
Total deferred commissions			42,725
Liabilities:
Deferred revenue, current			209,377
Deferred revenue, non-current			196,632
Total deferred revenue			406,009
Stockholders' equity:
Accumulated deficit			(980,082)
Adjustment | Accounting Standards Update 2014-09
Assets:
Deferred commissions, current			(1,349)
Deferred commissions, non-current			45,937
Total deferred commissions			44,588
Liabilities:
Deferred revenue, current			(18,148)
Deferred revenue, non-current			(13,759)
Total deferred revenue			(31,907)
Stockholders' equity:
Accumulated deficit			$ 76,495
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Basis of Presentation and Su_10

Basis of Presentation and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Statement of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017		Oct. 31, 2018	Oct. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 372,779	$ 277,591	[1]	$ 937,608	$ 684,906	[1]
Gross profit	249,120	181,732	[1]	621,600	449,048	[1]
Sales and marketing	146,903	116,971	[1]	413,019	326,286	[1]
Total operating expenses	276,337	211,304	[1]	765,897	597,666	[1]
Loss from operations	(27,217)	(29,572)	[1]	(144,297)	(148,618)	[1]
Loss before provision for income taxes	(30,106)	(28,434)	[1]	(152,217)	(142,219)	[1]
Net loss	$ (28,180)	$ (29,404)	[1],[2]	$ (152,607)	$ (144,974)	[1],[2],[3]
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.12)	$ (0.14)	[1]	$ (0.66)	$ (0.69)	[1]
Product
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 298,863	$ 227,772	[1]	$ 735,449	$ 550,291	[1]
Support subscription
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 73,916	49,819	[1]	$ 202,159	134,615	[1]
Adjustment | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		(83)			140
Gross profit		(83)			140
Sales and marketing		(12,328)			(20,610)
Total operating expenses		(12,328)			(20,610)
Loss from operations		12,245			20,750
Loss before provision for income taxes		12,245			20,750
Net loss		$ 12,245			$ 20,750
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)		$ 0.06			$ 0.10
Adjustment | Product | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ 4,576			$ 13,657
Adjustment | Support subscription | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		(4,659)			(13,517)
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		277,674			684,766
Gross profit		181,815			448,908
Sales and marketing		129,299			346,896
Total operating expenses		223,632			618,276
Loss from operations		(41,817)			(169,368)
Loss before provision for income taxes		(40,679)			(162,969)
Net loss		$ (41,649)			$ (165,724)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)		$ (0.20)			$ (0.79)
As Previously Reported | Product
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ 223,196			$ 536,634
As Previously Reported | Support subscription
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ 54,478			$ 148,132
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, 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 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

Basis of Presentation and Su_11

Basis of Presentation and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017		Oct. 31, 2018	Oct. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 372,779	$ 277,591	[1]	$ 937,608	$ 684,906	[1]
United States
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	263,488	192,919		678,166	505,045
Rest of the world
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 109,291	84,672		$ 259,442	179,861
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		277,674			684,766
As Previously Reported | United States
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		192,977			504,937
As Previously Reported | Rest of the world
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		84,697			179,829
Adjustment | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		(83)			140
Adjustment | United States | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		(58)			108
Adjustment | Rest of the world | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ (25)			$ 32
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.

Basis of Presentation and Su_12

Basis of Presentation and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Statement of Cash Flows) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Oct. 31, 2018	Oct. 31, 2017		Oct. 31, 2018	Oct. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss		$ (28,180)	$ (29,404)	[1],[2]	$ (152,607)	$ (144,974)	[1],[2],[3]
Adjustments to reconcile net loss to net cash provided by operating activities:
Deferred commissions					(9,127)	(13,969)	[3]
Accrued compensation and other liabilities					7,592	359	[3]
Deferred revenue					87,005	54,264	[3]
Cash provided by operating activities					83,629	13,756	[3]
Net increase in restricted cash	[3]					0
Net cash used in investing activities					(468,103)	(51,261)	[3]
Net increase (decrease) in cash, cash equivalents and restricted cash					163,643	393	[3]
Cash, cash equivalents and restricted cash, beginning of period					258,820	196,409	[3]
Cash, cash equivalents and restricted cash, end of period		$ 422,463	196,802	[3]	$ 422,463	196,802	[3]
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss			(41,649)			(165,724)
Adjustments to reconcile net loss to net cash provided by operating activities:
Deferred commissions						(7,629)
Accrued compensation and other liabilities						14,629
Deferred revenue						54,404
Cash provided by operating activities						13,756
Net increase in restricted cash						(2,029)
Net cash used in investing activities						(53,290)
Net increase (decrease) in cash, cash equivalents and restricted cash						(1,636)
Cash, cash equivalents and restricted cash, beginning of period						183,675
Cash, cash equivalents and restricted cash, end of period			182,039			182,039
Adjustment | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss			12,245			20,750
Adjustments to reconcile net loss to net cash provided by operating activities:
Deferred commissions						(6,340)
Accrued compensation and other liabilities						(14,270)
Deferred revenue						(140)
Cash provided by operating activities						0
Adjustment | Accounting Standards Update 2016-18
Adjustments to reconcile net loss to net cash provided by operating activities:
Net increase in restricted cash						2,029
Net cash used in investing activities						2,029
Net increase (decrease) in cash, cash equivalents and restricted cash						2,029
Cash, cash equivalents and restricted cash, beginning of period						12,734
Cash, cash equivalents and restricted cash, end of period			$ 14,763			$ 14,763
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, 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 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

Financial Instruments - Summary

Financial Instruments - Summary of Cash Equivalents, Marketable Securities and Restricted Cash by Significant Investment Categories (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 805,503	$ 365,378
Gross Unrealized Gains	32	116
Gross Unrealized Losses	(3,131)	(2,033)
Fair Value	828,702	395,518
Cash Equivalents	75,860	27,466
Marketable Securities	737,020	353,289
Restricted Cash	15,822	14,763
Level 1 | Money market accounts
Debt Securities, Available-for-sale [Line Items]
Fair Value	26,298	32,057
Cash Equivalents	10,476	17,294
Marketable Securities	0	0
Restricted Cash	15,822	14,763
Level 2 | U.S. government treasury notes
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	323,212	131,643
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(891)	(651)
Fair Value	322,321	130,992
Cash Equivalents	62,392	10,172
Marketable Securities	259,929	120,820
Restricted Cash	0	0
Level 2 | U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	73,362	47,229
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(355)	(333)
Fair Value	73,007	46,896
Cash Equivalents	2,992	0
Marketable Securities	70,015	46,896
Restricted Cash	0	0
Level 2 | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	377,468	186,506
Gross Unrealized Gains	31	116
Gross Unrealized Losses	(1,830)	(1,049)
Fair Value	375,669	185,573
Cash Equivalents	0	0
Marketable Securities	375,669	185,573
Restricted Cash	0	$ 0
Level 2 | Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	6,657
Gross Unrealized Gains	1
Gross Unrealized Losses	(14)
Fair Value	6,644
Cash Equivalents	0
Marketable Securities	6,644
Restricted Cash	0
Level 2 | Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	24,804
Gross Unrealized Gains	0
Gross Unrealized Losses	(41)
Fair Value	24,763
Cash Equivalents	0
Marketable Securities	24,763
Restricted Cash	$ 0

Financial Instruments - Schedul

Financial Instruments - Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity (Details) $ in Thousands	Oct. 31, 2018USD ($)
Investments, Debt and Equity Securities [Abstract]
Due within one year, Amortized Cost	$ 367,860
Due in one to five years, Amortized Cost	372,255
Amortized Cost	740,115
Due within one year, Fair Value	366,886
Due in one to five years, Fair Value	370,134
Fair Value	$ 737,020

Financial Instruments - Sched_2

Financial Instruments - Schedule of Gross Unrealized Losses and Fair Values for Investments that were in Continuous Unrealized Loss Position for Less Than 12 Months, Aggregated by Investments Category (Details) $ in Thousands	Oct. 31, 2018USD ($)
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	$ 630,880
Unrealized Loss, Less than 12 Months	(1,813)
Fair Value, Greater than 12 months	137,239
Unrealized Loss, Greater than 12 months	(1,318)
Fair Value, Total	768,119
Unrealized Loss, Total	(3,131)
U.S. government treasury notes
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	282,905
Unrealized Loss, Less than 12 Months	(535)
Fair Value, Greater than 12 months	39,416
Unrealized Loss, Greater than 12 months	(356)
Fair Value, Total	322,321
Unrealized Loss, Total	(891)
U.S. government agencies
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	47,927
Unrealized Loss, Less than 12 Months	(143)
Fair Value, Greater than 12 months	25,080
Unrealized Loss, Greater than 12 months	(212)
Fair Value, Total	73,007
Unrealized Loss, Total	(355)
Corporate debt securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	270,140
Unrealized Loss, Less than 12 Months	(1,080)
Fair Value, Greater than 12 months	72,743
Unrealized Loss, Greater than 12 months	(750)
Fair Value, Total	342,883
Unrealized Loss, Total	(1,830)
Foreign government bonds
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	5,145
Unrealized Loss, Less than 12 Months	(14)
Fair Value, Greater than 12 months	0
Unrealized Loss, Greater than 12 months	0
Fair Value, Total	5,145
Unrealized Loss, Total	(14)
Asset-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	24,763
Unrealized Loss, Less than 12 Months	(41)
Fair Value, Greater than 12 months	0
Unrealized Loss, Greater than 12 months	0
Fair Value, Total	24,763
Unrealized Loss, Total	$ (41)

Business Combination (Details)

Business Combination (Details) - USD ($) $ in Thousands	1 Months Ended
	Aug. 31, 2018	Oct. 31, 2018	Jan. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 10,997	$ 0	[1]
Acquisition consideration held back		$ 3,725	$ 0
StorReduce, Inc.
Business Acquisition [Line Items]
Cash consideration transferred	$ 20,500
Long-term debt assumed and subsequently paid off	6,100
Fees assumed associated with the transaction	1,100
Goodwill	11,000
Net liabilities assumed	4,500
Deferred tax liabilities assumed	3,700
Acquisition consideration held back	$ 3,725
StorReduce, Inc. | Restricted Stock Units
Business Acquisition [Line Items]
Equity interests issued and issuable, shares issued (in shares)	622,482
Equity interests issued and issuable	$ 13,600
StorReduce, Inc. | Developed technology
Business Acquisition [Line Items]
Finite-lived intangibles acquired	$ 17,700
Finite-lived intangibles acquired, amortization period	7 years
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventory (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Balance Sheet Components Disclosure [Abstract]
Raw materials	$ 4,880	$ 1,181
Finished goods	45,857	33,316
Inventory	$ 50,737	$ 34,497

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment	$ 307,628	$ 235,035
Less: accumulated depreciation and amortization	(192,362)	(145,893)
Property and equipment, net	115,266	89,142	[1]
Test equipment
Property Plant And Equipment [Line Items]
Total property and equipment	166,936	142,311
Computer equipment and software
Property Plant And Equipment [Line Items]
Total property and equipment	103,366	72,329
Furniture and fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	5,619	5,363
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 31,707	$ 15,032
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Balance Sheet Components Disclosure [Abstract]
Depreciation and amortization	$ 16.9	$ 15.2	$ 49.8	$ 44.4
Intangible assets amortization expense	$ 0.9	$ 0.4	$ 1.6	$ 1.1
Technology patents
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining useful life			2 years 7 months 6 days
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining useful life			6 years 9 months 18 days

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 27,825	$ 10,125
Accumulated Amortization	(6,699)	(5,068)
Net Carrying Amount	21,126	5,057	[1]
Technology patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	10,125	10,125
Accumulated Amortization	(6,196)	(5,068)
Net Carrying Amount	3,929	5,057
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	17,700	0
Accumulated Amortization	(503)	0
Net Carrying Amount	$ 17,197	$ 0
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Expected Amortization Expenses for Intangible Assets (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018	[1]
Balance Sheet Components Disclosure [Abstract]
Remainder of 2019	$ 1,008
2,020	4,032
2,021	4,032
2,022	3,074
2,023	2,529
Thereafter	6,451
Net Carrying Amount	$ 21,126	$ 5,057
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Goodwill (Details) $ in Thousands	9 Months Ended
	Oct. 31, 2018USD ($)
Goodwill [Roll Forward]
Balance as of January 31, 2018	$ 0	[1]
Goodwill acquired	10,997
Balance as of October 31, 2018	$ 10,997
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Balance Sheet Components Disclosure [Abstract]
Taxes payable	$ 6,907	$ 4,052
Accrued marketing	8,561	5,928
Accrued travel and entertainment expenses	4,108	4,386
Acquisition consideration held back	3,725	0
Other accrued liabilities	20,332	12,463
Total accrued expenses and other liabilities	$ 43,633	$ 26,829	[1]
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Convertible Senior Notes (Detai

Convertible Senior Notes (Details)	1 Months Ended	9 Months Ended
	Apr. 30, 2018USD ($)dayshares$ / shares	Oct. 31, 2018USD ($)$ / shares	Oct. 31, 2017USD ($)	[1]	Apr. 04, 2018$ / shares
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes, net of issuance costs		$ 562,062,000	$ 0
Debt issuance costs, net of amortization	$ 12,900,000
Closing price of stock (in dollars per share) | $ / shares		$ 20.18
Payment to enter into agreement		$ 64,630,000	$ 0
Capped Call
Debt Instrument [Line Items]
Payment to enter into agreement	64,600,000
Convertible Senior Notes
Debt Instrument [Line Items]
Debt issuance costs, net of amortization	9,800,000	8,897,000
Additional Paid-in Capital
Debt Instrument [Line Items]
Debt issuance costs, net of amortization	$ 3,100,000	$ 3,068,000
Class A
Debt Instrument [Line Items]
Closing price of stock (in dollars per share) | $ / shares		$ 20.18			$ 19.83
Class A | Capped Call
Debt Instrument [Line Items]
Exercise price (in dollars per share) | $ / shares	$ 39.66
Exercise price premium percentage over last reported sales price					100.00%
Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount	$ 575,000,000
Interest rate	0.125%
Proceeds from issuance of convertible senior notes, net of issuance costs	$ 562,100,000
Conversion percentage of principal amount plus accrued and unpaid contingent interest	100.00%
Convertible debt, fair value based on the closing trading price per $100 of the Notes		$ 586,500,000
If-converted value		$ 441,600,000
Convertible Senior Notes | Class A
Debt Instrument [Line Items]
Number of convertible shares at initial conversion rate (in shares) | shares	21,884,155
Conversion ratio (in shares per $1,000 principal amount)	38.0594
Conversion price (in dollars per share) | $ / shares	$ 26.27
Redemption percentage of principal amount of Notes to be redeemed	100.00%
Convertible Senior Notes | Class A | Any Fiscal Quarter Commencing After the Fiscal Quarter Ending on July 31, 2018
Debt Instrument [Line Items]
Threshold trading days | day	20
Threshold consecutive trading days | day	30
Threshold percentage of stock price trigger	130.00%
Convertible Senior Notes | Class A | Five Business Day Period After any Five Consecutive Trading Day Period
Debt Instrument [Line Items]
Threshold consecutive trading days | day	5
Threshold percentage of stock price trigger	98.00%
Threshold business days | day	5
Convertible Senior Notes | Class A | Immediately Preceding the Date on Which We Provide Notice of Redemption
Debt Instrument [Line Items]
Threshold trading days | day	2
[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

Convertible Senior Notes - Allo

Convertible Senior Notes - Allocation of Notes (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Apr. 30, 2018
Liability:
Less: debt issuance costs, net of amortization		$ (12,900)
Stockholders' equity:
Less: debt issuance costs		(12,900)
Convertible Senior Notes
Liability:
Principal	$ 575,000
Less: debt discount, net of amortization	(122,891)
Less: debt issuance costs, net of amortization	(8,897)	(9,800)
Net carrying amount of the Notes	443,212
Stockholders' equity:
Less: debt issuance costs	(8,897)	(9,800)
Additional Paid-in Capital
Liability:
Less: debt issuance costs, net of amortization	(3,068)	(3,100)
Stockholders' equity:
Allocated value of the conversion feature	136,333
Less: debt issuance costs	(3,068)	$ (3,100)
Additional paid-in capital	$ 133,265

Convertible Senior Notes - Inte

Convertible Senior Notes - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Oct. 31, 2018	Oct. 31, 2018	Oct. 31, 2017	[1]
Debt Instrument [Line Items]
Total amortization of debt discount and debt issuance costs		$ 14,414	$ 0
Convertible Senior Notes
Debt Instrument [Line Items]
Amortization of debt discount	$ 6,084	13,441
Amortization of debt issuance costs	441	973
Total amortization of debt discount and debt issuance costs	6,525	14,414
Contractual interest expense	181	405
Total interest expense related to the Notes	$ 6,706	$ 14,819
Effective interest rate of the liability component	5.60%	5.60%
[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

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	Oct. 31, 2018	Mar. 31, 2018	Jan. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Base rent obligation	$ 149,900,000		$ 113,000,000
Lessee, Lease, Description [Line Items]
Outstanding letters of credit	$ 10,800,000		$ 9,600,000
Letter of Credit
Lessee, Lease, Description [Line Items]
Principal amount		$ 1,500,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Millions	1 Months Ended
	Apr. 30, 2018USD ($)shares	Oct. 31, 2018class$ / sharesshares	Apr. 04, 2018$ / shares	Jan. 31, 2018$ / sharesshares	[1]
Equity [Abstract]
Preferred stock, shares authorized (in shares)		20,000,000		20,000,000
Preferred stock, shares issued (in shares)		0		0
Preferred stock, shares outstanding (in shares)		0		0
Number of classes of stock | class		2
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)		2,250,000,000		2,250,000,000
Common stock, par value per share (in dollars per share) | $ / shares		$ 0.0001		$ 0.0001
Common stock, shares issued (in shares)		241,359,000		220,979,000
Common stock, shares outstanding (in shares)		241,359,000		220,979,000
Closing price of stock (in dollars per share) | $ / shares		$ 20.18
Class A
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)		2,000,000,000		2,000,000,000
Common stock, par value per share (in dollars per share) | $ / shares		$ 0.0001		$ 0.0001
Common stock, shares issued (in shares)		216,252,136		129,502,000
Common stock, shares outstanding (in shares)		216,252,136		129,502,000
Stock repurchased and retired during period (in shares)	1,008,573
Stock repurchased and retired during period, value | $	$ 20
Closing price of stock (in dollars per share) | $ / shares		$ 20.18	$ 19.83
Class B
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)		250,000,000		250,000,000
Common stock, par value per share (in dollars per share) | $ / shares		$ 0.0001		$ 0.0001
Common stock, shares issued (in shares)		25,107,173		91,477,000
Common stock, shares outstanding (in shares)		25,107,173		91,477,000
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Equity Incentive Plans - Additi

Equity Incentive Plans - Additional Information (Details)	Mar. 16, 2016	Aug. 31, 2015USD ($)periodshares	Oct. 31, 2018USD ($)	Oct. 31, 2017USD ($)	Apr. 30, 2017USD ($)	Oct. 31, 2018USD ($)plan	Oct. 31, 2017USD ($)
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of equity incentive plans | plan						2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense			$ 58,329,000	$ 38,863,000		$ 155,938,000	$ 107,920,000
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity awards of vest expire period (no later than)						10 years
2015 Equity Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price as percentage of fair market value of common stock						100.00%
Equity awards of vest period						2 years
2015 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity awards of vest period						4 years
2015 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan offering period	24 months
Number of purchase periods | period		4
Purchase period, term		6 months
Total stock-based compensation expense			11,600,000	$ 4,700,000		$ 26,200,000	$ 12,600,000
Unrecognized stock-based compensation expense			$ 36,300,000			$ 36,300,000
Compensation cost, weighted average term						10 months 24 days
2015 Employee Stock Purchase Plan | Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price as percentage of fair market value of common stock		85.00%
Payroll deductions percentage		30.00%
Share cap for ESPP at purchase date (in shares) | shares		3,000
Calendar year gap for ESPP contribution amount		$ 25,000
Modification charges					$ 9,000,000

Equity Incentive Plans - Stock

Equity Incentive Plans - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Oct. 31, 2018	Jan. 31, 2018	Apr. 04, 2018
Options Outstanding, Number of Shares
Beginning balance (in shares)	46,359,949
Options exercised (in shares)	(8,249,893)
Options forfeited/cancelled (in shares)	(1,360,202)
Ending balance (in shares)	36,749,854	46,359,949
Options Outstanding, Number of Shares, Vested and exercisable (in shares)	26,221,996
Options Outstanding, Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 7.75
Options exercised (in dollars per share)	5.26
Options forfeited/cancelled (in dollars per share)	10.04
Ending balance (in dollars per share)	8.22	$ 7.75
Weighted Average Exercise Price, Vested and exercisable (in dollars per share)	$ 6.38
Weighted- Average Remaining Contractual Life
Weighted Average Remaining Contractual Life	5 years 7 months 6 days	6 years 3 months 18 days
Weighted Average Remaining Contractual Life, Vested and exercisable	5 years 2 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 439,185	$ 574,224
Aggregate Intrinsic Value, Vested and exercisable	$ 361,783
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of stock (in dollars per share)	$ 20.18
Unrecognized compensation cost, stock options	$ 40,200
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost, weighted average term	1 year 10 months 24 days
Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of stock (in dollars per share)	$ 20.18		$ 19.83

Equity Incentive Plans - Restri

Equity Incentive Plans - Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended
	Mar. 31, 2018	Aug. 31, 2017	Mar. 30, 2017	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Jan. 31, 2018
Weighted-Average Grant Date Fair Value
Stock-based compensation expense				$ 58,329	$ 38,863	$ 155,938	$ 107,920
Restricted Stock Units
Number of Restricted Stock Units Outstanding
Unvested, Beginning balance (in shares)						17,682,646
Granted (in shares)						11,098,371
Vested (in shares)						(6,429,146)
Forfeited (in shares)						(1,719,729)
Converted (in shares)	(1,375,210)					(1,142,838)
Unvested, Ending balance (in shares)				19,489,304		19,489,304
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)						$ 12.60
Granted (in dollars per share)						22.49
Vested (in dollars per share)						12.84
Forfeited (in dollars per share)						15.57
Converted (in dollars per share)						11.86
Ending balance (in dollars per share)				$ 17.92		$ 17.92
Aggregate Intrinsic Value				$ 393,270		$ 393,270		$ 356,117
Compensation not yet recognized				316,100		$ 316,100
Compensation cost, weighted average term						3 years
Performance Shares | Granted March 2017
Number of Restricted Stock Units Outstanding
Granted (in shares)			750,000
Forfeited (in shares)			(77,000)
Weighted-Average Grant Date Fair Value
Earned (in shares)	780,000
Stock-based compensation expense				$ 400	$ 1,300	$ 1,900	$ 2,900
Performance Shares | Granted March 2017 | Minimum
Weighted-Average Grant Date Fair Value
Award vesting rights, percentage			0.00%
Performance Shares | Granted March 2017 | Maximum
Weighted-Average Grant Date Fair Value
Award vesting rights, percentage			150.00%
Performance Shares | Granted August 2017
Number of Restricted Stock Units Outstanding
Granted (in shares)		464,744
Weighted-Average Grant Date Fair Value
Award vesting rights, percentage		100.00%
Performance Shares | Granted August 2017 | Minimum
Weighted-Average Grant Date Fair Value
Award vesting rights, percentage		0.00%
Performance Shares | Granted August 2017 | Maximum
Weighted-Average Grant Date Fair Value
Award vesting rights, percentage		150.00%

Equity Incentive Plans - Rest_2

Equity Incentive Plans - Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Jan. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 58,329	$ 38,863	$ 155,938	$ 107,920
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Converted (in shares)	1,375,210			1,142,838
Issued (in shares)				11,098,371
Compensation cost, weighted average term				3 years
Number of Restricted Stock Outstanding
Unvested, Beginning balance (in shares)				17,682,646
Vested (in shares)				(6,429,146)
Unvested, Ending balance (in shares)		19,489,304		19,489,304
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 12.60
Vested (in dollars per share)				12.84
Ending balance (in dollars per share)		$ 17.92		$ 17.92
Aggregate Intrinsic Value		$ 393,270		$ 393,270		$ 356,117
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		7,500		17,700
Unrecognized stock-based compensation expense		$ 26,300		$ 26,300
Compensation cost, weighted average term				2 years 4 months 17 days
Number of Restricted Stock Outstanding
Unvested, Beginning balance (in shares)				0
Granted and converted (in shares)				3,330,118
Vested (in shares)				(116,186)
Unvested, Ending balance (in shares)		3,213,932		3,213,932
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 0
Granted and converted (in dollars per share)				19.25
Vested (in dollars per share)				12.84
Ending balance (in dollars per share)		$ 19.49		$ 19.49
Aggregate Intrinsic Value		$ 64,857		$ 64,857		$ 0
Restricted Stock | Performance Vesting Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Converted (in shares)	697,116
Restricted Stock | Service Vesting Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Converted (in shares)	678,094
Restricted Stock | Performance Vesting at Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issued (in shares)				1,954,908
Restricted Stock | Maximum | Performance Vesting at Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage				180.00%
Restricted Stock | Minimum | Performance Vesting at Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage				0.00%

Equity Incentive Plans - Stock-

Equity Incentive Plans - Stock-Based Compensation Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 58,329	$ 38,863	$ 155,938	$ 107,920
Cost of revenue—product
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	862	143	2,190	898
Cost of revenue—support subscription
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	3,327	2,422	8,940	6,441
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	24,634	18,073	67,956	51,632
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	18,681	12,104	49,890	34,169
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 10,825	$ 6,121	$ 26,962	$ 14,780

Net Loss per Share Attributab_3

Net Loss per Share Attributable to Common Stockholders - Summary of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	[1]	Oct. 31, 2018	Oct. 31, 2017	[1]
Earnings Per Share [Abstract]
Net loss	$ (28,180)	$ (29,404)	[2]	$ (152,607)	$ (144,974)	[2],[3]
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	235,205	213,274		229,505	209,456
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.12)	$ (0.14)		$ (0.66)	$ (0.69)
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, 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 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

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Summary of Weighted-average Outstanding Shares Excluded from Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	60,820	69,667	63,707	69,571
Stock options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	37,814	51,685	41,201	53,786
Restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	19,493	17,201	19,488	14,913
Restricted stock and early exercised stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	3,277	196	2,938	287
Employee stock purchase plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	236	585	80	585

Income Taxes (Details)

Income Taxes (Details) $ in Millions	3 Months Ended
	Oct. 31, 2018USD ($)
StorReduce, Inc.
Business Acquisition [Line Items]
Release of deferred tax liability valuation allowance	$ 3.7

Segment Information - Additiona

Segment Information - Additional Information (Details)	9 Months Ended
	Oct. 31, 2018segment
Segment Reporting [Abstract]
Number of business activities	1
Number of reportable segments	1

Segment Information - Schedule

Segment Information - Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017		Oct. 31, 2018	Oct. 31, 2017
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 372,779	$ 277,591	[1]	$ 937,608	$ 684,906	[1]
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	263,488	192,919		678,166	505,045
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 109,291	$ 84,672		$ 259,442	$ 179,861
[1]	* Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.

Segment Information - Schedul_2

Segment Information - Schedule of Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Revenues From External Customers And Long Lived Assets [Line Items]
Total long-lived assets	$ 115,266	$ 89,142	[1]
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total long-lived assets	110,850	85,430
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total long-lived assets	$ 4,416	$ 3,712
[1]	*Prior period information has been adjusted to reflect the adoption impact of Accounting Standards Codification 606, Revenue from Contracts with Customers (ASC 606), which we adopted on February 1, 2018.

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event - USD ($)	Dec. 04, 2018	Nov. 30, 2018
Subsequent Event [Line Items]
Common stock, terms of conversion, conversion threshold as a percentage of aggregate number of shares outstanding	10.00%
HTSV Note | Senior Notes
Subsequent Event [Line Items]
Principal amount		$ 5,000,000
Interest rate		1.50%