Cover - shares	6 Months Ended
Cover - shares	Jul. 31, 2019	Aug. 26, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jul. 31, 2019
Document Transition Report	false
Entity File Number	001-37570
City Area Code	800
Local Phone Number	379-7873
Entity Registrant Name	Pure Storage, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-1069557
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Class A Common Stock, $0.0001 par value per share
Trading Symbol	PSTG
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding (in shares)		256,179,043
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001474432
Current Fiscal Year End Date	--01-31
Entity Address, Address Line One	650 Castro Street, Suite 400
Entity Address, City or Town	Mountain View
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94041

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Current assets:
Cash and cash equivalents	$ 268,938	$ 447,990
Marketable Securities	913,521	749,482
Accounts receivable, net of allowance of $660 and $614 as of January 31, 2019 and July 31, 2019	352,617	378,729
Inventory	35,820	44,687
Deferred commissions, current	31,273	29,244
Prepaid expenses and other current assets	47,776	51,695
Total current assets	1,649,945	1,701,827
Property and equipment, net	131,048	125,353
Operating lease right-of-use assets	114,339	0
Deferred commissions, non-current	87,295	85,729
Intangible assets, net	63,659	20,118
Goodwill	36,420	10,997
Deferred income taxes, non-current	939	1,060
Restricted cash	15,425	15,823
Other assets, non-current	16,904	12,118
Total assets	2,115,974	1,973,025
Current liabilities:
Accounts payable	64,582	103,462
Accrued compensation and benefits	70,753	99,910
Accrued expenses and other liabilities	44,690	39,860
Operating lease liabilities, current	26,005	0
Deferred revenue, current	308,523	266,584
Total current liabilities	514,553	509,816
Convertible senior notes, net	463,118	449,828
Operating lease liabilities, non-current	94,941	0
Deferred revenue, non-current	298,740	269,336
Deferred tax liabilities, non-current	5,697	0
Other liabilities, non-current	1,386	6,265
Total liabilities	1,378,435	1,235,245
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, par value of $0.0001 per share— 20,000 shares authorized as of January 31, 2019 and July 31, 2019; no shares issued and outstanding as of January 31, 2019 and July 31, 2019	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, 2019 and July 31, 2019; 243,524 and 255,752 Class A shares issued and outstanding as of January 31, 2019 and July 31, 2019	26	24
Additional paid-in capital	1,982,407	1,820,043
Accumulated other comprehensive income (loss)	3,409	(338)
Accumulated deficit	(1,248,303)	(1,081,949)
Total stockholders’ equity	737,539	737,780
Total liabilities and stockholders’ equity	$ 2,115,974	$ 1,973,025

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Accounts receivable, allowance	$ 614	$ 660
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Shares authorized (in shares)	20,000,000	20,000,000
Shares issued (in shares)	0	0
Shares outstanding (in shares)	0	0
Par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Shares authorized (in shares)	2,250,000,000	2,250,000,000
Shares issued (in shares)	241,359,000	220,979,000
Shares outstanding (in shares)	241,359,000	220,979,000
Class A
Par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Shares authorized (in shares)	2,000,000,000	2,000,000,000
Shares issued (in shares)	255,751,711	243,524,000
Shares outstanding (in shares)	255,752,000	243,524,000
Class B
Par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Shares authorized (in shares)	250,000,000	250,000,000
Shares issued (in shares)	0	0
Shares outstanding (in shares)	0	0

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Revenue	$ 396,327	$ 308,884	$ 723,027	$ 564,829
Cost of revenue	128,008	102,719	238,321	192,349
Gross profit	268,319	206,165	484,706	372,480
Operating expenses:
Research and development	107,020	84,031	212,095	162,523
Sales and marketing	186,188	143,749	352,814	266,116
General and administrative	40,016	33,591	82,126	60,921
Total operating expenses	333,224	261,371	647,035	489,560
Loss from operations	(64,905)	(55,206)	(162,329)	(117,080)
Other income (expense), net	(652)	(4,032)	(2,468)	(5,031)
Loss before provision for income taxes	(65,557)	(59,238)	(164,797)	(122,111)
Income tax provision	461	885	1,557	2,316
Net loss	$ (66,018)	$ (60,123)	$ (166,354)	$ (124,427)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.26)	$ (0.26)	$ (0.67)	$ (0.55)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	251,298	229,359	248,366	226,609
Product
Revenue	$ 300,128	$ 241,137	$ 538,869	$ 436,586
Cost of revenue	92,870	78,262	169,462	144,682
Support subscription
Revenue	96,199	67,747	184,158	128,243
Cost of revenue	$ 35,138	$ 24,457	$ 68,859	$ 47,667

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (66,018)	$ (60,123)	$ (166,354)	$ (124,427)
Other comprehensive income (loss) net of tax:
Change in unrealized net gain (loss) on available-for-sale securities	2,120	(193)	3,747	(909)
Comprehensive loss	$ (63,898)	$ (60,316)	$ (162,607)	$ (125,336)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Condensed Consolidated Statements of Stockholders’ Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Restricted Stock Units Common Stock	Restricted Stock Common Stock
Beginning balance (in shares) at Jan. 31, 2018		220,979
Beginning balance at Jan. 31, 2018	$ 574,401	$ 22	$ 1,479,883	$ (1,917)	$ (903,587)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		5,884
Issuance of common stock upon exercise of stock options	29,066	$ 1	29,065
Stock-based compensation expense	97,609		97,609
Vesting of restricted stock units (in shares)						4,117
Vesting of restricted stock units	0	$ 0	0
Vesting of early exercised stock options	320		320
Common stock issued under employee stock purchase plan (in shares)		2,111
Common stock issued under employee stock purchase plan	19,698		19,698
Issuance of restricted stock awards (in shares)							3,330
Issuance of restricted stock	1						$ 1
Repurchase of common stock (in shares)		(1,009)
Repurchase of common stock	(20,000)		(20,000)
Purchase of capped calls	(64,630)		(64,630)
Equity component of convertible senior notes, net	133,265		133,265
Other comprehensive loss	(909)			(909)
Net loss	(124,427)				(124,427)
Ending balance (in shares) at Jul. 31, 2018		235,412
Ending balance at Jul. 31, 2018	644,394	$ 24	1,675,210	(2,826)	(1,028,014)
Beginning balance (in shares) at Apr. 30, 2018		229,596
Beginning balance at Apr. 30, 2018	631,620	$ 23	1,602,121	(2,633)	(967,891)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		3,691
Issuance of common stock upon exercise of stock options	19,436	$ 1	19,435
Stock-based compensation expense	53,654		53,654
Vesting of restricted stock units (in shares)						2,104
Vesting of restricted stock units	0	$ 0	0
Issuance of restricted stock awards (in shares)							21
Issuance of restricted stock	0						$ 0
Other comprehensive loss	(193)			(193)
Net loss	(60,123)				(60,123)
Ending balance (in shares) at Jul. 31, 2018		235,412
Ending balance at Jul. 31, 2018	644,394	$ 24	1,675,210	(2,826)	(1,028,014)
Beginning balance (in shares) at Jan. 31, 2019		243,524
Beginning balance at Jan. 31, 2019	737,780	$ 24	1,820,043	(338)	(1,081,949)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		3,863
Issuance of common stock upon exercise of stock options	19,291	$ 1	19,290
Stock-based compensation expense	118,206		118,206
Vesting of restricted stock units (in shares)						4,327
Vesting of restricted stock units	0	$ 1	(1)
Tax withholding on vesting of restricted stock	(7,173)		(7,173)
Common stock issued under employee stock purchase plan (in shares)		2,973
Common stock issued under employee stock purchase plan	32,042		32,042
Issuance of restricted stock awards (in shares)							1,065
Other comprehensive loss	3,747			3,747
Net loss	(166,354)				(166,354)
Ending balance (in shares) at Jul. 31, 2019		255,752
Ending balance at Jul. 31, 2019	737,539	$ 26	1,982,407	3,409	(1,248,303)
Beginning balance (in shares) at Apr. 30, 2019		252,853
Beginning balance at Apr. 30, 2019	743,976	$ 25	1,924,947	1,289	(1,182,285)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		655
Issuance of common stock upon exercise of stock options	2,502	$ 0	2,502
Stock-based compensation expense	56,460		56,460
Vesting of restricted stock units (in shares)						2,277
Vesting of restricted stock units	0	$ 1	(1)
Tax withholding on vesting of restricted stock	(1,501)		(1,501)
Issuance of restricted stock awards (in shares)							(33)
Issuance of restricted stock	0
Other comprehensive loss	2,120			2,120
Net loss	(66,018)				(66,018)
Ending balance (in shares) at Jul. 31, 2019		255,752
Ending balance at Jul. 31, 2019	$ 737,539	$ 26	$ 1,982,407	$ 3,409	$ (1,248,303)

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (166,354)	$ (124,427)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	43,591	33,590
Amortization of debt discount and debt issuance costs	13,290	7,889
Stock-based compensation expense	120,561	97,609
Other	327	82
Changes in operating assets and liabilities, net of effects of acquisition:
Accounts receivable, net	26,553	707
Inventory	6,852	(8,900)
Deferred commissions	(3,595)	(4,155)
Prepaid expenses and other assets	(635)	11,134
Operating lease right-of-use assets	13,438	0
Accounts payable	(30,827)	(18,135)
Accrued compensation and other liabilities	(25,704)	(7,458)
Operating lease liabilities	(13,083)	0
Deferred revenue	71,045	39,144
Net cash provided by operating activities	55,459	27,080
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(53,229)	(42,733)
Acquisition, net of cash acquired	(47,881)	0
Purchase of intangible assets	(9,000)	0
Purchases of marketable securities	(488,497)	(494,507)
Sales of marketable securities	60,368	13,585
Maturities of marketable securities	270,756	97,793
Net cash used in investing activities	(267,483)	(425,862)
CASH FLOWS FROM FINANCING ACTIVITIES
Net proceeds from exercise of stock options	19,260	29,067
Proceeds from issuance of common stock under employee stock purchase plan	32,042	19,698
Proceeds from issuance of convertible senior notes, net of issuance costs	0	562,062
Payment for purchase of capped calls	0	(64,630)
Repayment of debt assumed from acquisition	(11,555)	0
Tax withholding on vesting of restricted stock	(7,173)	0
Repurchase of common stock	0	(20,000)
Net cash provided by financing activities	32,574	526,197
Net increase (decrease) in cash, cash equivalents and restricted cash	(179,450)	127,415
Cash, cash equivalents and restricted cash, beginning of period	463,813	258,820
Cash, cash equivalents and restricted cash, end of period	284,363	386,235
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD:
Cash, cash equivalents and restricted cash, end of period	463,813	258,820
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for income taxes	2,716	3,023
Cash paid for interest	359	0
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION
Property and equipment purchased but not yet paid	5,717	11,949
Vesting of early exercised stock options	$ 0	$ 320

Business Overview	6 Months Ended
Business Overview	Jul. 31, 2019
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 innovative data platform replaces storage systems designed for mechanical disk with all-flash systems optimized for end-to-end for solid-state memory. Our cloud-based management and support platform helps predictively resolve potential issues and simplify storage administration. We provide a customer first business model that replaces the traditional forklift upgrade cycle with a subscription model built to keep customers on the cutting edge without downtime or performance impact.

Basis of Presentation and Summary of Significant Accounting Policies

6 Months Ended

Jul. 31, 2019

Accounting Policies [Abstract]

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, 2019.

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 2020 or any future period.

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, the period of benefit for deferred contract costs for commissions, stock-based compensation, provision for income taxes including related reserves, valuation of intangible assets and goodwill, the incremental borrowing rate we use to determine our operating lease liabilities, 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 for letters of credit related to our leases and for a vendor credit card program. As of January 31, 2019 and July 31, 2019, we had restricted cash of $15.8 million and $15.4 million.

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 income (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 Combinations

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. During the measurement period, which may be up to one year from the acquisition date, we may record adjustments to the estimated fair value of the assets acquired and liabilities assumed, with the corresponding offset to goodwill. The results of operations of an acquired business is 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 revenue 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 July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Beginning balance ⁽¹⁾	$	86,044		$	113,257		$	87,313		$	114,973
Additions	24,582			30,074			40,003			48,310
Recognition of deferred commissions	(19,157		)	(24,763		)	(35,847		)	(44,715		)
Ending balance	$	91,469		$	118,568		$	91,469		$	118,568

____________________________________

⁽¹⁾ Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606.

Of the $118.6 million total deferred commissions balance as of July 31, 2019, we expect to recognize approximately 26% as commission expense over the next 12 months and the remainder thereafter.

There was no impairment related to capitalized commissions for the three and six months ended July 31, 2018 and 2019.

Operating Leases

We determine if an arrangement contains a lease at inception. Lease liabilities are recognized at the present value of the future lease payments at commencement date. The interest rate implicit in our operating leases is not readily determinable, and therefore an incremental borrowing rate is estimated to determine the present value of future payments. The estimated incremental borrowing rate factors in a hypothetical interest rate on a collateralized basis with similar terms, payments, and economic environments. The operating lease right-of-use (ROU) asset is determined based on the lease liability initially established and reduced for any prepaid lease payments and any lease incentives. We combine lease and non-lease components for our leases.

Certain of the operating lease agreements contain rent concession, rent escalation, and option to renew provisions. Rent concession and rent escalation provisions are considered in determining the straight-line lease cost to be recorded over the lease term. Lease cost is recognized on a straight-line basis over the lease term commencing on the date we have the right to use the leased property. We generally use the base, non-cancelable, lease term when recognizing the lease assets and liabilities, unless it is reasonably certain that an extension or termination option will be exercised.

In addition, certain of our operating lease agreements contain tenant improvement allowances from our landlords. These allowances are accounted for as lease incentives and decrease our ROU asset and reduce single lease cost over the lease term.

For short-term leases which have a lease term of less than twelve months and do not include an option to purchase the underlying asset that we are reasonably certain to exercise, we recognize rent expense in our condensed consolidated statements of operations on a straight-line basis over the lease term and record variable lease payments as incurred.

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 July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Beginning balance ⁽¹⁾	$	388,614		$	564,230		$	374,102		$	535,920
Additions	92,511			140,548			167,782			258,441
Recognition of deferred revenue	(67,878		)	(97,515		)	(128,637		)	(187,098		)
Ending balance	$	413,247		$	607,263		$	413,247		$	607,263

____________________________________

⁽¹⁾ Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606.

During the three and six months ended July 31, 2018, we recognized $60.9 million and $106.2 million in revenue pertaining to deferred revenue as of the beginning of each period. During the three and six months ended July 31, 2019, we recognized $88.2 million and $150.2 million in revenue pertaining to deferred revenue as of the beginning of each period.

Total contracted but not recognized revenue was $770.1 million as of July 31, 2019. Contracted but not recognized revenue consists of both deferred revenue and non-cancelable amounts that will be invoiced and recognized as revenue in future periods. Of the $770.1 million contracted but not recognized revenue as of July 31, 2019, we expect to recognize approximately 41% over the next 12 months, and the remainder thereafter.

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. Support subscription revenue also includes our Evergreen Storage Service (ES2) offering.

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. Support subscription revenue is also derived from the sale of our ES2 offering. Revenue related to support revenue 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 separate performance obligation. The transaction price is determined based on the consideration which we will be entitled to in exchange for transferring goods or services to the customer. We allocate transaction price to each performance obligation for contracts that contain multiple performance obligations based on a relative standalone selling price which is determined based on the price at which the performance obligation is sold separately, or if not observable through past transactions, is estimated taking into account available information such as market conditions and internally approved pricing guidelines related to performance obligations.

Recently Adopted Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2016-02, Leases (ASC 842) and subsequent amendments to the initial guidance (collectively, Topic 842). ASC 842 requires lessees to generally recognize on its balance sheet operating and financing lease liabilities and corresponding ROU assets at the commencement date, and to recognize the associated lease expenses in the condensed consolidated statement of operations in a manner similar to that required under historical accounting rules.

On February 1, 2019, we adopted ASC 842 using the modified retrospective approach by electing to use the optional transition method which allows us to continue to apply the guidance of ASC 840, including disclosure requirements, in the comparative periods presented. We elected the package of transition expedients, which allowed us to carry forward our historical lease classifications, our assessment of whether any existing leases as of the date of adoption are or contain leases, and our assessment of indirect costs for any leases that existed prior to adoption of the new standard. We elected to take the practical expedient to keep leases with an initial term of 12 months or less off the condensed consolidated balance sheet and recognize the associated lease payments in the consolidated statements of operations on a straight-line basis over the lease term. We recognized operating ROU assets of $124.5 million and lease liabilities of $130.6 million on our condensed consolidated balance sheet as of February 1, 2019, which included reclassifying prepaid rent and deferred rent as a component of the ROU asset. Topic 842 did not have a material impact on our condensed consolidated statements of operations and cash flows. Refer to Note 8 for additional disclosures.

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 and requires certain disclosures about stranded tax effects. We adopted this standard on February 1, 2019 and the adoption had no impact on our condensed consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

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 condensed 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 condensed 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 will be applied either retrospectively or prospectively. Early adoption is permitted. We are currently evaluating the impact of this standard on our condensed consolidated financial statements.

Financial Instruments

6 Months Ended

Jul. 31, 2019

Investments, Debt and Equity Securities [Abstract]

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 July 31, 2019 to be a Level 2 measurement due to its limited trading activity. Refer to Note 6 for the carrying amount and estimated fair value of our Notes as of July 31, 2019.

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, 2019 and July 31, 2019 (in thousands):



	As of January 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash Equivalents		Marketable Securities		Restricted Cash
Level 1
Money market accounts	$	—	$	—	$	—		$	43,038	$	27,215	$	—	$	15,823
Level 2
U.S. government treasury notes	315,329		208		(315		)	315,222		34,129		281,093		—
U.S. government agencies	69,114		17		(154		)	68,977		9,983		58,994		—
Corporate debt securities	363,860		534		(757		)	363,637		—		363,637		—
Foreign government bonds	7,965		36		—			8,001		—		8,001		—
Asset-backed securities	37,664		105		(12		)	37,757		—		37,757		—
Total	$	793,932	$	900	$	(1,238	)	$	836,632	$	71,327	$	749,482	$	15,823



	As of July 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash Equivalents		Marketable Securities		Restricted Cash
Level 1
Money market accounts	$	—	$	—	$	—		$	36,659	$	21,234	$	—	$	15,425
Level 2
U.S. government treasury notes	348,463		1,454		(58		)	349,859		—		349,859		—
U.S. government agencies	66,153		222		(22		)	66,353		—		66,353		—
Corporate debt securities	427,362		2,685		(111		)	429,936		1,029		428,907		—
Foreign government bonds	8,480		100		—			8,580		—		8,580		—
Asset-backed securities	59,504		329		(11		)	59,822		—		59,822		—
Total	$	909,962	$	4,790	$	(202	)	$	951,209	$	22,263	$	913,521	$	15,425

The amortized cost and estimated fair value of our marketable securities are shown below by contractual maturity (in thousands):



	As of July 31, 2019
	Amortized Cost		Fair Value
Due within one year	$	336,156	$	336,736
Due in one to five years	572,777		576,785
Total	$	908,933	$	913,521

Based on our evaluation of available evidence, we concluded that the gross unrealized losses on our investments as of July 31, 2019 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 July 31, 2019, aggregated by investment category (in thousands):



	Less than 12 months					Greater than 12 months					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
U.S. government treasury notes	$	27,887	$	(30	)	$	9,737	$	(28	)	$	37,624	$	(58	)
U.S. government agencies	5,215		(7		)	9,183		(15		)	14,398		(22		)
Corporate debt securities	38,856		(28		)	43,245		(83		)	82,101		(111		)
Asset-backed securities	9,399		(11		)	—		—			9,399		(11		)
Total	$	81,357	$	(76	)	$	62,165	$	(126	)	$	143,522	$	(202	)

Realized gains or losses on sale of marketable securities were not significant for all periods presented.

Business Combination	6 Months Ended
Business Combination	Jul. 31, 2019
Business Combinations [Abstract]
Business Combination	Business Combination In April 2019, we acquired Compuverde AB (Compuverde), a privately-held developer of file software solutions for enterprises and cloud providers based in Sweden. Acquisition-related costs were $0.5 million and expensed as incurred. The purchase consideration was $47.9 million in cash (net of cash acquired) after repayment of $11.6 million of debt assumed. The purchase price was allocated as follows: $38.4 million in developed technology which will be amortized over seven years, $25.4 million of goodwill, $10.2 million in net liabilities assumed, and $5.7 million in deferred tax liability. 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 Compuverde's technology with our data platform to expand our file capabilities and is not expected to be deductible for tax purposes. In addition, we will make payments to founders of Compuverde totaling $15.9 million in cash payable over a two-year period, subject to continuous employment. As a result, these contingent payments are considered post-acquisition consideration to be recognized over the two-year period as compensation. Restricted stock units in the amount of $3.0 million were issued to Compuverde employees in June 2019, subject to continuous employment and will be recognized as stock-based compensation over the related vesting period. The results of Compuverde are included in our condensed consolidated statements of operations since the acquisition date, including revenue 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

6 Months Ended

Jul. 31, 2019

Balance Sheet Components Disclosure [Abstract]

Balance Sheet Components

Inventory

Inventory consists of the following (in thousands):



	As of January 31, 2019		As of July 31, 2019
Raw materials	$	3,349	$	2,623
Finished goods	41,338		33,197
Inventory	$	44,687	$	35,820

Property and Equipment, Net

Property and equipment, net consists of the following (in thousands):



	As of January 31, 2019			As of July 31, 2019
Test equipment	$	170,930		$	191,846
Computer equipment and software	117,330			135,178
Furniture and fixtures	6,980			7,732
Leasehold improvements	34,286			37,866
Total property and equipment	329,526			372,622
Less: accumulated depreciation and amortization	(204,173		)	(241,574		)
Property and equipment, net	$	125,353		$	131,048

Depreciation and amortization expense was $16.8 million and $19.9 million for the three months ended July 31, 2018 and 2019, and $32.8 million and $39.7 million for the six months ended July 31, 2018 and 2019.

Intangible Assets, Net

Intangible assets, net consist of the following (in thousands):



	As of January 31, 2019							As of July 31, 2019
	Gross Carrying Value		Accumulated Amortization			Net Carrying Amount		Gross Carrying Value		Accumulated Amortization			Net Carrying Amount
Technology patents	$	10,125	$	(6,572	)	$	3,553	$	19,125	$	(7,538	)	$	11,587
Developed technology	17,700		(1,135		)	16,565		56,100		(4,028		)	52,072
Intangible assets, net	$	27,825	$	(7,707	)	$	20,118	$	75,225	$	(11,566	)	$	63,659

Intangible assets amortization expense was $0.4 million and $2.6 million for the three months ended July 31, 2018 and 2019, and $0.8 million and $3.9 million for the six months ended July 31, 2018 and 2019. As of July 31, 2019, the weighted-average remaining amortization period was 4.2 years for technology patents and 6.5 years for developed technology. Amortization of the technology patents is included in general and administrative expenses due to their defensive nature and amortization of developed technology is included in cost of product revenue in the condensed consolidated statements of operations. During the three months ended July 31, 2019, we acquired a portfolio of technology patents for $9.0 million with a useful life of 7.0 years.

As of July 31, 2019, future expected amortization expense for intangible assets is as follows (in thousands):



Fiscal Years Ending January 31,	Estimated Future Amortization Expense
Remainder of 2020	$	5,402
2021	10,804
2022	9,846
2023	9,300
2024	9,300
Thereafter	19,007
Total	$	63,659

Goodwill

The change in the carrying amount of goodwill is as follows (in thousands):



	Amount
Balance as of January 31, 2019	$	10,997
Goodwill acquired	25,423
Balance as of July 31, 2019	$	36,420

Accrued Expenses and Other Liabilities

Accrued expenses and other liabilities consist of the following (in thousands):



	As of January 31, 2019		As of July 31, 2019
Taxes payable	$	7,146	$	4,967
Accrued marketing	6,173		11,005
Accrued travel and entertainment expenses	3,570		3,055
Acquisition consideration held back	3,725		3,725
Other accrued liabilities	19,246		21,938
Total accrued expenses and other liabilities	$	39,860	$	44,690

Convertible Senior Notes

6 Months Ended

Jul. 31, 2019

Debt Disclosure [Abstract]

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 $9.8 million was allocated to the Notes and $3.1 million was allocated to additional paid-in capital.

The Notes consisted of the following (in thousands):



	As of July 31, 2019
Liability:
Principal	$	575,000
Less: debt discount, net of amortization	(104,329		)
Less: debt issuance costs, net of amortization	(7,553		)
Net carrying amount of the Notes	$	463,118

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 July 31, 2019 was $558.7 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 $15.14 on July 31, 2019, the if-converted value of the Notes of $331.3 million was less than its principal amount.

The following table sets forth total interest expense recognized related to the Notes for three and six months ended July 31, 2018 and 2019 (in thousands):



	Three Months Ended July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Amortization of debt discount	$	6,000		$	6,341		$	7,357		$	12,393
Amortization of debt issuance costs	434			459			532			897
Total amortization of debt discount and debt issuance costs	6,434			6,800			7,889			13,290
Contractual interest expense	181			181			224			358
Total interest expense related to the Notes	$	6,615		$	6,981		$	8,113		$	13,648

Effective interest rate of the liability component	5.6		%	5.6		%	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	6 Months Ended
Commitments and Contingencies	Jul. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases As of July 31, 2019, we have various non-cancelable operating lease commitments for office facilities which as a result of the adoption of ASC 842, have been recorded as operating lease liabilities on our condensed consolidated balance sheet. Refer to Note 8—Leases for additional information regarding lease commitments. Convertible Notes The repayment of our Notes with an aggregate principal amount of $575.0 million is due on April 15, 2023. Refer to Note 6 for further information regarding our Notes. Letters of Credit In connection with a lease executed in January 2019, we issued a letter of credit of $0.5 million. As of January 31, 2019 and July 31, 2019, we had outstanding letters of credit in the aggregate amount of $10.8 million and $11.6 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 July 31, 2019. 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.

Leases

6 Months Ended

Jul. 31, 2019

Leases [Abstract]

Leases

We lease office facilities under non-cancelable operating lease agreements expiring through October 2028. Our lease agreements do not contain any material residual value guarantees or restrictive covenants. The components of lease costs were as follows (in thousands):



	Three Months Ended		Six Months Ended
	July 31, 2019		July 31, 2019
Fixed operating lease cost	$	8,228	$	16,711
Variable lease cost ⁽¹⁾	2,242		4,342
Short-term lease cost (12 months or less)	1,484		2,345
Total lease cost	$	11,954	$	23,398

——————————

⁽¹⁾Variable lease cost for the three and six months ended July 31, 2019 predominantly includes common area maintenance charges.

Future lease payments under our non-cancelable operating leases as of July 31, 2019 were as follows (in thousands):



Fiscal Years Ending January 31,	Operating Leases
The remainder of 2020	$	16,579
2021	33,269
2022	26,781
2023	21,478
2024	15,434
Thereafter	31,236
Total future lease payments	144,777
Less: imputed interest	(23,831		)
Present value of lease liabilities	$	120,946

Supplemental cash flow information related to our operating leases for the six months ended July 31, 2019 as well as the weighted-average remaining lease term and weighted-average discount rate as of July 31, 2019 were as follows:



Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$	16,167
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$	3,449
Weighted-average remaining lease term (years)	5.28
Weighted-average discount rate	6.46		%

As previously disclosed in our Annual Report on Form 10-K for the year ended January 31, 2019 and under the previous lease accounting standard, ASC 840, Leases, the following table summarizes the future minimum lease payments due under operating leases as of January 31, 2019 (in thousands):



Year Ending January 31,	Operating Leases
2020	$	31,297
2021	28,573
2022	24,381
2023	20,440
2024	14,780
Thereafter	30,096
Total	$	149,567

Stockholders' Equity	6 Months Ended
Stockholders' Equity	Jul. 31, 2019
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 July 31, 2019, 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 July 31, 2019, we had 2,000,000,000 authorized shares of Class A common stock and 250,000,000 authorized shares of Class B common stock, with each class having a par value of $0.0001 per share. As of July 31, 2019, 255,751,711 shares of Class A common stock were issued and outstanding. Common Stock Repurchase Program In August 2019, our board of directors approved the repurchase of up to $150.0 million of our Class A common stock. The authorization allows us to repurchase shares of our Class A common stock opportunistically and will be funded from available working capital. Repurchases may be made at management’s discretion from time to time on the open market through privately negotiated transactions, transactions structured through investment banking institutions, block purchase techniques, 10b5-1 trading plans, or a combination of the foregoing. The repurchase program does not obligate us to acquire any of our common stock, has no end date, and may be suspended or discontinued by us at any time without prior notice. 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

6 Months Ended

Jul. 31, 2019

Share-based Payment Arrangement [Abstract]

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). The 2015 Plan became effective in connection with our initial public offering (IPO) in October 2015 and serves as the successor to our 2009 Plan. The 2015 Plan provides for grants of incentive stock options to our employees and non-statutory stock options, stock appreciation rights, restricted stock, restricted stock unit awards (RSUs), performance stock awards, performance cash awards, and other forms of stock awards to our employees, directors and consultants. No new awards have been issued under our 2009 Plan after the effective date of our 2015 Plan. Outstanding awards granted under our 2009 Plan will remain subject to the terms of our 2009 Plan and applicable award agreements, until such outstanding awards that are stock options are exercised, terminated or expired by their terms.

Starting in December 2018, we net-share settle equity awards held by certain employees by withholding shares upon vesting to satisfy tax withholding obligations. The shares withheld to satisfy employee tax withholding obligations are returned to our 2015 Plan and will be available for future issuance. Payments for employees’ tax obligations to the tax authorities are recognized as a reduction to additional paid-in capital and reflected as a financing activity in our condensed consolidated statements of cash flows.

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

Our 2015 Employee Stock Purchase Plan (2015 ESPP) 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). In February 2019, we amended the ESPP on a prospective basis, to include an additional dollar cap of $7,500 per purchase period. The 2015 ESPP provides for a 24-month offering period beginning March 16th and September 16th of each year, and each offering period consists of four 6 months 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 (1) on 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, 2019 that resulted in a total modification charge of $2.2 million, which is recognized over the new offering period ending March 15, 2021.

We recognized stock-based compensation expense related to our 2015 ESPP of $7.9 million and $4.2 million during the three months ended July 31, 2018 and 2019 and $14.6 million and $15.7 million during the six months ended July 31, 2018 and 2019. As of July 31, 2019, there was $19.4 million of unrecognized stock-based compensation expense related to our 2015 ESPP, which is expected to be recognized over a weighted-average period of 1.5 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, 2019	35,465,543		$	8.34	5.4	$	339,591
Options exercised	(3,862,965	)	4.99
Options forfeited/canceled	(343,662	)	15.49
Balance as of July 31, 2019	31,258,916		$	8.67	3.9	$	218,450
Vested and exercisable as of July 31, 2019	25,407,263		$	7.54	4.8	$	203,215

The aggregate intrinsic value of options vested and exercisable as of July 31, 2019 is calculated based on the difference between the exercise price and the closing price of $15.14 of our Class A common stock on July 31, 2019.

As of July 31, 2019, total unrecognized employee compensation cost related to outstanding options was $20.6 million, which is expected to be recognized over a weighted-average period of 1.6 years.

RSUs

A summary of the RSU activity under our 2015 Plan and related information is as follows:



	Number of RSUs Outstanding		Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Unvested balance as of January 31, 2019	21,917,550		$	17.94	$	392,515
Granted	8,792,982		19.81
Vested	(4,352,885	)	16.38
Forfeited	(1,324,694	)	18.47
Unvested balance as of July 31, 2019	25,032,953		$	18.84	$	378,999

During the three months ended July 31, 2018 and 2019, we recognized, $29.5 million and $40.4 million in stock-based compensation expense relating to RSUs. During the six months ended July 31, 2018 and 2019, we recognized $55.9 million and $77.7 million in stock-based compensation expense relating to RSUs. As of July 31, 2019, total unrecognized employee compensation cost related to unvested RSUs was $427.8 million, which is expected to be recognized over a weighted-average period of 3.0 years.

Restricted Stock

In January 2019, we issued 183,902 shares of performance restricted stock, at a target percentage of 100%, with both performance and service vesting conditions payable in common shares, from 0% to 160%, of the target number granted, contingent upon the degree to which the performance condition is met. The grant date for these shares was subsequently established when the performance condition was determined in March 2019. Any portion of shares that are not earned will be canceled.

During the three and six months ended July 31, 2019, we issued 60,716 and 1,291,194 shares of performance restricted stock, at a target percentage of 100%, with both performance and service vesting conditions payable in common shares, from 0% to 160%, of the target number granted, contingent upon the degree to which the performance condition is met. Any portion of shares that are not earned will be canceled. During the six months ended July 31, 2019, we also issued 108,494 shares of additional restricted stock earned based on the actual attainment of previously issued performance restricted stock awards.

A summary of the restricted stock activity under our 2015 Plan and related information is as follows:



	Number of Restricted Stock Outstanding		Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Unvested balance as of January 31, 2019	2,267,569		$	18.70	$	40,612
Granted	1,399,688		20.30
Vested	(843,321	)	19.85
Unvested balance as of July 31, 2019	2,823,936		$	19.25	$	42,754

All unvested restricted shares are subject to cancellation to the extent vesting conditions are not met. During the three months ended July 31, 2018 and 2019, we recognized $6.7 million and $7.4 million in stock-based compensation expense relating to restricted stock. During the six months ended July 31, 2018 and 2019, we recognized $10.2 million and $14.8 million in stock-based compensation expense relating to restricted stock. As of July 31, 2019,

total unrecognized employee compensation cost related to unvested restricted stock was $30.6 million, which is expected to be recognized over a weighted-average period of 2.3 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 July 31,				Six Months Ended July 31,
	2018		2019		2018		2019
Cost of revenue—product	$	720	$	954	$	1,328	$	1,931
Cost of revenue—support subscription	2,929		3,633		5,613		7,584
Research and development	22,232		29,108		43,322		57,353
Sales and marketing	17,269		16,055		31,209		34,369
General and administrative	10,504		8,654		16,137		19,324
Total stock-based compensation expense	$	53,654	$	58,404	$	97,609	$	120,561

The tax benefit related to stock-based compensation expense for all periods presented was not material.

Net Loss per Share Attributable to Common Stockholders

6 Months Ended

Jul. 31, 2019

Earnings Per Share [Abstract]

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 attributable to common stockholders 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 RSUs, repurchasable shares from early exercised stock options and restricted stock, our Notes to the extent dilutive, and common stock issuable pursuant to the ESPP. 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 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 July 31,						Six Months Ended July 31,
	2018			2019			2018			2019

Net loss	$	(60,123	)	$	(66,018	)	$	(124,427	)	$	(166,354	)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	229,359			251,298			226,609			248,366
Net loss per share attributable to common stockholders, basic and diluted	$	(0.26	)	$	(0.26	)	$	(0.55	)	$	(0.67	)

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 July 31,		Six Months Ended July 31,
	2018	2019	2018	2019
Stock options to purchase common stock	40,920	31,739	42,923	32,852
Unvested RSUs	19,957	25,513	19,486	24,743
Restricted stock and early exercised stock options subject to repurchase	3,327	2,917	2,585	2,777
Shares related to Notes	21,884	21,884	13,783	21,884
Shares issuable pursuant to ESPP	1,154	720	1,127	720
Total	87,242	82,773	79,904	82,976

Other Income (Expense), Net

6 Months Ended

Jul. 31, 2019

Other Income and Expenses [Abstract]

Other Income (Expense), Net

Other income (expense), net consists of the following (in thousands):



	Three Months Ended July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Interest income ⁽¹⁾	$	4,783		$	6,772		$	6,654		$	13,606
Interest expense ⁽²⁾	(6,615		)	(6,981		)	(8,113		)	(13,648		)
Foreign currency transactions losses	(2,273		)	(443		)	(4,407		)	(2,426		)
Other income	73			—			835			—
Total other income (expense), net	$	(4,032	)	$	(652	)	$	(5,031	)	$	(2,468	)

____________________________________

⁽¹⁾Interest income includes interest income related to our cash, cash equivalents and marketable securities and non-cash interest income related to accretion (amortization) of the discount (premium) on marketable securities.

⁽²⁾ Interest expense includes non-cash interest expense related to amortization of the debt discount and debt issuance costs and the contractual interest expense related to the Notes for the three and six months ended July 31, 2018 and 2019.

Income Taxes	6 Months Ended
Income Taxes	Jul. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our income tax provision was primarily due to taxes on international operations and state income taxes. The difference between the income tax provision that would be derived by applying the statutory rate to our loss before income taxes and the income tax provision 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. As of July 31, 2019, 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, 2019.

Segment Information

6 Months Ended

Jul. 31, 2019

Segment Reporting [Abstract]

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 July 31,				Six Months Ended July 31,
	2018		2019		2018		2019

United States	$	229,760	$	294,596	$	414,678	$	523,535
Rest of the world	79,124		101,731		150,151		199,492
Total revenue	$	308,884	$	396,327	$	564,829	$	723,027

Long-lived Assets by Geographic Area

Long-lived assets, which are comprised of property and equipment, net, by geographic area are summarized as follows (in thousands):



	As of January 31, 2019		As of July 31, 2019

United States	$	120,876	$	121,454
Rest of the world	4,477		9,594
Total long-lived assets	$	125,353	$	131,048

Subsequent Event	6 Months Ended
Subsequent Event	Jul. 31, 2019
Subsequent Events [Abstract]
Subsequent Event	Subsequent events Share Repurchase Program In August 2019, our board of directors approved a share repurchase program. All material terms of this program are disclosed in Note 9 Stockholders’ Equity. Departure of Officer In August 2019, we announced that Timothy Riitters, our Chief Financial Officer, will be departing later this year. Mr. Riitters' departure is not related to any issues regarding the integrity of our financial statements, accounting policies and practices.

Basis of Presentation and Summary of Significant Accounting Policies - (Policies)

6 Months Ended

Jul. 31, 2019

Accounting Policies [Abstract]

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, 2019.

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 2020 or any future period.

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, the period of benefit for deferred contract costs for commissions, stock-based compensation, provision for income taxes including related reserves, valuation of intangible assets and goodwill, the incremental borrowing rate we use to determine our operating lease liabilities, 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 for letters of credit related to our leases and for a vendor credit card program.

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 income (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 Combinations

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. During the measurement period, which may be up to one year from the acquisition date, we may record adjustments to the estimated fair value of the assets acquired and liabilities assumed, with the corresponding offset to goodwill. The results of operations of an acquired business is 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 revenue 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.

Operating Leases

We determine if an arrangement contains a lease at inception. Lease liabilities are recognized at the present value of the future lease payments at commencement date. The interest rate implicit in our operating leases is not readily determinable, and therefore an incremental borrowing rate is estimated to determine the present value of future payments. The estimated incremental borrowing rate factors in a hypothetical interest rate on a collateralized basis with similar terms, payments, and economic environments. The operating lease right-of-use (ROU) asset is determined based on the lease liability initially established and reduced for any prepaid lease payments and any lease incentives. We combine lease and non-lease components for our leases.

Certain of the operating lease agreements contain rent concession, rent escalation, and option to renew provisions. Rent concession and rent escalation provisions are considered in determining the straight-line lease cost to be recorded over the lease term. Lease cost is recognized on a straight-line basis over the lease term commencing on the date we have the right to use the leased property. We generally use the base, non-cancelable, lease term when recognizing the lease assets and liabilities, unless it is reasonably certain that an extension or termination option will be exercised.

In addition, certain of our operating lease agreements contain tenant improvement allowances from our landlords. These allowances are accounted for as lease incentives and decrease our ROU asset and reduce single lease cost over the lease term.

For short-term leases which have a lease term of less than twelve months and do not include an option to purchase the underlying asset that we are reasonably certain to exercise, we recognize rent expense in our condensed consolidated statements of operations on a straight-line basis over the lease term and record variable lease payments as incurred.

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. Support subscription revenue also includes our Evergreen Storage Service (ES2) offering.

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. Support subscription revenue is also derived from the sale of our ES2 offering. Revenue related to support revenue 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 separate performance obligation. The transaction price is determined based on the consideration which we will be entitled to in exchange for transferring goods or services to the customer. We allocate transaction price to each performance obligation for contracts that contain multiple performance obligations based on a relative standalone selling price which is determined based on the price at which the performance obligation is sold separately, or if not observable through past transactions, is estimated 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 February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2016-02, Leases (ASC 842) and subsequent amendments to the initial guidance (collectively, Topic 842). ASC 842 requires lessees to generally recognize on its balance sheet operating and financing lease liabilities and corresponding ROU assets at the commencement date, and to recognize the associated lease expenses in the condensed consolidated statement of operations in a manner similar to that required under historical accounting rules.

On February 1, 2019, we adopted ASC 842 using the modified retrospective approach by electing to use the optional transition method which allows us to continue to apply the guidance of ASC 840, including disclosure requirements, in the comparative periods presented. We elected the package of transition expedients, which allowed us to carry forward our historical lease classifications, our assessment of whether any existing leases as of the date of adoption are or contain leases, and our assessment of indirect costs for any leases that existed prior to adoption of the new standard. We elected to take the practical expedient to keep leases with an initial term of 12 months or less off the condensed consolidated balance sheet and recognize the associated lease payments in the consolidated statements of operations on a straight-line basis over the lease term. We recognized operating ROU assets of $124.5 million and lease liabilities of $130.6 million on our condensed consolidated balance sheet as of February 1, 2019, which included reclassifying prepaid rent and deferred rent as a component of the ROU asset. Topic 842 did not have a material impact on our condensed consolidated statements of operations and cash flows. Refer to Note 8 for additional disclosures.

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 and requires certain disclosures about stranded tax effects. We adopted this standard on February 1, 2019 and the adoption had no impact on our condensed consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

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 condensed 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 condensed 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 will be applied either retrospectively or prospectively. Early adoption is permitted. We are currently evaluating the impact of this standard on our condensed consolidated financial statements.

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 July 31, 2019 to be a Level 2 measurement due to its limited trading activity. Refer to Note 6 for the carrying amount and estimated fair value of our Notes as of July 31, 2019

Basis of Presentation and Summary of Significant Accounting Policies - (Tables)

6 Months Ended

Jul. 31, 2019

Accounting Policies [Abstract]

Deferred Commissions

Changes in total deferred commissions during the periods presented are as follows (in thousands):



	Three Months Ended July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Beginning balance ⁽¹⁾	$	86,044		$	113,257		$	87,313		$	114,973
Additions	24,582			30,074			40,003			48,310
Recognition of deferred commissions	(19,157		)	(24,763		)	(35,847		)	(44,715		)
Ending balance	$	91,469		$	118,568		$	91,469		$	118,568

____________________________________

⁽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 July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Beginning balance ⁽¹⁾	$	388,614		$	564,230		$	374,102		$	535,920
Additions	92,511			140,548			167,782			258,441
Recognition of deferred revenue	(67,878		)	(97,515		)	(128,637		)	(187,098		)
Ending balance	$	413,247		$	607,263		$	413,247		$	607,263

____________________________________

⁽¹⁾ Balance as of January 31, 2018 was adjusted to reflect the adoption of ASC 606.

Financial Instruments - (Tables)

6 Months Ended

Jul. 31, 2019

Investments, Debt and Equity Securities [Abstract]

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, 2019 and July 31, 2019 (in thousands):



	As of January 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash Equivalents		Marketable Securities		Restricted Cash
Level 1
Money market accounts	$	—	$	—	$	—		$	43,038	$	27,215	$	—	$	15,823
Level 2
U.S. government treasury notes	315,329		208		(315		)	315,222		34,129		281,093		—
U.S. government agencies	69,114		17		(154		)	68,977		9,983		58,994		—
Corporate debt securities	363,860		534		(757		)	363,637		—		363,637		—
Foreign government bonds	7,965		36		—			8,001		—		8,001		—
Asset-backed securities	37,664		105		(12		)	37,757		—		37,757		—
Total	$	793,932	$	900	$	(1,238	)	$	836,632	$	71,327	$	749,482	$	15,823



	As of July 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash Equivalents		Marketable Securities		Restricted Cash
Level 1
Money market accounts	$	—	$	—	$	—		$	36,659	$	21,234	$	—	$	15,425
Level 2
U.S. government treasury notes	348,463		1,454		(58		)	349,859		—		349,859		—
U.S. government agencies	66,153		222		(22		)	66,353		—		66,353		—
Corporate debt securities	427,362		2,685		(111		)	429,936		1,029		428,907		—
Foreign government bonds	8,480		100		—			8,580		—		8,580		—
Asset-backed securities	59,504		329		(11		)	59,822		—		59,822		—
Total	$	909,962	$	4,790	$	(202	)	$	951,209	$	22,263	$	913,521	$	15,425

Amortized Cost and Estimated Fair Value

The amortized cost and estimated fair value of our marketable securities are shown below by contractual maturity (in thousands):



	As of July 31, 2019
	Amortized Cost		Fair Value
Due within one year	$	336,156	$	336,736
Due in one to five years	572,777		576,785
Total	$	908,933	$	913,521

Gross Unrealized Losses and Fair Values

The following table presents gross unrealized losses and fair values for those investments that were in a continuous unrealized loss position as of July 31, 2019, aggregated by investment category (in thousands):



	Less than 12 months					Greater than 12 months					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
U.S. government treasury notes	$	27,887	$	(30	)	$	9,737	$	(28	)	$	37,624	$	(58	)
U.S. government agencies	5,215		(7		)	9,183		(15		)	14,398		(22		)
Corporate debt securities	38,856		(28		)	43,245		(83		)	82,101		(111		)
Asset-backed securities	9,399		(11		)	—		—			9,399		(11		)
Total	$	81,357	$	(76	)	$	62,165	$	(126	)	$	143,522	$	(202	)

Balance Sheet Components - (Tables)

6 Months Ended

Jul. 31, 2019

Balance Sheet Components Disclosure [Abstract]

Inventory

Inventory consists of the following (in thousands):



	As of January 31, 2019		As of July 31, 2019
Raw materials	$	3,349	$	2,623
Finished goods	41,338		33,197
Inventory	$	44,687	$	35,820

Property and Equipment, Net

Property and equipment, net consists of the following (in thousands):



	As of January 31, 2019			As of July 31, 2019
Test equipment	$	170,930		$	191,846
Computer equipment and software	117,330			135,178
Furniture and fixtures	6,980			7,732
Leasehold improvements	34,286			37,866
Total property and equipment	329,526			372,622
Less: accumulated depreciation and amortization	(204,173		)	(241,574		)
Property and equipment, net	$	125,353		$	131,048

Intangible Assets, Net

Intangible assets, net consist of the following (in thousands):



	As of January 31, 2019							As of July 31, 2019
	Gross Carrying Value		Accumulated Amortization			Net Carrying Amount		Gross Carrying Value		Accumulated Amortization			Net Carrying Amount
Technology patents	$	10,125	$	(6,572	)	$	3,553	$	19,125	$	(7,538	)	$	11,587
Developed technology	17,700		(1,135		)	16,565		56,100		(4,028		)	52,072
Intangible assets, net	$	27,825	$	(7,707	)	$	20,118	$	75,225	$	(11,566	)	$	63,659

Expected Amortization Expenses for Intangible Assets

As of July 31, 2019, future expected amortization expense for intangible assets is as follows (in thousands):



Fiscal Years Ending January 31,	Estimated Future Amortization Expense
Remainder of 2020	$	5,402
2021	10,804
2022	9,846
2023	9,300
2024	9,300
Thereafter	19,007
Total	$	63,659

Goodwill

The change in the carrying amount of goodwill is as follows (in thousands):



	Amount
Balance as of January 31, 2019	$	10,997
Goodwill acquired	25,423
Balance as of July 31, 2019	$	36,420

Accrued Expenses and Other Liabilities

Accrued expenses and other liabilities consist of the following (in thousands):



	As of January 31, 2019		As of July 31, 2019
Taxes payable	$	7,146	$	4,967
Accrued marketing	6,173		11,005
Accrued travel and entertainment expenses	3,570		3,055
Acquisition consideration held back	3,725		3,725
Other accrued liabilities	19,246		21,938
Total accrued expenses and other liabilities	$	39,860	$	44,690

Convertible Senior Notes - (Tables)

6 Months Ended

Jul. 31, 2019

Debt Disclosure [Abstract]

Convertible Debt

The Notes consisted of the following (in thousands):



	As of July 31, 2019
Liability:
Principal	$	575,000
Less: debt discount, net of amortization	(104,329		)
Less: debt issuance costs, net of amortization	(7,553		)
Net carrying amount of the Notes	$	463,118

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 three and six months ended July 31, 2018 and 2019 (in thousands):



	Three Months Ended July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Amortization of debt discount	$	6,000		$	6,341		$	7,357		$	12,393
Amortization of debt issuance costs	434			459			532			897
Total amortization of debt discount and debt issuance costs	6,434			6,800			7,889			13,290
Contractual interest expense	181			181			224			358
Total interest expense related to the Notes	$	6,615		$	6,981		$	8,113		$	13,648

Effective interest rate of the liability component	5.6		%	5.6		%	5.6		%	5.6		%

Leases - (Tables)

6 Months Ended

Jul. 31, 2019

Leases [Abstract]

Lease costs

Supplemental cash flow information related to our operating leases for the six months ended July 31, 2019 as well as the weighted-average remaining lease term and weighted-average discount rate as of July 31, 2019 were as follows:



Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$	16,167
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$	3,449
Weighted-average remaining lease term (years)	5.28
Weighted-average discount rate	6.46		%

The components of lease costs were as follows (in thousands):



	Three Months Ended		Six Months Ended
	July 31, 2019		July 31, 2019
Fixed operating lease cost	$	8,228	$	16,711
Variable lease cost ⁽¹⁾	2,242		4,342
Short-term lease cost (12 months or less)	1,484		2,345
Total lease cost	$	11,954	$	23,398

——————————

⁽¹⁾Variable lease cost for the three and six months ended July 31, 2019 predominantly includes common area maintenance charges.

Future minimum lease payments

Future lease payments under our non-cancelable operating leases as of July 31, 2019 were as follows (in thousands):



Fiscal Years Ending January 31,	Operating Leases
The remainder of 2020	$	16,579
2021	33,269
2022	26,781
2023	21,478
2024	15,434
Thereafter	31,236
Total future lease payments	144,777
Less: imputed interest	(23,831		)
Present value of lease liabilities	$	120,946

Schedule of future minimum rental payments for operating leases

As previously disclosed in our Annual Report on Form 10-K for the year ended January 31, 2019 and under the previous lease accounting standard, ASC 840, Leases, the following table summarizes the future minimum lease payments due under operating leases as of January 31, 2019 (in thousands):



Year Ending January 31,	Operating Leases
2020	$	31,297
2021	28,573
2022	24,381
2023	20,440
2024	14,780
Thereafter	30,096
Total	$	149,567

Equity Incentive Plans - (Tables)

6 Months Ended

Jul. 31, 2019

Share-based Payment Arrangement [Abstract]

Equity Incentive Plans

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, 2019	35,465,543		$	8.34	5.4	$	339,591
Options exercised	(3,862,965	)	4.99
Options forfeited/canceled	(343,662	)	15.49
Balance as of July 31, 2019	31,258,916		$	8.67	3.9	$	218,450
Vested and exercisable as of July 31, 2019	25,407,263		$	7.54	4.8	$	203,215

Restricted Stock Units

A summary of the RSU activity under our 2015 Plan and related information is as follows:



	Number of RSUs Outstanding		Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Unvested balance as of January 31, 2019	21,917,550		$	17.94	$	392,515
Granted	8,792,982		19.81
Vested	(4,352,885	)	16.38
Forfeited	(1,324,694	)	18.47
Unvested balance as of July 31, 2019	25,032,953		$	18.84	$	378,999

Restricted Stock

A summary of the restricted stock activity under our 2015 Plan and related information is as follows:



	Number of Restricted Stock Outstanding		Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Unvested balance as of January 31, 2019	2,267,569		$	18.70	$	40,612
Granted	1,399,688		20.30
Vested	(843,321	)	19.85
Unvested balance as of July 31, 2019	2,823,936		$	19.25	$	42,754

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 July 31,				Six Months Ended July 31,
	2018		2019		2018		2019
Cost of revenue—product	$	720	$	954	$	1,328	$	1,931
Cost of revenue—support subscription	2,929		3,633		5,613		7,584
Research and development	22,232		29,108		43,322		57,353
Sales and marketing	17,269		16,055		31,209		34,369
General and administrative	10,504		8,654		16,137		19,324
Total stock-based compensation expense	$	53,654	$	58,404	$	97,609	$	120,561

Net Loss per Share Attributable to Common Stockholders - (Tables)

6 Months Ended

Jul. 31, 2019

Earnings Per Share [Abstract]

Net Loss per Share

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 July 31,						Six Months Ended July 31,
	2018			2019			2018			2019

Net loss	$	(60,123	)	$	(66,018	)	$	(124,427	)	$	(166,354	)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	229,359			251,298			226,609			248,366
Net loss per share attributable to common stockholders, basic and diluted	$	(0.26	)	$	(0.26	)	$	(0.55	)	$	(0.67	)

Shares Excluded

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 July 31,		Six Months Ended July 31,
	2018	2019	2018	2019
Stock options to purchase common stock	40,920	31,739	42,923	32,852
Unvested RSUs	19,957	25,513	19,486	24,743
Restricted stock and early exercised stock options subject to repurchase	3,327	2,917	2,585	2,777
Shares related to Notes	21,884	21,884	13,783	21,884
Shares issuable pursuant to ESPP	1,154	720	1,127	720
Total	87,242	82,773	79,904	82,976

Other Income (Expense), Net - (Tables)

6 Months Ended

Jul. 31, 2019

Other Income and Expenses [Abstract]

Other Income

Other income (expense), net consists of the following (in thousands):



	Three Months Ended July 31,						Six Months Ended July 31,
	2018			2019			2018			2019
Interest income ⁽¹⁾	$	4,783		$	6,772		$	6,654		$	13,606
Interest expense ⁽²⁾	(6,615		)	(6,981		)	(8,113		)	(13,648		)
Foreign currency transactions losses	(2,273		)	(443		)	(4,407		)	(2,426		)
Other income	73			—			835			—
Total other income (expense), net	$	(4,032	)	$	(652	)	$	(5,031	)	$	(2,468	)

____________________________________

⁽¹⁾Interest income includes interest income related to our cash, cash equivalents and marketable securities and non-cash interest income related to accretion (amortization) of the discount (premium) on marketable securities.

⁽²⁾ Interest expense includes non-cash interest expense related to amortization of the debt discount and debt issuance costs and the contractual interest expense related to the Notes for the three and six months ended July 31, 2018 and 2019.

Segment Information - (Tables)

6 Months Ended

Jul. 31, 2019

Segment Reporting [Abstract]

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 July 31,				Six Months Ended July 31,
	2018		2019		2018		2019

United States	$	229,760	$	294,596	$	414,678	$	523,535
Rest of the world	79,124		101,731		150,151		199,492
Total revenue	$	308,884	$	396,327	$	564,829	$	723,027

Long-Lived Assets by Geographic Area

assets, which are comprised of property and equipment, net, by geographic area are summarized as follows (in thousands):



	As of January 31, 2019		As of July 31, 2019

United States	$	120,876	$	121,454
Rest of the world	4,477		9,594
Total long-lived assets	$	125,353	$	131,048

Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018	Apr. 30, 2019	Feb. 01, 2019	Jan. 31, 2019	Apr. 30, 2018	Jan. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred commissions	$ 118,568	$ 91,469	$ 118,568	$ 91,469	$ 86,044		$ 114,973	$ 113,257	$ 87,313
Revenue recognition over next 12 months, percent	41.00%		41.00%
Operating lease right-of-use assets	$ 114,339		$ 114,339				0
Operating lease liabilities	120,946		120,946
Restricted cash	15,425	15,778	15,425	15,778			$ 15,823
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets						$ 124,500
Operating lease liabilities						$ 130,600
Product Revenue and Support Subscription Revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue recognized	$ 88,200	$ 60,900	$ 150,200	$ 106,200

- Deferred Commissions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
- Deferred Commissions (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Accounting Policies [Abstract]
Remaining amortization period	6 years		6 years
Contract Assets
Beginning balance	$ 86,044	$ 113,257	$ 114,973	$ 87,313
Additions	30,074	24,582	48,310	40,003
Recognition of deferred commissions	(24,763)	(19,157)	(44,715)	(35,847)
Ending balance	$ 118,568	$ 91,469	$ 118,568	$ 91,469

- Deferred Commissions (Typed Dimensions) (Details)	Jul. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-08-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation (as a percent)	26.00%

Basis of Presentation and Summary of Significant Accounting Policies - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Contract Liability
Beginning balance	$ 564,230	$ 388,614	$ 535,920	$ 374,102
Additions	140,548	92,511	258,441	167,782
Recognition of deferred revenue	97,515	(67,878)	(187,098)	(128,637)
Ending balance	607,263	413,247	607,263	413,247
Product Revenue and Support Subscription Revenue
Contract Liability
Ending balance	770,100		770,100
Deferred revenue recognized	$ 88,200	$ 60,900	$ 150,200	$ 106,200

Financial Instruments - Cash Equivalents, Marketable Securities and Restricted Cash (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 909,962	$ 793,932
Amortized Cost	908,933
Gross Unrealized Gains	4,790	900
Gross Unrealized Losses	(202)	(1,238)
Fair Value	951,209	836,632
Fair Value	913,521
Cash Equivalents	22,263	71,327
Marketable Securities	913,521	749,482
Restricted Cash	15,425	15,823
Level 1 \| Money market accounts
Debt Securities, Available-for-sale [Line Items]
Fair Value	36,659	43,038
Cash Equivalents	21,234	27,215
Marketable Securities	0	0
Restricted Cash	15,425	15,823
Level 2 \| U.S. government treasury notes
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	348,463	315,329
Gross Unrealized Gains	1,454	208
Gross Unrealized Losses	(58)	(315)
Fair Value	349,859	315,222
Cash Equivalents	0	34,129
Marketable Securities	349,859	281,093
Restricted Cash	0	0
Level 2 \| U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	66,153	69,114
Gross Unrealized Gains	222	17
Gross Unrealized Losses	(22)	(154)
Fair Value	66,353	68,977
Cash Equivalents	0	9,983
Marketable Securities	66,353	58,994
Restricted Cash	0	0
Level 2 \| Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	427,362	363,860
Gross Unrealized Gains	2,685	534
Gross Unrealized Losses	(111)	(757)
Fair Value	429,936	363,637
Cash Equivalents	1,029	0
Marketable Securities	428,907	363,637
Restricted Cash	0	0
Level 2 \| Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,480
Amortized Cost		7,965
Gross Unrealized Gains	100
Gross Unrealized Gains		36
Gross Unrealized Losses	0
Gross Unrealized Losses		0
Fair Value	8,580
Fair Value		8,001
Cash Equivalents	0	0
Marketable Securities	8,580	8,001
Restricted Cash	0	0
Level 2 \| Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	59,504
Amortized Cost		37,664
Gross Unrealized Gains	329
Gross Unrealized Gains		105
Gross Unrealized Losses	(11)
Gross Unrealized Losses		(12)
Fair Value	59,822
Fair Value		37,757
Cash Equivalents	0	0
Marketable Securities	59,822	37,757
Restricted Cash	$ 0	$ 0

Financial Instruments - Amortized Cost and Estimated Fair Value (Details) $ in Thousands	Jul. 31, 2019 USD ($)
Amortized Cost
Due within one year	$ 336,156
Due in one to five years	572,777
Total	908,933
Fair Value
Due within one year	336,736
Due in one to five years	576,785
Total	$ 913,521

Financial Instruments - Gross Unrealized Losses and Fair Values (Details) $ in Thousands	Jul. 31, 2019 USD ($)
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	$ 81,357
Unrealized Loss, Less than 12 Months	(76)
Fair Value, Greater than 12 months	62,165
Unrealized Loss, Greater than 12 months	(126)
Fair Value, Total	143,522
Unrealized Loss, Total	(202)
U.S. government treasury notes
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	27,887
Unrealized Loss, Less than 12 Months	(30)
Fair Value, Greater than 12 months	9,737
Unrealized Loss, Greater than 12 months	(28)
Fair Value, Total	37,624
Unrealized Loss, Total	(58)
U.S. government agencies
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	5,215
Unrealized Loss, Less than 12 Months	(7)
Fair Value, Greater than 12 months	9,183
Unrealized Loss, Greater than 12 months	(15)
Fair Value, Total	14,398
Unrealized Loss, Total	(22)
Corporate debt securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	38,856
Unrealized Loss, Less than 12 Months	(28)
Fair Value, Greater than 12 months	43,245
Unrealized Loss, Greater than 12 months	(83)
Fair Value, Total	82,101
Unrealized Loss, Total	(111)
Asset-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Fair Value, Less than 12 months	9,399
Unrealized Loss, Less than 12 Months	(11)
Fair Value, Greater than 12 months	0
Unrealized Loss, Greater than 12 months	0
Fair Value, Total	9,399
Unrealized Loss, Total	$ (11)

Business Combination - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended
	Jun. 30, 2019	Apr. 30, 2019	Jul. 31, 2019	Jan. 31, 2019
Business Acquisition [Line Items]
Goodwill			$ 36,420	$ 10,997
Acquisition consideration held back			3,725	$ 3,725
Compuverde AB
Business Acquisition [Line Items]
Acquisition Related Costs		$ 500
Cash consideration transferred		$ 47,900
Long-term debt assumed and subsequently paid off			11,600
Goodwill			25,400
Net liabilities assumed			10,200
Deferred tax liabilities assumed			5,700
Acquisition Costs			15,900
Compuverde AB \| Restricted Stock Units
Business Acquisition [Line Items]
Equity interests issued and issuable	$ 3,000
Compuverde AB \| Developed technology
Business Acquisition [Line Items]
Finite-lived intangibles acquired			$ 38,400
Useful Life (in years)		7 years

Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Balance Sheet Components Disclosure [Abstract]
Raw materials	$ 2,623	$ 3,349
Finished goods	33,197	41,338
Inventory	$ 35,820	$ 44,687

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Property Plant And Equipment [Line Items]
Total property and equipment	$ 372,622	$ 329,526
Less: accumulated depreciation and amortization	(241,574)	(204,173)
Property and equipment, net	131,048	125,353
Test equipment
Property Plant And Equipment [Line Items]
Total property and equipment	191,846	170,930
Computer equipment and software
Property Plant And Equipment [Line Items]
Total property and equipment	135,178	117,330
Furniture and fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	7,732	6,980
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 37,866	$ 34,286

Balance Sheet Components - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Balance Sheet Components Disclosure [Abstract]
Depreciation and amortization	$ 19.9	$ 16.8	$ 32.8	$ 39.7
Intangible assets amortization expense	$ 2.6	$ 0.4	$ 3.9	$ 0.8
Technology patents
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining useful life (in years)	7 years		4 years 2 months 12 days
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining useful life (in years)			6 years 6 months

Balance Sheet Components - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2019	Jul. 31, 2019	Jan. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 75,225	$ 75,225	$ 27,825
Accumulated Amortization	(11,566)	(11,566)	(7,707)
Net Carrying Amount	63,659	63,659	20,118
Technology patents
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Residual Value	9,000	9,000
Gross Carrying Value	19,125	19,125	10,125
Accumulated Amortization	(7,538)	(7,538)	(6,572)
Net Carrying Amount	$ 11,587	$ 11,587	3,553
Weighted-average remaining useful life (in years)	7 years	4 years 2 months 12 days
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 56,100	$ 56,100	17,700
Accumulated Amortization	(4,028)	(4,028)	(1,135)
Net Carrying Amount	$ 52,072	$ 52,072	$ 16,565
Weighted-average remaining useful life (in years)		6 years 6 months

Balance Sheet Components - Expected Amortization Expenses for Intangible Assets (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Balance Sheet Components Disclosure [Abstract]
Remainder of 2020	$ 5,402
2021	10,804
2022	9,846
2023	9,300
2024	9,300
Thereafter	19,007
Net Carrying Amount	$ 63,659	$ 20,118

Balance Sheet Components - Goodwill (Details) $ in Thousands	6 Months Ended
	Jul. 31, 2019 USD ($)
Goodwill [Roll Forward]
January 31, 2019	$ 10,997
Goodwill acquired	25,423
July 31, 2019	$ 36,420

Balance Sheet Components - Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Balance Sheet Components Disclosure [Abstract]
Taxes payable	$ 4,967	$ 7,146
Accrued marketing	11,005	6,173
Accrued travel and entertainment expenses	3,055	3,570
Acquisition consideration held back	3,725	3,725
Other accrued liabilities	21,938	19,246
Total accrued expenses and other liabilities	$ 44,690	$ 39,860

Convertible Senior Notes - Narrative (Details)	1 Months Ended	6 Months Ended
Convertible Senior Notes - Narrative (Details)	Apr. 30, 2018 USD ($) day shares $ / shares	Jul. 31, 2019 USD ($) $ / shares	Jul. 31, 2018 USD ($)	Apr. 04, 2018 $ / shares
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes, net of issuance costs		$ 0	$ 562,062,000
Debt issuance costs, net of amortization	$ 12,900,000
Closing price of stock (in dollars per share) \| $ / shares		$ 15.14
Payment for purchase of capped calls		$ 0	64,630,000
Capped Call
Debt Instrument [Line Items]
Payment for purchase of capped calls	64,600,000
Convertible Senior Notes
Debt Instrument [Line Items]
Debt issuance costs, net of amortization	9,800,000	7,553,000
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]
Conversion price (in dollars per share) \| $ / shares	$ 26.27
Closing price of stock (in dollars per share) \| $ / shares		$ 15.14		$ 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	$ 575,000,000.0		$ 575,000,000.0
Interest rate (as a percent)	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		$ 558,700,000
If-converted value		$ 331,300,000
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

Convertible Senior Notes - Convertible Debt (Details) - USD ($) $ in Thousands		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Apr. 30, 2018
Liability:
Less: debt issuance costs, net of amortization			$ (12,900)
Stockholders' equity:
Allocated value of the conversion feature		$ 133,265
Less: debt issuance costs			(12,900)
Convertible Senior Notes
Liability:
Principal	$ 575,000
Less: debt discount, net of amortization	(104,329)
Less: debt issuance costs, net of amortization	(7,553)		(9,800)
Net carrying amount of the Notes	463,118
Stockholders' equity:
Less: debt issuance costs	(7,553)		(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 - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Debt Instrument [Line Items]
Total amortization of debt discount and debt issuance costs			$ 13,290	$ 7,889
Convertible Senior Notes
Debt Instrument [Line Items]
Amortization of debt discount	$ 6,341	$ 6,000	12,393	7,357
Amortization of debt issuance costs	459	434	897	532
Total amortization of debt discount and debt issuance costs	6,800	6,434	13,290	7,889
Contractual interest expense	181	181	358	224
Total interest expense related to the Notes	$ 6,981	$ 6,615	$ 13,648	$ 8,113
Effective interest rate of the liability component	5.60%	5.60%	5.60%	5.60%

Commitments and Contingencies - Narrative (Details) - USD ($)	Jul. 31, 2019	Jan. 31, 2019	Jul. 31, 2018	Apr. 30, 2018
Lessee, Lease, Description [Line Items]
Outstanding letters of credit	$ 11,600,000	$ 10,800,000
Letter of Credit
Lessee, Lease, Description [Line Items]
Principal amount		$ 500,000
Convertible Senior Notes
Lessee, Lease, Description [Line Items]
Principal amount			$ 575,000,000.0	$ 575,000,000.0

Leases - Lease costs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Leases - Lease costs (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jul. 31, 2019
Leases [Abstract]
Fixed operating lease cost	$ 8,228	$ 16,711
Variable lease cost	2,242	4,342
Short-term lease cost (12 months or less)	1,484	2,345
Total lease cost	$ 11,954	$ 23,398

Leases - Future minimum lease payments (Details) $ in Thousands	Jul. 31, 2019 USD ($)
Leases [Abstract]
The remainder of 2020	$ 16,579
2021	33,269
2022	26,781
2023	21,478
2024	15,434
Thereafter	31,236
Total future lease payments	144,777
Less: imputed interest	(23,831)
Present value of lease liabilities	$ 120,946

Leases - Lease cash flow information (Details) $ in Thousands	6 Months Ended
	Jul. 31, 2019 USD ($)
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 16,167
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 3,449
Weighted-average remaining lease term (years)	5 years 3 months 10 days
Weighted-average discount rate (as a percent)	6.46%

Leases - Schedule Aggregate Future Minimum Payments Under Non-Cancelable Operating Leases (Details) $ in Thousands	Jan. 31, 2019 USD ($)
Leases [Abstract]
2020	$ 31,297
2021	28,573
2022	24,381
2023	20,440
2024	14,780
Thereafter	30,096
Total future lease payments	$ 149,567

Stockholders' Equity - Narrative (Details)	1 Months Ended
Stockholders' Equity - Narrative (Details)	Apr. 30, 2018 USD ($) shares	Aug. 31, 2019 USD ($)	Jul. 31, 2019 class $ / shares shares	Jan. 31, 2019 $ / shares shares	Apr. 04, 2018 $ / shares
Equity [Abstract]
Shares authorized (in shares)			20,000,000	20,000,000
Number of classes of stock \| class			2
Class of Stock [Line Items]
Shares authorized (in shares)			2,250,000,000	2,250,000,000
Par value per share (in dollars per share) \| $ / shares			$ 0.0001	$ 0.0001
Shares issued (in shares)			241,359,000	220,979,000
Closing price of stock (in dollars per share) \| $ / shares			$ 15.14
Class A
Class of Stock [Line Items]
Shares authorized (in shares)			2,000,000,000	2,000,000,000
Par value per share (in dollars per share) \| $ / shares			$ 0.0001	$ 0.0001
Shares issued (in shares)			255,751,711	243,524,000
Stock repurchased and retired (in shares)	1,008,573
Stock repurchased and retired during period, value \| $	$ 20,000,000.0
Closing price of stock (in dollars per share) \| $ / shares			$ 15.14		$ 19.83
Class B
Class of Stock [Line Items]
Shares authorized (in shares)			250,000,000	250,000,000
Par value per share (in dollars per share) \| $ / shares			$ 0.0001	$ 0.0001
Shares issued (in shares)			0	0
Subsequent Event \| Class A
Class of Stock [Line Items]
Value Approved For Repurchase \| $		$ 150,000,000.0

Equity Incentive Plans - Narrative (Details)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
Equity Incentive Plans - Narrative (Details)	Mar. 16, 2016	Feb. 28, 2019 USD ($)	Jul. 31, 2019 USD ($) $ / shares	Jul. 31, 2018 USD ($)	Jul. 31, 2019 USD ($) plan $ / shares	Jul. 31, 2018 USD ($)	Dec. 31, 2015 USD ($) period shares	Apr. 04, 2018 $ / shares
Share-based Payment Arrangement [Abstract]
Number of equity incentive plans \| plan					2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of stock (in dollars per share) \| $ / shares			$ 15.14		$ 15.14
Total stock-based compensation expense			$ 58,404,000	$ 53,654,000	$ 120,561,000	$ 97,609,000
Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of stock (in dollars per share) \| $ / shares			$ 15.14		$ 15.14			$ 19.83
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			$ 4,200,000	7,900,000	$ 15,700,000	14,600,000
Unrecognized stock-based compensation expense			19,400,000		$ 19,400,000
Compensation cost (in years)					1 year 6 months
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
Dollar cap per purchase period		$ 7,500
Modification charges					$ 2,200,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense			7,400,000	$ 6,700,000	14,800,000	$ 10,200,000
Unrecognized stock-based compensation expense			$ 30,600,000		$ 30,600,000
Compensation cost (in years)					2 years 3 months 18 days

Equity Incentive Plans - Equity Incentive Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 31, 2019	Jan. 31, 2019	Apr. 04, 2018
Options Outstanding, Number of Shares
Beginning balance (in shares)	35,465,543
Options exercised (in shares)	(3,862,965)
Options forfeited/cancelled (in shares)	(343,662)
Ending balance (in shares)	31,258,916	35,465,543
Vested and exercisable (in shares)	25,407,263
Options Outstanding, Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 8.34
Options exercised (in dollars per share)	4.99
Options forfeited/cancelled (in dollars per share)	15.49
Ending balance (in dollars per share)	8.67	$ 8.34
Weighted Average Exercise Price, Vested and exercisable (in dollars per share)	$ 7.54
Weighted- Average Remaining Contractual Life
Weighted Average Remaining Contractual Life (in years)	3 years 10 months 24 days	5 years 4 months 24 days
Weighted Average Remaining Contractual Life, Vested and exercisable (in years)	4 years 9 months 18 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 218,450	$ 339,591
Aggregate Intrinsic Value, Vested and exercisable	$ 203,215
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of stock (in dollars per share)	$ 15.14
Unrecognized compensation cost, stock options	$ 20,600
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost (in years)	1 year 7 months 6 days
Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of stock (in dollars per share)	$ 15.14		$ 19.83
2015 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost (in years)	1 year 6 months

Equity Incentive Plans - Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Weighted-Average Grant Date Fair Value
Stock-based compensation expense		$ 58,404	$ 53,654	$ 120,561	$ 97,609
Restricted Stock Units
Number of Restricted Stock Units Outstanding
Unvested, Beginning balance (in shares)				21,917,550
Granted (in shares)				8,792,982
Vested (in shares)				(4,352,885)
Forfeited (in shares)				(1,324,694)
Unvested, Ending balance (in shares)	21,917,550	25,032,953		25,032,953
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 17.94
Granted (in dollars per share)				19.81
Vested (in dollars per share)				16.38
Forfeited (in dollars per share)				18.47
Ending balance (in dollars per share)	$ 17.94	$ 18.84		$ 18.84
Aggregate Intrinsic Value	$ 392,515	$ 378,999		$ 378,999
Share-based compensation expense		40,400	29,500	77,700	55,900
Compensation not yet recognized		$ 427,800		$ 427,800
Compensation cost (in years)				3 years
Restricted Stock
Number of Restricted Stock Units Outstanding
Unvested, Beginning balance (in shares)				2,267,569
Vested (in shares)				(843,321)
Unvested, Ending balance (in shares)	2,267,569	2,823,936		2,823,936
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 18.70
Vested (in dollars per share)				19.85
Ending balance (in dollars per share)	$ 18.70	$ 19.25		$ 19.25
Aggregate Intrinsic Value	$ 40,612	$ 42,754		$ 42,754
Compensation cost (in years)				2 years 3 months 18 days
Stock-based compensation expense		$ 7,400	$ 6,700	$ 14,800	$ 10,200
Previously Issued Performance Awards \| Restricted Stock
Number of Restricted Stock Units Outstanding
Granted (in shares)		108,494

Equity Incentive Plans - Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 58,404	$ 53,654	$ 120,561	$ 97,609
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issued (in shares)				8,792,982
Compensation cost (in years)				3 years
Number of Restricted Stock Outstanding
Unvested, Beginning balance (in shares)				21,917,550
Vested (in shares)				(4,352,885)
Unvested, Ending balance (in shares)	21,917,550	25,032,953		25,032,953
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 17.94
Vested (in dollars per share)				16.38
Ending balance (in dollars per share)	$ 17.94	$ 18.84		$ 18.84
Aggregate Intrinsic Value	$ 392,515	$ 378,999		$ 378,999
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		7,400	$ 6,700	14,800	$ 10,200
Unrecognized stock-based compensation expense		$ 30,600		$ 30,600
Compensation cost (in years)				2 years 3 months 18 days
Number of Restricted Stock Outstanding
Unvested, Beginning balance (in shares)				2,267,569
Granted and converted (in shares)				1,399,688
Vested (in shares)				(843,321)
Unvested, Ending balance (in shares)	2,267,569	2,823,936		2,823,936
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 18.70
Granted and converted (in dollars per share)				20.30
Vested (in dollars per share)				19.85
Ending balance (in dollars per share)	$ 18.70	$ 19.25		$ 19.25
Aggregate Intrinsic Value	$ 40,612	$ 42,754		$ 42,754
Restricted Stock \| Performance Vesting at Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issued (in shares)	183,902	60,716		1,291,194
Award vesting rights (as a percent)	100.00%
Restricted Stock \| Maximum \| Performance Vesting at Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)	160.00%
Restricted Stock \| Minimum \| Performance Vesting at Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)	0.00%

Equity Incentive Plans - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 58,404	$ 53,654	$ 120,561	$ 97,609
Cost of revenue—product
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	954	720	1,931	1,328
Cost of revenue—support subscription
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	3,633	2,929	7,584	5,613
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	29,108	22,232	57,353	43,322
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	16,055	17,269	34,369	31,209
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,654	$ 10,504	$ 19,324	$ 16,137

Net Loss per Share Attributable to Common Stockholders - Net Loss per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (66,018)	$ (60,123)	$ (166,354)	$ (124,427)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	251,298	229,359	248,366	226,609
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.26)	$ (0.26)	$ (0.67)	$ (0.55)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Net Loss per Share Attributable to Common Stockholders - Shares Excluded (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	82,773	87,242	82,976	79,904
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)	31,739	40,920	32,852	42,923
Unvested RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	25,513	19,957	24,743	19,486
Restricted stock and early exercised stock options subject to repurchase
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	2,917	3,327	2,777	2,585
Shares issuable pursuant to ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	720	1,154	720	1,127
Shares related to Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	21,884	21,884	21,884	13,783

Other Income (Expense), Net - Other Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Other Income and Expenses [Abstract]
Interest income	$ 6,772	$ 4,783	$ 13,606	$ 6,654
Interest expense	(6,981)	(6,615)	(13,648)	(8,113)
Foreign currency transactions losses	(443)	(2,273)	(2,426)	(4,407)
Other income	0	73	0	835
Total other income (expense), net	$ (652)	$ (4,032)	$ (2,468)	$ (5,031)

Segment Information - Narrative (Details)	6 Months Ended
Segment Information - Narrative (Details)	Jul. 31, 2019 segment
Segment Reporting [Abstract]
Number of business activities	1
Number of reportable segments	1

Segment Information - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 396,327	$ 308,884	$ 723,027	$ 564,829
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	294,596	229,760	523,535	414,678
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 101,731	$ 79,124	$ 199,492	$ 150,151

Segment Information - Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Revenues From External Customers And Long Lived Assets [Line Items]
Total long-lived assets	$ 131,048	$ 125,353
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total long-lived assets	121,454	120,876
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total long-lived assets	$ 9,594	$ 4,477