Okta (OKTA) 10-Q 7 Sep 18 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jul. 31, 2018	Aug. 31, 2018
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Jul. 31, 2018
Amendment Flag	false
Entity Registrant Name	Okta, Inc.
Entity Central Index Key	1,660,134
Current Fiscal Year End Date	--01-31
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2,019
Document Period Focus	Q2
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		97,147,059
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		12,035,911

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018	[1]
Current assets:
Cash and cash equivalents	$ 192,882	$ 127,949
Short-term investments	343,374	101,765
Accounts receivable, net of allowances of $962 and $1,472	59,839	52,248
Deferred commissions	19,848	17,755
Prepaid expenses and other current assets	17,433	17,781
Total current assets	633,376	317,498
Property and equipment, net	40,670	12,540
Deferred commissions, noncurrent	43,287	40,755
Intangible assets, net	16,006	11,761
Goodwill	18,095	6,282
Other assets	12,483	10,427
Total assets	763,917	399,263
Current liabilities:
Accounts payable	12,577	9,566
Accrued expenses and other current liabilities	6,333	6,187
Accrued compensation	12,803	12,374
Deferred revenue	186,427	159,816
Total current liabilities	218,140	187,943
Convertible senior notes, net	263,762	0
Deferred revenue, noncurrent	5,471	4,963
Other liabilities, noncurrent	31,399	7,017
Total liabilities	518,772	199,923
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, par value $0.0001 per share; 100,000 shares authorized, no shares issued and outstanding as of July 31, 2018 and January 31, 2018.	0	0
Additional paid-in capital	677,497	565,653
Accumulated other comprehensive income (loss)	(480)	391
Accumulated deficit	(431,883)	(366,714)
Total stockholders’ equity	245,145	199,340
Total liabilities and stockholders’ equity	763,917	399,263
Class A Common Stock
Stockholders’ equity:
Common stock	10	7
Class B Common Stock
Stockholders’ equity:
Common stock	$ 1	$ 3
[1]	See Note 2 for a summary of adjustments.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018
Statement of Financial Position [Abstract]
Allowance for accounts receivable	$ 962	$ 1,472
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock
Common stock par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	96,680,000	70,610,000
Common stock, shares outstanding (in shares)	96,680,000	70,610,000
Class B Common Stock
Common stock par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	12,314,000	33,361,000
Common stock, shares outstanding (in shares)	12,314,000	33,361,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	[1]	Jul. 31, 2018	Jul. 31, 2017	[1]
Revenue:
Subscription	$ 87,854	$ 55,317		$ 164,695	$ 103,596
Professional services and other	6,732	4,942		13,512	8,988
Total revenue	94,586	60,259		178,207	112,584
Cost of revenue:
Subscription	19,211	12,691		35,543	23,848
Professional services and other	9,017	6,991		16,792	13,297
Total cost of revenue	28,228	19,682		52,335	37,145
Gross profit	66,358	40,577		125,872	75,439
Operating expenses:
Research and development	24,829	16,923		44,758	32,282
Sales and marketing	59,004	37,891		108,497	73,194
General and administrative	20,955	11,948		36,025	23,587
Total operating expenses	104,788	66,762		189,280	129,063
Operating loss	(38,430)	(26,185)		(63,408)	(53,624)
Other income (expense), net	(1,762)	382		(2,977)	363
Loss before provision for (benefit from) income taxes	(40,192)	(25,803)		(66,385)	(53,261)
Provision for (benefit from) income taxes	(985)	229		(1,216)	477
Net loss	$ (39,207)	$ (26,032)	[2]	$ (65,169)	$ (53,738)	[3]
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.37)	$ (0.28)		$ (0.62)	$ (0.80)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (in shares)	106,702	93,576		105,475	67,125
[1]	See Note 2 for a summary of adjustments.
[2]	See Note 2 for a summary of adjustments.
[3]	See Note 2 for a summary of adjustments.

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	[2]	Jul. 31, 2018	Jul. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (39,207)	$ (26,032)	[1]	$ (65,169)	$ (53,738)	[1],[3]
Other comprehensive income (loss):
Net change in unrealized losses on available-for-sale securities	77	(12)		(48)	(12)	[2]
Foreign currency translation adjustments	(379)	181		(823)	249	[2]
Other comprehensive income (loss)	(302)	169		(871)	237	[2]
Comprehensive loss	$ (39,509)	$ (25,863)		$ (66,040)	$ (53,501)	[2]
[1]	See Note 2 for a summary of adjustments.
[2]	See Note 2 for a summary of adjustments.
[3]	See Note 2 for a summary of adjustments.

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	[2]
Cash flows from operating activities:
Net loss	$ (65,169)	$ (53,738)	[1]
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	32,357	20,884
Depreciation, amortization and accretion	3,699	3,288
Amortization of debt discount and issuance costs	6,413	0
Amortization of deferred commissions	9,613	7,006
Deferred income taxes	(1,575)	0
Non-cash charitable contributions	1,008	0
Other	18	689
Changes in operating assets and liabilities, net of business combination:
Accounts receivable	(7,240)	(1,311)
Deferred commissions	(14,240)	(9,517)
Prepaid expenses and other assets	(800)	(4,900)
Accounts payable	2,557	2,732
Accrued compensation	498	2,562
Accrued expenses and other liabilities	4,679	(1,601)
Deferred revenue	26,811	17,982
Net cash used in operating activities	(1,371)	(15,924)
Cash flows from investing activities:
Capitalization of internal-use software costs	(1,725)	(2,743)
Purchases of property and equipment	(9,790)	(5,156)
Purchases of securities available for sale	(320,018)	(86,776)
Proceeds from maturities of securities available for sale	79,500	12,835
Proceeds from sales of securities available for sale	0	1,538
Payments for business acquisition, net of cash acquired	(15,638)	0
Net cash used in investing activities	(267,671)	(80,302)
Cash flows from financing activities:
Proceeds from initial public offering, net of underwriters' discounts and commissions	0	199,948
Proceeds from issuance of convertible senior notes, net of issuance costs	334,980	0
Purchase of convertible senior notes hedge	(80,040)	0
Proceeds from issuance of warrants related to convertible notes	52,440	0
Payments of deferred offering costs	0	(4,038)
Proceeds from stock option exercises, net of repurchases	21,055	3,916
Proceeds from shares issued in connection with employee stock purchase plan	6,654	0
Other	(206)	(273)
Net cash provided by financing activities	334,883	199,553
Effects of changes in foreign currency exchange rates on cash and cash equivalents	(632)	134
Net increase in cash, cash equivalents and restricted cash	65,209	103,461
Cash, cash equivalents and restricted cash at beginning of period	136,233	23,282
Cash, cash equivalents and restricted cash at end of period	201,442	126,743
Non-cash investing and financing activities:
Vesting of early exercised common stock options	459	693
Issuance of common stock in connection with warrant exercises	0	272
Common stock issued as charitable contribution	1,008	0
Property and equipment acquired through tenant improvement allowance	22,237	0
Property and equipment and other accrued but not yet paid	605	271
Issuance of common stock in connection with business combination	0	2,160
Conversion of redeemable convertible preferred stock to common stock	0	228,362
Reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets to the amounts shown in the statements of cash flows above:
Total cash, cash equivalents and restricted cash	$ 136,233	$ 23,282
[1]	See Note 2 for a summary of adjustments.
[2]	See Note 2 for a summary of adjustments.

Overview and Basis of Presentat

Overview and Basis of Presentation	6 Months Ended
	Jul. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Overview and Basis of Presentation	Overview and Basis of Presentation Description of Business Okta, Inc. (the Company) is the leading independent provider of identity for the enterprise. The Okta Identity Cloud enables the Company’s customers to securely connect people to technology, anywhere, anytime and from any device. The Company was incorporated in January 2009 as Saasure Inc., a California corporation, and was later reincorporated in April 2010 under the name Okta, Inc. as a Delaware corporation. The Company is headquartered in San Francisco, California. Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements, which include the accounts of the Company and its wholly owned subsidiaries, have been prepared in conformity with U.S. generally accepted accounting principles (GAAP). All intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated balance sheet as of January 31, 2018 , included herein, was derived from the audited financial statements as of that date. The unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the balance sheet, statements of operations, statements of comprehensive loss and the statements of cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full fiscal year ending January 31, 2019 or any future period. The Company’s fiscal year ends on January 31. References to fiscal 2019 , for example, refer to the fiscal year ending January 31, 2019 . The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company’s Form 10-K filed with the Securities and Exchange Commission (SEC) on March 12, 2018. Effective February 1, 2018, the Company adopted the requirements of Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers as discussed in Note 2. All amounts and disclosures set forth in this Form 10-Q have been updated to comply with this standard, as indicated by references to "as adjusted" in these condensed consolidated financial statements and related notes. Initial Public Offering In April 2017, the Company completed an initial public offering (IPO), in which the Company issued and sold 12,650,000 shares of its Class A common stock at a public offering price of $17.00 per share. The Company received aggregate proceeds of $200.0 million from the IPO, net of underwriters’ discounts and commissions, before deducting offering costs of approximately $5.6 million . Immediately prior to the completion of the IPO, all shares of common stock then outstanding were reclassified as Class B common stock, and all shares of redeemable convertible preferred stock then outstanding were converted into 59,491,640 shares of common stock on a one -to-one basis and then reclassified into Class B common stock. Convertible Senior Notes In February 2018, the Company issued $345.0 million aggregate principal amount of 0.25% convertible senior notes due February 15, 2023 in a private offering, including the initial purchasers’ exercise in full of their option to purchase additional notes (2023 Notes). The Company received aggregate proceeds of $345.0 million , before deducting costs of issuance of $10.0 million . See Note 8 for additional details. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates, judgments and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The Company bases its estimates on historical experience and on other assumptions that its management believes are reasonable under the circumstances. Actual results could vary from those estimates. The Company’s most significant estimates include the stand alone selling price (SSP) for each distinct performance obligation included in customer contracts with multiple performance obligations, the determination of the period of benefit for deferred commissions, the determination of the effective interest rate of the liability components of the 2023 Notes, the valuation of deferred income tax assets and contingencies and the valuation of acquired intangible assets.

Accounting Standards and Signif

Accounting Standards and Significant Accounting Policies	6 Months Ended
	Jul. 31, 2018
Accounting Policies [Abstract]
Accounting Standards and Significant Accounting Policies	Accounting Standards and Significant Accounting Policies Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). Topic 606 supersedes the revenue recognition requirements in Accounting Standards Codification (ASC) Topic 605, Revenue Recognition (Topic 605), and requires the recognition of revenue when promised goods or services are transferred to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. Topic 606 also includes Subtopic 340-40, Other Assets and Deferred Costs - Contracts with Customers, which requires the deferral of incremental costs of obtaining a contract with a customer. Collectively, the Company refers to Topic 606 and Subtopic 340-40 as "ASC 606." The Company adopted the requirements of ASC 606 as of February 1, 2018, utilizing the full retrospective method of transition. Adoption of ASC 606 resulted in changes to the Company’s accounting policies for revenue recognition and deferred commissions as detailed below. The Company applied ASC 606 using a practical expedient where the consideration allocated to the remaining performance obligations or an explanation of when the Company expects to recognize that amount as revenue for all reporting periods presented before the date of the initial application is not disclosed. The impact of adopting ASC 606 on fiscal 2018 and 2017 revenue is not material. The primary impact of adopting ASC 606 relates to the deferral of incremental commission costs of obtaining contracts. Under Topic 605, the Company deferred only direct and incremental commission costs to obtain a contract and amortized those costs on a straight-line basis over the term of the related contract, which was generally one to three years. Under ASC 606, the Company defers all incremental commission costs to obtain the contract. The Company amortizes these costs on a straight-line basis over a period of benefit, determined to be generally five years or the related contractual renewal term. The Company adjusted its condensed consolidated financial statements from amounts previously reported due to the adoption of ASC 606. Select condensed consolidated statement of operations line items, which reflect the adoption of ASC 606, are as follows (in thousands except per share data): Three Months Ended July 31, 2017 Six Months Ended July 31, 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted (unaudited) (unaudited) Revenue: Subscription $ 56,080 $ (763 ) $ 55,317 $ 104,437 $ (841 ) $ 103,596 Professional services and other 4,915 27 4,942 9,565 (577 ) 8,988 Total revenue 60,995 (736 ) 60,259 114,002 (1,418 ) 112,584 Gross profit 41,313 (736 ) 40,577 76,857 (1,418 ) 75,439 Operating expenses: Sales and marketing 39,597 (1,706 ) 37,891 76,777 (3,583 ) 73,194 Total operating expenses 68,468 (1,706 ) 66,762 132,646 (3,583 ) 129,063 Loss before income taxes (26,773 ) 970 (25,803 ) (55,426 ) 2,165 (53,261 ) Net loss (27,002 ) 970 (26,032 ) (55,903 ) 2,165 (53,738 ) Net loss per share, basic and diluted (0.29 ) 0.01 (0.28 ) (0.83 ) 0.03 (0.80 ) Select condensed consolidated balance sheet line items, which reflect the adoption of ASC 606, are as follows (in thousands): As of January 31, 2018 As Reported Adjustments As Adjusted (unaudited) Assets Current assets: Deferred commissions $ 16,481 $ 1,274 $ 17,755 Prepaid expenses and other current assets 16,973 808 17,781 Total current assets 315,416 2,082 317,498 Deferred commissions, noncurrent 10,971 29,784 40,755 Total assets 367,397 31,866 399,263 Liabilities and stockholders’ equity Current liabilities: Deferred revenue $ 162,633 $ (2,817 ) $ 159,816 Total current liabilities 190,760 (2,817 ) 187,943 Deferred revenue, noncurrent 6,034 (1,071 ) 4,963 Total liabilities 203,811 (3,888 ) 199,923 Accumulated deficit (402,468 ) 35,754 (366,714 ) Total stockholders’ equity 163,586 35,754 199,340 Total liabilities and stockholders’ equity 367,397 31,866 399,263 The adoption of ASC 606 had no impact on cash provided by or used in operating, financing, or investing activities in the Company’s condensed consolidated statement of cash flows. Additionally, the adoption of ASC 606 did not have a material impact on the provision for (benefit from) income taxes. The adoption adjustments impacted the deferred income taxes pertaining to the U.S. entity which are subject to a full valuation allowance. Significant Accounting Policies The Company’s significant accounting policies are discussed in “Note 2. Summary of Significant Accounting Policies” in Item 8. Financial Statements and Supplementary Data of its Form 10-K for the fiscal year ended January 31, 2018. Except for the accounting policies for revenue recognition and deferred commissions that were updated below as a result of adopting ASC 606, and the accounting policies for convertible senior notes, there have been no significant changes to these policies for the six months ended July 31, 2018 . Revenue Recognition The Company derives revenue from subscription fees (which include support fees) and professional services fees. The Company sells subscriptions to its platform through arrangements that are generally one to five years in length. The Company’s arrangements are generally noncancelable and nonrefundable. Furthermore, if a customer reduces the contracted usage or service level, the customer has no right of refund. The Company’s subscription arrangements do not provide customers with the right to take possession of the software supporting the platform and, as a result, are accounted for as service arrangements. This revenue recognition policy is consistent for sales generated directly with customers and sales generated indirectly through channel partners. The Company determines revenue recognition through the following steps: • 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, the Company satisfies a performance obligation Subscription Revenue Subscription revenue, which includes support, is recognized on a straight-line basis over the noncancelable contractual term of the arrangement, generally beginning on the date that the Company’s service is made available to the customer. Professional Services Revenue The Company’s professional services principally consist of customer-specific requests for application integrations, user interface enhancements and other customer-specific requests. Revenue for the Company’s professional services are recognized as services are performed in proportion with their pattern of transfer. Contracts with Multiple Performance Obligations Some of the Company’s contracts with customers contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative SSP basis. The Company determines SSP based on, if available, observable prices for those related services when sold separately. When observable prices are not available, the Company determines SSP based on overarching pricing objectives and strategies, taking into consideration market conditions and other factors, including customer size, volume purchased, market and industry conditions, product-specific factors and historical sales of the deliverables. Geographic Information Revenue by location is determined by the billing address of the customer. The following table sets forth revenue in dollars by geographic area (in thousands): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 As Adjusted (1) As Adjusted (1) United States $ 79,499 $ 50,972 $ 150,757 $ 95,943 International 15,087 9,287 27,450 16,641 Total $ 94,586 $ 60,259 $ 178,207 $ 112,584 _______________________________ (1) T he prior periods presented above have been adjusted to reflect the adoption of ASC 606 . Other than the United States, no individual country exceeded 10% of total revenue for the three and six months ended July 31, 2018 and 2017 . Accounts Receivable and Allowances Accounts receivable are recorded at the invoiced amount, net of allowances. These allowances are based on the Company’s assessment of the collectability of accounts by considering the age of each outstanding invoice and the collection history of each customer and an evaluation of potential risk of loss associated with delinquent accounts. Amounts deemed uncollectible are recorded to these allowances in the condensed consolidated balance sheets with an offsetting decrease in related deferred revenue or a charge in the condensed consolidated statement of operations. For the three and six months ended July 31, 2018 and 2017 , write-offs were not material. Deferred Commissions Sales commissions earned by the Company’s sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions for new revenue contracts, including incremental sales to existing customers, are deferred and then amortized on a straight-line basis over a period of benefit, which the Company has determined to be generally five years. The Company determined the period of benefit by taking into consideration its customer contracts, its technology and other factors. Sales commissions for renewal contracts (which are not considered commensurate with sales commissions for new revenue contracts and incremental sales to existing customers) are deferred and then amortized on a straight-line basis over the related period of benefit, which is generally the related contract renewal term. Amortization expense is included in sales and marketing expenses in the accompanying condensed consolidated statements of operations. Sales commissions capitalized as contract costs totaled $8.5 million and $5.3 million in the three months ended July 31, 2018 and 2017 , respectively, and $14.2 million and $9.5 million in the six months ended July 31, 2018 and 2017 , respectively. Amortization of contract costs was $5.0 million and $3.7 million for the three months ended July 31, 2018 and 2017 , respectively, and $9.6 million and $7.0 million for the six months ended July 31, 2018 and 2017 , respectively. There was no impairment loss in relation to the costs capitalized. Convertible Senior Notes The 2023 Notes are accounted for in accordance with FASB ASC Subtopic 470‑20, Debt with Conversion and Other Options. Pursuant to ASC Subtopic 470‑20, issuers of certain convertible debt instruments, such as the 2023 Notes, that have a net settlement feature and may be settled wholly or partially in cash upon conversion are required to separately account for the liability (debt) and equity (conversion option) components of the instrument. The carrying amount of the liability component of the instrument is computed by estimating the fair value of a similar liability without the conversion option. The amount of the equity component is then calculated by deducting the fair value of the liability component from the principal amount of the instrument. The difference between the principal amount and the liability component represents a debt discount that is amortized to interest expense over the respective term of the 2023 Notes using the effective interest rate method. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. In accounting for the issuance costs related to the 2023 Notes, the allocation amount of issuance costs incurred to liability and equity components was based on their relative values. Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02 (Topic 842). Topic 842 amends a number of aspects of lease accounting, including requiring lessees to recognize leases with a term greater than one year as a right-of-use asset and corresponding liability, measured at the present value of the lease payments. In July 2018, the FASB issued supplemental adoption guidance and clarification to Topic 842 within ASU 2018-10 “Codification Improvements to Topic 842, Leases” and ASU 2018-11 “Leases (Topic 842): Targeted Improvements.” The new guidance aims to increase transparency and comparability among organizations by requiring lessees to recognize lease assets and lease liabilities on the balance sheet and requiring disclosure of key information about leasing arrangements. A modified retrospective application is required with an option to not restate comparative periods in the period of adoption. This guidance is effective for the Company on February 1, 2019 with early adoption permitted. The Company is currently evaluating the impact of the adoption of this standard on its consolidated financial statements, which will consist primarily of a balance sheet gross up of its operating leases to show equal and offsetting right-of-use assets and lease liabilities. In February 2018, the FASB issued ASU No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (ASU 2018-02). Under existing U.S. GAAP, the effects of changes in tax rates and laws on deferred tax balances are recorded as a component of income tax expense in the period in which the law was enacted. When deferred tax balances related to items originally recorded in accumulated other comprehensive income (loss) are adjusted, certain tax effects become stranded in accumulated other comprehensive income. The amendments in ASU 2018-02 allow a reclassification from accumulated other comprehensive income (loss) to retained earnings (accumulated deficit) for stranded income tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act). The amendments in this ASU also require certain disclosures about stranded income tax effects. The guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption in any period is permitted. The Company’s provisional adjustments recorded in fiscal year 2018 to account for the impact of the Tax Act did not result in stranded tax effects. The Company does not anticipate that the adoption of this standard will have a material impact on its condensed consolidated financial statements.

Business Combinations

Business Combinations	6 Months Ended
	Jul. 31, 2018
Business Combinations [Abstract]
Business Combinations	Business Combinations Stormpath On February 17, 2017, the Company acquired the rights to hire certain employees and a non-exclusive intellectual property license from Stormpath, Inc. (Stormpath), a privately-held technology company which had built a user management and authentication service for software development teams. The transaction was accounted for as a business combination. The total consideration of $3.7 million , consisting of 200,000 shares of common stock valued at $2.2 million , at the time of the transaction, issued to Stormpath and replacement awards of $1.5 million issued to the hired employees, was recognized as goodwill. In addition, the Company issued to Stormpath an incremental 800,000 shares of restricted common stock valued at $8.6 million , at the time of the transaction, which is being recognized as post-combination stock-based compensation expense . See Note 10 for further details. ScaleFT On July 13, 2018, the Company acquired all issued and outstanding capital stock of ScaleFT, Inc. (ScaleFT), a “zero trust” security company which provides access solutions for the modern workforce. The preliminary acquisition date cash consideration transferred for ScaleFT was $15.6 million , net of $0.6 million in cash received. The Company recorded $4.6 million for developed technology intangible assets with estimated useful life of three years and $11.8 million of goodwill which is primarily attributed to the assembled workforce as well as the integration of ScaleFT’s technology and the Company’s technology. The Company incurred $1.1 million of acquisition related costs. The business combination did not have a material impact on the condensed consolidated financial statements and therefore historical and proforma disclosures have not be presented.

Cash Equivalents and Short-Term

Cash Equivalents and Short-Term Investments	6 Months Ended
	Jul. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Cash Equivalents and Short-Term Investments	Cash Equivalents and Short-Term Investments The amortized cost, unrealized gain (loss) and estimated fair value of the Company’s cash equivalents and short-term investments as of July 31, 2018 and January 31, 2018 were as follows (in thousands): As of July 31, 2018 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value (unaudited) Cash equivalents: Money market funds $ 155,347 $ — $ — $ 155,347 Commercial paper 12,237 — — 12,237 Total cash equivalents $ 167,584 $ — $ — $ 167,584 Short-term investments: Commercial paper $ 56,191 $ — $ — $ 56,191 U.S. treasury securities 248,081 — (217 ) 247,864 Corporate debt securities 39,352 6 (39 ) 39,319 Total short-term investments 343,624 6 (256 ) 343,374 Total $ 511,208 $ 6 $ (256 ) $ 510,958 As of January 31, 2018 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Cash equivalents: Money market funds $ 90,770 $ — $ — $ 90,770 Total cash equivalents $ 90,770 $ — $ — $ 90,770 Short-term investments: Commercial paper $ 15,946 $ — $ — $ 15,946 U.S. treasury securities 61,896 — (158 ) 61,738 Corporate debt securities 24,125 — (44 ) 24,081 Total short-term investments 101,967 — (202 ) 101,765 Total $ 192,737 $ — $ (202 ) $ 192,535 All short-term investments were designated as available-for-sale securities as of July 31, 2018 and January 31, 2018 . The following tables present the contractual maturities of the Company’s short-term investments as of July 31, 2018 and January 31, 2018 (in thousands): As of July 31, 2018 As of January 31, 2018 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value (unaudited) Due within one year $ 328,694 $ 328,460 $ 93,421 $ 93,237 Due between one to five years 14,930 14,914 8,546 8,528 $ 343,624 $ 343,374 $ 101,967 $ 101,765 The Company had 53 and 23 short-term investments in unrealized loss positions as of July 31, 2018 and January 31, 2018 , respectively. There were no material gross unrealized gains or losses from available-for-sale securities and no realized gains or losses from available-for-sale securities that were reclassified out of accumulated other comprehensive income for the three and six months ended July 31, 2018 or 2017 . For available-for-sale debt securities that have unrealized losses, the Company evaluates whether (i) the Company has the intention to sell any of these investments and (ii) it is not more likely than not that the Company will be required to sell any of these available-for-sale debt securities before recovery of the entire amortized cost basis. Based on this evaluation, the Company determined that there were no other-than-temporary impairments associated with short-term investments as of July 31, 2018 and January 31, 2018 .

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jul. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company measures its financial assets at fair value each reporting period using a fair value hierarchy that prioritizes the use of observable inputs and minimizes 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 as follows: Level 1-Valuations based on observable inputs that reflect quoted prices for identical assets or liabilities in active markets. Level 2-Valuations based on inputs that are directly or indirectly observable in the marketplace. Level 3-Valuations based on unobservable inputs that are supported by little or no market activity. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis using the above input categories (in thousands): As of July 31, 2018 Level 1 Level 2 Level 3 Total (unaudited) Assets: Cash equivalents: Money market funds $ 155,347 $ — $ — $ 155,347 Commercial paper — 12,237 — 12,237 Total cash equivalents $ 155,347 $ 12,237 $ — $ 167,584 Short-term investments: Commercial paper $ — $ 56,191 $ — $ 56,191 U.S. treasury securities — 247,864 — 247,864 Corporate debt securities — 39,319 — 39,319 Total short-term investments — 343,374 — 343,374 Total cash equivalents and short-term investments $ 155,347 $ 355,611 $ — $ 510,958 As of January 31, 2018 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 90,770 $ — $ — $ 90,770 Total cash equivalents $ 90,770 $ — $ — $ 90,770 Short-term investments: Commercial paper $ — $ 15,946 $ — $ 15,946 U.S. treasury securities — 61,738 — 61,738 Corporate debt securities — 24,081 — 24,081 Total short-term investments — 101,765 — 101,765 Total cash equivalents and short-term investments $ 90,770 $ 101,765 $ — $ 192,535 The Company had no transfers between levels of the fair value hierarchy of its assets measured at fair value. The carrying amounts of certain financial instruments, including cash held in banks, accounts receivable and accounts payable approximate fair value due to their short-term maturities and are excluded from the fair value table above. Fair Value Measurements of Other Financial Instruments The following table presents the carrying amounts and estimated fair values of our financial instruments that are not recorded at fair value on the condensed consolidated balance sheets (in thousands): As of July 31, 2018 Net Carrying Amount Before Unamortized Debt Issuance Costs Estimated Fair Value (unaudited) Convertible senior notes $ 270,972 $ 421,800 The difference between the principal amount of the 2023 Notes, $345.0 million , and the net carrying amount before unamortized debt issuance costs represents the unamortized debt discount (See Note 8 for additional details). The estimated fair value of the 2023 Notes, which the Company has classified as Level 2 financial instruments, was determined based on the quoted bid price of the convertible senior notes in an over-the-counter market on the last trading day of the reporting period. As of July 31, 2018 , the difference between the net carrying amount of the 2023 Notes and estimated fair value represents the equity conversion value premium the market assigned to the 2023 Notes. Based on the closing price of our common stock of $49.65 on July 31, 2018 , the if-converted value of the 2023 Notes exceeded the principal amount of $345.0 million .

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, net	6 Months Ended
	Jul. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, net	Goodwill and Intangible Assets, net Goodwill As of July 31, 2018 and January 31, 2018 , goodwill was $18.1 million and $6.3 million , respectively. During the three months ended July 31, 2018 , the Company recorded $11.8 million of goodwill in connection with the ScaleFT acquisition that was completed in July 2018. See Note 3 for further details. No goodwill impairments were recorded during the three and six months ended July 31, 2018 and 2017 . Intangible Assets, net Intangible assets consisted of the following (in thousands): As of July 31, 2018 Gross Accumulated Amortization Net (unaudited) Capitalized internal-use software costs $ 18,467 $ (7,441 ) $ 11,026 Purchased developed technology 5,170 (570 ) 4,600 Software licenses 1,023 (643 ) 380 $ 24,660 $ (8,654 ) $ 16,006 As of January 31, 2018 Gross Accumulated Amortization Net Capitalized internal-use software costs $ 16,434 $ (5,172 ) $ 11,262 Software licenses 1,057 (558 ) 499 Purchased developed technology 570 (570 ) — $ 18,061 $ (6,300 ) $ 11,761 The Company capitalized $0.8 million and $1.9 million of internal-use software costs in the three months ended July 31, 2018 and 2017 , respectively, and $2.0 million and $3.3 million of internal-use software costs in the six months ended July 31, 2018 and 2017 , respectively. Included in the total amount capitalized is stock-based compensation expense of $0.1 million and $0.4 million for the three months ended July 31, 2018 and 2017 , respectively, and $0.3 million and $0.6 million for the six months ended July 31, 2018 and 2017 , respectively. In addition, during the three months ended July 31, 2018 , the Company acquired $4.6 million of purchased developed technology from the ScaleFT acquisition. See Note 3 for further details. Intangible amortization expense was $1.2 million and $0.7 million for the three months ended July 31, 2018 and 2017 , respectively, and $2.4 million and $1.4 million for the six months ended July 31, 2018 and 2017 , respectively.

Deferred Revenue and Performanc

Deferred Revenue and Performance Obligations	6 Months Ended
	Jul. 31, 2018
Revenue from Contract with Customer [Abstract]
Deferred Revenue and Performance Obligations	Deferred Revenue and Performance Obligations Deferred Revenue Deferred revenue, which is a contract liability, consists primarily of payments received in advance of revenue recognition under the Company’s contracts with customers and is recognized as the revenue recognition criteria are met. Subscription revenue recognized during the three months ended July 31, 2018 and 2017 that was included in the deferred revenue balances at the beginning of the respective periods was $73.1 million and $46.7 million , respectively, and $114.3 million and $73.3 million for the six months ended July 31, 2018 and 2017 , respectively. Professional services and other revenue recognized in the three and six months ended July 31, 2018 and 2017 from deferred revenue balances at the beginning of the respective periods was not material. Transaction Price Allocated to the Remaining Performance Obligations Transaction price allocated to the remaining performance obligations represents contracted revenue that has not yet been recognized, which includes deferred revenue for subscription contracts that have been invoiced and will be recognized as revenue in future periods. As of July 31, 2018 , total remaining noncancelable performance obligations under the Company’s subscription contracts with customers was approximately $543.9 million , and the Company expects to recognize revenue on approximately 56% of these remaining performance obligations over the next 12 months, with the balance to be recognized thereafter. Revenue from remaining performance obligations for professional services and other contracts as of July 31, 2018 was not material. Unbilled Receivables The Company receives payments from customers based on billing schedules as established in its contracts. Unbilled receivables, which are contract assets, relate to the Company’s rights to consideration for performance obligations satisfied but not billed at the reporting date on contracts. As of July 31, 2018 and January 31, 2018 , unbilled receivables were $0.8 million , which are included in prepaid expenses and other current assets in the condensed consolidated balance sheets. Unbilled receivables are transferred to accounts receivable when the rights become unconditional.

Debt and Financing Arrangements

Debt and Financing Arrangements	6 Months Ended
	Jul. 31, 2018
Debt Disclosure [Abstract]
Debt and Financing Arrangements	Debt and Financing Arrangements Convertible Senior Notes The 2023 Notes are senior, unsecured obligations of the Company, and bear interest at a fixed rate of 0.25% per year. Interest is payable in cash semi-annually in arrears on February 15 and August 15 of each year, beginning on August 15, 2018. The 2023 Notes mature on February 15, 2023 unless earlier repurchased or converted. The Company may not redeem the 2023 Notes prior to maturity. The total net proceeds from the 2023 Notes, after deducting initial purchasers’ discounts and debt issuance costs, was approximately $335.0 million . The terms of the 2023 Notes are governed by an Indenture by and between the Company and Wilmington Trust, National Association, as Trustee (the Indenture). Upon conversion, the 2023 Notes may be settled in cash, shares of Class A common stock or a combination of cash and shares of Class A common stock, at the Company’s election. It is the Company’s current intent to settle the principal amount of the 2023 Notes with cash. The 2023 Notes are convertible at an initial conversion rate of 20.6795 shares of Class A common stock per $1,000 principal amount of 2023 Notes, which is equal to an initial conversion price of approximately $48.36 per share of Class A common stock, subject to adjustment under certain circumstances in accordance with the terms of the Indenture. Prior to the close of business on the business day immediately preceding October 15, 2022, holders of the 2023 Notes may convert all or a portion of their 2023 Notes only in multiples of $1,000 principal amount, under the following circumstances: • during any fiscal quarter commencing after the fiscal quarter ending on April 30, 2018 (and only during such fiscal quarter), if the last reported sale price of Class A common stock for at least 20 trading days (whether or not consecutive) during the 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 of the 2023 Notes on each applicable trading day; • during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of the 2023 Notes for each trading day of that five consecutive trading day period was less than 98% of the product of the last reported sale price of Class A common stock and the conversion rate on such trading day; or • upon the occurrence of specified corporate events, as described in the Indenture. 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 2023 Notes regardless of the foregoing circumstances. During the three and six months ended July 31, 2018 , the conditions allowing holders of the 2023 Notes to convert were not met. Holders of the 2023 Notes who convert their 2023 Notes in connection with certain corporate events that constitute a make-whole fundamental change (as defined in the Indenture) are, under certain circumstances, entitled to an increase in the conversion rate. Additionally, in the event of a corporate event that constitutes a fundamental change (as defined in the Indenture), holders of the 2023 Notes may require the Company to repurchase all or a portion of their 2023 Notes at a price equal to 100% of the principal amount of the 2023 Notes being repurchased, plus any accrued and unpaid interest. In accounting for the issuance of the 2023 Notes, the Company separated the 2023 Notes into liability and equity components. The carrying amounts of the liability components were calculated by measuring the fair value of similar liabilities that do not have associated convertible features. The carrying amount of the equity components representing the conversion option were determined by deducting the fair value of the liability component from the par value of the 2023 Notes. The Company bifurcated the conversion option of the 2023 Notes from the debt instrument, classified the conversion option in equity and will accrete the resulting debt discount as interest expense over the contractual term of the 2023 Notes using the effective interest rate method. The equity component is not remeasured as long as they continue to meet the conditions for equity classification. The effective interest rate of the liability component of the 2023 Notes is 5.68% . This interest rate was based on the interest rates of similar liabilities held by other companies with similar credit risk ratings at the time of issuance that did not have associated convertible features. The following table sets forth total interest expense recognized related to the 2023 Notes (in thousands): Three Months Ended July 31, 2018 Six Months Ended July 31, 2018 (unaudited) Contractual interest expense $ 216 $ 362 Amortization of debt issuance costs 288 478 Amortization of debt discount 3,554 5,935 Total $ 4,058 $ 6,775 Total issuance costs of $10.0 million related to the 2023 Notes were allocated between liability and equity in the same proportion as the allocation of the total proceeds to the liability and equity components. Issuance costs attributable to the liability component are being amortized to interest expense over the respective term of the 2023 Notes using the effective interest rate method. The issuance costs attributable to the equity component were netted against the respective equity component in Additional paid-in capital. The Company recorded liability issuance costs of $7.7 million and equity issuance costs of $2.3 million . The 2023 Notes, net consisted of the following (in thousands): As of July 31, 2018 (unaudited) Liability component: Principal $ 345,000 Less: unamortized debt issuance costs and debt discount (81,238 ) Net carrying amount $ 263,762 At Issuance (unaudited) Equity component: 2023 Notes $ 79,962 Less: issuance costs (2,320 ) Carrying amount of the equity component (1) $ 77,642 (1) Included in the condensed consolidated balance sheets within Additional paid-in capital. Note Hedges In connection with the pricing of the 2023 Notes, the Company entered into convertible note hedge transactions with respect to its Class A common stock (the Note Hedges). The Note Hedges are purchased call options that give the Company the option to purchase, subject to anti-dilution adjustments substantially identical to those in the 2023 Notes, approximately 7.1 million shares of its Class A common stock for $48.36 per share (subject to adjustment), corresponding to the approximate initial conversion price of the 2023 Notes, exercisable upon conversion of the 2023 Notes. The Note Hedges will expire in 2023, if not exercised earlier. The Note Hedges are intended to offset potential dilution to the Company’s Class A common stock and/or offset the potential cash payments that the Company could be required to make in excess of the principal amount upon any conversion of the 2023 Notes under certain circumstances. The Note Hedges are separate transactions and are not part of the terms of the 2023 Notes. The Company paid an aggregate amount of $80.0 million for the Note Hedges. The amount paid for the Note Hedges was recorded as a reduction to Additional paid-in capital in the condensed consolidated balance sheets. See Note 11 for the tax impacts of the 2023 Notes and Note Hedges. Warrants In connection with the issuance of the 2023 Notes, the Company also entered into separate warrant transactions pursuant to which it sold net-share-settled (or, at the Company’s election subject to certain conditions, cash-settled) warrants (the Warrants) to acquire, subject to anti-dilution adjustments, up to approximately 7.1 million shares over 80 scheduled trading days beginning in May 2023 of the Company’s Class A common stock at an initial exercise price of $68.06 per share (subject to adjustment). If the Warrants are not exercised on their exercise dates, they will expire. If the market value per share of the Company’s Class A common stock exceeds the applicable exercise price of the Warrants, the Warrants could have a dilutive effect on the Company’s Class A common stock unless, subject to the terms of the Warrants, the Company elects to cash settle the Warrants. The Warrants are separate transactions and are not part of the terms of the 2023 Notes or the Note Hedges. The Company received aggregate proceeds of $52.4 million from the sale of the Warrants in connection with the 2023 Notes. The proceeds from the sale of the Warrants was recorded as an increase to Additional paid-in capital in the condensed consolidated balance sheets. Loan and Security Agreement The Company has available a line of credit (Revolving Line) with Silicon Valley Bank (SVB) in the amount of $40.0 million , with a maturity date of November 21, 2018. The available amount, not to exceed $40.0 million , is based on certain revenue metrics and is reduced by letters of credit totaling $4.2 million as of July 31, 2018 established in connection with facility lease agreements. As of July 31, 2018 , $35.8 million was available under the Revolving Line. Proceeds from loans made under the Revolving Line may be borrowed, repaid and reborrowed until November 21, 2018. Repayment of any outstanding proceeds are payable on November 21, 2018, but may be prepaid without penalty. Borrowings under the Revolving Line bear interest at an annual rate based on the one-year Prime rate plus a spread of 0.75% . Interest is payable quarterly. The Company is required to pay a quarterly facility fee to SVB of 0.15% per annum on the average undrawn portion available under the facility plus balances of outstanding letters of credits. Additionally, the Company is required to pay an upfront, one-time, commitment fee of $0.1 million and annual anniversary fees of $0.1 million on the amendment’s first and second anniversary dates. As of July 31, 2018 and January 31, 2018 , no amounts had been drawn under the Revolving Line and the Company was in compliance with all covenants pursuant to the loan and security agreement.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jul. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases The Company leases office space under noncancelable operating leases for its San Francisco, California headquarters, as well as its offices in various cities in the United States, United Kingdom, Australia and Canada. These office leases expire on various dates through October 2028. Deferred rent was $30.5 million and $5.5 million as of July 31, 2018 and January 31, 2018 , respectively, which is included in accrued expenses and other current liabilities and other liabilities, noncurrent in the condensed consolidated balance sheets. Rent expense was $5.8 million and $2.5 million for the three months ended July 31, 2018 and 2017 , respectively and $9.2 million and $4.7 million for the six months ended July 31, 2018 and 2017 , respectively. In conjunction with the execution of leases, letters of credit in the aggregate amount of $12.5 million and $12.2 million were issued and outstanding as of July 31, 2018 and January 31, 2018 , respectively. No draws have been made under such letters of credit. The Company secured its new corporate headquarters lease in San Francisco with an $8.0 million letter of credit, which is designated as restricted cash and included in other assets on its condensed consolidated balance sheet as of July 31, 2018 . In June 2018, the Company signed an agreement to sublease the premises at 634 2nd Street, San Francisco, California (2nd Street Sublease), which, together with the premises at 301 Brannan Street, San Francisco, California, comprise the Company’s current headquarters. The term of the 2nd Street Sublease agreement commences on January 31, 2019. The 2nd Street Sublease and the master lease both expire in September 2024. The Company’s future income under the terms of the 2nd Street Sublease agreement will be approximately equal to the amount required to be paid by the Company to its landlord under the terms of the master lease. The Company and the sub-lessee executed a standby letter of credit amounting to $3.0 million to be held by the Company to secure the 2nd Street Sublease in the event of uncured default by the sub-lessee. Pursuant to a termination agreement pertaining to the Company’s lease of the premises at 301 Brannan Street, San Francisco, California, the non-cancellable lease term for those premises now expires in January 2019 instead of July 2019. Legal Matters From time to time in the normal course of business, the Company may be subject to various legal matters such as threatened or pending claims or proceedings. There were no such material matters as of July 31, 2018 .

Employee Incentive Plans

Employee Incentive Plans	6 Months Ended
	Jul. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Employee Incentive Plans	Employee Incentive Plans The Company’s equity incentive plans provide for granting stock options, restricted stock units (RSUs) and restricted stock awards to employees, consultants, officers and directors. In addition, the Company offers an Employee Stock Purchase Plan (ESPP) to eligible employees. Stock-based compensation expense was recorded in the following cost and expense categories in the Company’s condensed consolidated statements of operations (in thousands): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 (unaudited) Cost of revenue Subscription $ 1,901 $ 1,056 $ 3,430 $ 1,742 Professional services and other 1,083 738 1,972 1,207 Research and development 5,272 4,438 9,485 7,739 Sales and marketing 5,471 3,021 9,624 5,396 General and administrative 4,495 2,725 7,846 4,800 Total $ 18,222 $ 11,978 $ 32,357 $ 20,884 Stock-based compensation expense recorded to research and development in the condensed consolidated statements of operations excludes amounts that were capitalized related to internal-use software for the three and six months ended July 31, 2018 and 2017 . See Note 6 for further details. Equity Incentive Plans The Company has two equity incentive plans: the 2009 Stock Plan (2009 Plan) and the 2017 Equity Incentive Plan (2017 Plan). Upon the completion of the Company’s IPO in April 2017, the Company ceased granting equity under the 2009 Plan, and all shares that remained available for future issuance under the 2009 Plan at that time were transferred to the 2017 Plan. As of July 31, 2018 , options granted under the 2009 Plan to purchase 20,133,894 shares of Class B common stock remain outstanding and options granted under the 2017 Plan to purchase 764,596 shares of Class A common stock remain outstanding. Shares of common stock reserved for future issuance are as follows: As of July 31, 2018 (unaudited) Stock options and unvested RSUs outstanding 25,789,276 Available for future stock option and RSU grants 12,464,154 Available for ESPP 3,035,697 41,289,127 Stock Options A summary of the Company’s stock option activity and related information is as follows: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding as of January 31, 2018 24,917,045 $ 7.37 7.6 $ 550,173 Granted 684,500 39.21 Exercised (4,025,395 ) 5.23 Canceled (677,660 ) 8.41 Outstanding as of July 31, 2018 (unaudited) 20,898,490 $ 8.79 7.4 $ 853,892 As of July 31, 2018 Vested and exercisable (unaudited) 9,797,292 $ 6.35 6.8 $ 424,203 No stock options were granted in the three months ended July 31, 2018 and 2017 . The weighted-average grant-date fair value of options granted was $17.21 and $5.36 during the six months ended July 31, 2018 and 2017 , respectively. The total grant-date fair value of stock options vested was $7.8 million and $8.4 million during the three months ended July 31, 2018 and 2017 , respectively, and $13.5 million and $13.0 million for the six months ended July 31, 2018 and 2017 , respectively. The intrinsic value of the options exercised, which represents the difference between the fair market value of the Company’s common stock on the date of exercise and the exercise price of each option, was $73.2 million and $5.3 million for the three months ended July 31, 2018 and 2017 , respectively, and $155.1 million and $19.3 million for the six months ended July 31, 2018 and 2017 , respectively. As of July 31, 2018 , there was a total of $50.9 million of unrecognized stock-based compensation expense, which is expected to be recognized over a weighted-average period of 2.3 years. The Company used the Black-Scholes option pricing model to estimate the fair value of stock options granted with the following assumptions: Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 (unaudited) Expected volatility — — 40% 40% - 41% Expected term (in years) — — 6.25 6.0 - 6.4 Risk-free interest rate — — 2.70% 2.06% - 2.21% Expected dividend yield — — — — Restricted Stock Units A summary of the Company’s RSU activity and related information is as follows: Number of Weighted- Outstanding as of January 31, 2018 2,862,929 $ 24.38 Granted 2,752,588 50.67 Vested (542,969 ) 22.71 Forfeited (181,762 ) 29.39 Outstanding as of July 31, 2018 (unaudited) 4,890,786 $ 39.17 As of July 31, 2018 , there was $180.2 million of unrecognized stock-based compensation expense related to unvested RSUs, which is expected to be recognized over a weighted-average period of 3.4 years based on vesting under the award service conditions. Equity Awards Issued in Connection with Business Combination In connection with the Stormpath transaction in February 2017, the Company issued 800,000 shares of restricted common stock to Stormpath with an aggregate fair value of $8.6 million at the time of the transaction to be recognized as post combination stock-based compensation. The restricted common stock vests ratably on the first and second anniversaries of the transaction date upon achievement of the respective performance conditions , of which 400,000 shares vested during the six months ended July 31, 2018. As of July 31, 2018 , there was $1.2 million of unrecognized compensation expense related to restricted common stock which is expected to be recognized over the remaining weighted average life of 0.6 years. The Company separately entered into retention arrangements with certain employees of Stormpath and issued 598,500 restricted stock awards under the 2009 Plan with an aggregate fair value of $6.6 million at the time of the transaction with performance conditions. Additionally, the Company granted 518,900 service-based stock options under the 2009 Plan to certain Stormpath employees with an aggregate fair value of $2.5 million to vest ratably over the requisite four -year service period. Of the $9.1 million total aggregate fair value of the awards, $1.5 million was related to pre-combination service and was recognized as goodwill and a reduction to the post-combination compensation expense. The post-combination expenses for the restricted stock awards and stock options are $5.5 million and $2.1 million , respectively. The expense related to the restricted stock awards is being recognized over two or three years based on an accelerated attribution method. The expense for the stock options is being recognized ratably over the requisite service period. During the six months ended July 31, 2018 , 210,850 shares of restricted stock awards vested . As of July 31, 2018 , there was $1.4 million of unrecognized compensation expense related to unvested restricted stock awards, which is expected to be recognized over the remaining weighted average life of 1.0 year. As of July 31, 2018 , there was $1.4 million of unrecognized compensation cost related to unvested stock options, which is expected to be recognized over the remaining weighted average life of 1.9 years. The related stock options expense and activity are included within the Stock Options section above. Employee Stock Purchase Plan Except for the initial offering period, the ESPP provides for 12 -month offering periods beginning June 21 and December 21 of each year, and each offering period consists of up to two six -month purchase periods. The initial offering period began April 7, 2017 and ended on June 20, 2018. The Company estimated the fair value of ESPP purchase rights using a Black-Scholes option pricing model with the following assumptions: Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 (unaudited) Expected volatility 39% - 40% 32% - 34% 39% - 40% 32% - 37% Expected term (in years) 0.5 - 1.0 0.5 - 1.0 0.5 - 1.0 0.5 - 1.2 Risk-free interest rate 2.12% - 2.34% 1.12% - 1.22% 2.12% - 2.34% 0.95% - 1.22% Expected dividend yield — — — — During the three and six months ended July 31, 2018 , the Company’s employees purchased 434,640 shares of its Class A common stock under the ESPP. The shares were purchased at a weighted-average purchase price of $15.31 with proceeds of $6.7 million . As of July 31, 2018 , there was $5.3 million of unrecognized stock-based compensation expense related to ESPP that is expected to be recognized over an average vesting period of 0.7 years. Awards Issued as Charitable Contributions During the three and six months ended July 31, 2018 , the Company granted 20,000 shares of Class A common stock as charitable contributions and recognized $1.0 million as general and administrative expense in the condensed consolidated statement of operations. During the three and six months ended July 31, 2017 , the Company did not grant any common stock as a charitable contribution.

Income Taxes

Income Taxes	6 Months Ended
	Jul. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three and six months ended July 31, 2018 , the Company recorded a tax benefit of $1.0 million and $1.2 million , respectively, on pretax losses of $40.2 million and $66.4 million , respectively. The effective tax rate for the three and six months ended July 31, 2018 was 2.5% and 1.8% , respectively. The effective tax rate differs from the statutory rate primarily as a result of not recognizing deferred tax assets for U.S. losses due to a full valuation allowance against U.S. deferred tax assets, release of the valuation allowance in the United States in connection with the ScaleFT acquisition and excess tax benefits from stock-based compensation in the United Kingdom. The tax benefit was partially offset by income tax expense in profitable foreign jurisdictions and U.S. state taxes. For the three and six months ended July 31, 2017 , the Company recorded tax provisions of $0.2 million and $0.5 million , respectively, on pretax losses of $25.8 million and $53.3 million , respectively. The effective tax rate for both the three and six months ended July 31, 2017 was (0.9)% . The effective tax rate differs from the statutory rate primarily as a result of not recognizing a deferred tax asset for U.S. losses due to having a full valuation allowance against U.S. deferred tax assets. The difference between the book and tax bases of the 2023 Notes, Note Hedges and debt issuance costs resulted in deductible temporary differences and corresponding deferred tax assets of $0.6 million as of July 31, 2018, which are subject to a full valuation allowance. On December 22, 2017, the Tax Act was signed into law making significant changes to the Internal Revenue Code. Changes include, but are not limited to, a corporate tax rate decrease to 21% effective for tax years beginning after December 31, 2017, and changes to how the United States imposes income tax on multinational corporations. In December 2017, the SEC staff issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), which allows the Company to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. The Company recorded a provisional amount of $61.0 million as of January 31, 2018 related to the remeasurement of certain deferred tax balances before valuation allowance. For the six months ended July 31, 2018 , the Company has not made a material adjustment to the provisional amount. The Company will continue to analyze and refine the calculations to the measurement of these balances. The Company expects to complete its analysis within the measurement period in accordance with SAB 118. The United Kingdom tax authority completed its examination of fiscal year 2016 income tax returns for the Company’s UK subsidiary during the three months ended April 30, 2018 . As a result, the Company’s UK subsidiary is no longer subject to examination for fiscal years prior to 2017.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jul. 31, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 Class A Class B Class A Class B Class A Class B Class A Class B (unaudited) Numerator: Net loss (1) $ (33,862 ) $ (5,345 ) $ (4,075 ) $ (21,957 ) $ (53,242 ) $ (11,927 ) $ (7,254 ) $ (46,484 ) Denominator: Weighted-average shares outstanding - basic and diluted 92,156 14,546 14,650 78,926 86,172 19,303 9,061 58,064 Net loss per share attributable to common stockholders, basic and diluted $ (0.37 ) $ (0.37 ) $ (0.28 ) $ (0.28 ) $ (0.62 ) $ (0.62 ) $ (0.80 ) $ (0.80 ) (1) Net loss for the three and six months ended July 31, 2017 has been adjusted. See Note 2 for a summary of adjustments. As the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows (in thousands): As of July 31, 2018 2017 (unaudited) Unvested restricted common stock issued and outstanding 400 800 Stock options issued and outstanding 20,898 33,360 Unvested RSUs issued and outstanding 4,891 2,210 Unvested restricted stock awards issued and outstanding 388 599 Shares related to convertible senior notes 7,134 — Shares committed under the ESPP 360 1,082 Unvested shares subject to repurchase 96 324 34,167 38,375 The Company expects to settle the principal amount of the 2023 Notes in cash, and therefore, the Company uses the treasury stock method for calculating any potential dilutive effect of the conversion option on diluted net income per share, if applicable. The conversion option will have a dilutive impact on net income per share of common stock when the average market price per share of the Company’s Class A common stock for a given period exceeds the conversion price of the 2023 Notes of $48.36 per share. During the three months ended July 31, 2018 , the weighted average price per share of the Company’s Class A common stock exceeded the conversion price of the 2023 Notes; however, since the Company is in a net loss position there was no dilutive effect during any period presented.

Accounting Standards and Sign19

Accounting Standards and Significant Accounting Policies (Policies)	6 Months Ended
	Jul. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements, which include the accounts of the Company and its wholly owned subsidiaries, have been prepared in conformity with U.S. generally accepted accounting principles (GAAP).
Principles of Consolidation	All intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated balance sheet as of January 31, 2018 , included herein, was derived from the audited financial statements as of that date. The unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the balance sheet, statements of operations, statements of comprehensive loss and the statements of cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full fiscal year ending January 31, 2019 or any future period.
Fiscal Period	The Company’s fiscal year ends on January 31. References to fiscal 2019 , for example, refer to the fiscal year ending January 31, 2019 .
Use of Estimates	The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates, judgments and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The Company bases its estimates on historical experience and on other assumptions that its management believes are reasonable under the circumstances. Actual results could vary from those estimates. The Company’s most significant estimates include the stand alone selling price (SSP) for each distinct performance obligation included in customer contracts with multiple performance obligations, the determination of the period of benefit for deferred commissions, the determination of the effective interest rate of the liability components of the 2023 Notes, the valuation of deferred income tax assets and contingencies and the valuation of acquired intangible assets.
Revenue Recognition	The Company derives revenue from subscription fees (which include support fees) and professional services fees. The Company sells subscriptions to its platform through arrangements that are generally one to five years in length. The Company’s arrangements are generally noncancelable and nonrefundable. Furthermore, if a customer reduces the contracted usage or service level, the customer has no right of refund. The Company’s subscription arrangements do not provide customers with the right to take possession of the software supporting the platform and, as a result, are accounted for as service arrangements. This revenue recognition policy is consistent for sales generated directly with customers and sales generated indirectly through channel partners. The Company determines revenue recognition through the following steps: • 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, the Company satisfies a performance obligation Subscription Revenue Subscription revenue, which includes support, is recognized on a straight-line basis over the noncancelable contractual term of the arrangement, generally beginning on the date that the Company’s service is made available to the customer. Professional Services Revenue The Company’s professional services principally consist of customer-specific requests for application integrations, user interface enhancements and other customer-specific requests. Revenue for the Company’s professional services are recognized as services are performed in proportion with their pattern of transfer. Contracts with Multiple Performance Obligations Some of the Company’s contracts with customers contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative SSP basis. The Company determines SSP based on, if available, observable prices for those related services when sold separately. When observable prices are not available, the Company determines SSP based on overarching pricing objectives and strategies, taking into consideration market conditions and other factors, including customer size, volume purchased, market and industry conditions, product-specific factors and historical sales of the deliverables.
Accounts Receivable and Allowances	Accounts receivable are recorded at the invoiced amount, net of allowances. These allowances are based on the Company’s assessment of the collectability of accounts by considering the age of each outstanding invoice and the collection history of each customer and an evaluation of potential risk of loss associated with delinquent accounts. Amounts deemed uncollectible are recorded to these allowances in the condensed consolidated balance sheets with an offsetting decrease in related deferred revenue or a charge in the condensed consolidated statement of operations.
Deferred Commissions	Sales commissions earned by the Company’s sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions for new revenue contracts, including incremental sales to existing customers, are deferred and then amortized on a straight-line basis over a period of benefit, which the Company has determined to be generally five years. The Company determined the period of benefit by taking into consideration its customer contracts, its technology and other factors. Sales commissions for renewal contracts (which are not considered commensurate with sales commissions for new revenue contracts and incremental sales to existing customers) are deferred and then amortized on a straight-line basis over the related period of benefit, which is generally the related contract renewal term. Amortization expense is included in sales and marketing expenses in the accompanying condensed consolidated statements of operations.
Convertible Senior Notes	The 2023 Notes are accounted for in accordance with FASB ASC Subtopic 470‑20, Debt with Conversion and Other Options. Pursuant to ASC Subtopic 470‑20, issuers of certain convertible debt instruments, such as the 2023 Notes, that have a net settlement feature and may be settled wholly or partially in cash upon conversion are required to separately account for the liability (debt) and equity (conversion option) components of the instrument. The carrying amount of the liability component of the instrument is computed by estimating the fair value of a similar liability without the conversion option. The amount of the equity component is then calculated by deducting the fair value of the liability component from the principal amount of the instrument. The difference between the principal amount and the liability component represents a debt discount that is amortized to interest expense over the respective term of the 2023 Notes using the effective interest rate method. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. In accounting for the issuance costs related to the 2023 Notes, the allocation amount of issuance costs incurred to liability and equity components was based on their relative values.
Recently Adopted, Significant and Not Yet Adopted Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). Topic 606 supersedes the revenue recognition requirements in Accounting Standards Codification (ASC) Topic 605, Revenue Recognition (Topic 605), and requires the recognition of revenue when promised goods or services are transferred to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. Topic 606 also includes Subtopic 340-40, Other Assets and Deferred Costs - Contracts with Customers, which requires the deferral of incremental costs of obtaining a contract with a customer. Collectively, the Company refers to Topic 606 and Subtopic 340-40 as "ASC 606." The Company adopted the requirements of ASC 606 as of February 1, 2018, utilizing the full retrospective method of transition. Adoption of ASC 606 resulted in changes to the Company’s accounting policies for revenue recognition and deferred commissions as detailed below. The Company applied ASC 606 using a practical expedient where the consideration allocated to the remaining performance obligations or an explanation of when the Company expects to recognize that amount as revenue for all reporting periods presented before the date of the initial application is not disclosed. The impact of adopting ASC 606 on fiscal 2018 and 2017 revenue is not material. The primary impact of adopting ASC 606 relates to the deferral of incremental commission costs of obtaining contracts. Under Topic 605, the Company deferred only direct and incremental commission costs to obtain a contract and amortized those costs on a straight-line basis over the term of the related contract, which was generally one to three years. Under ASC 606, the Company defers all incremental commission costs to obtain the contract. The Company amortizes these costs on a straight-line basis over a period of benefit, determined to be generally five years or the related contractual renewal term. The Company adjusted its condensed consolidated financial statements from amounts previously reported due to the adoption of ASC 606. Select condensed consolidated statement of operations line items, which reflect the adoption of ASC 606, are as follows (in thousands except per share data): Three Months Ended July 31, 2017 Six Months Ended July 31, 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted (unaudited) (unaudited) Revenue: Subscription $ 56,080 $ (763 ) $ 55,317 $ 104,437 $ (841 ) $ 103,596 Professional services and other 4,915 27 4,942 9,565 (577 ) 8,988 Total revenue 60,995 (736 ) 60,259 114,002 (1,418 ) 112,584 Gross profit 41,313 (736 ) 40,577 76,857 (1,418 ) 75,439 Operating expenses: Sales and marketing 39,597 (1,706 ) 37,891 76,777 (3,583 ) 73,194 Total operating expenses 68,468 (1,706 ) 66,762 132,646 (3,583 ) 129,063 Loss before income taxes (26,773 ) 970 (25,803 ) (55,426 ) 2,165 (53,261 ) Net loss (27,002 ) 970 (26,032 ) (55,903 ) 2,165 (53,738 ) Net loss per share, basic and diluted (0.29 ) 0.01 (0.28 ) (0.83 ) 0.03 (0.80 ) Select condensed consolidated balance sheet line items, which reflect the adoption of ASC 606, are as follows (in thousands): As of January 31, 2018 As Reported Adjustments As Adjusted (unaudited) Assets Current assets: Deferred commissions $ 16,481 $ 1,274 $ 17,755 Prepaid expenses and other current assets 16,973 808 17,781 Total current assets 315,416 2,082 317,498 Deferred commissions, noncurrent 10,971 29,784 40,755 Total assets 367,397 31,866 399,263 Liabilities and stockholders’ equity Current liabilities: Deferred revenue $ 162,633 $ (2,817 ) $ 159,816 Total current liabilities 190,760 (2,817 ) 187,943 Deferred revenue, noncurrent 6,034 (1,071 ) 4,963 Total liabilities 203,811 (3,888 ) 199,923 Accumulated deficit (402,468 ) 35,754 (366,714 ) Total stockholders’ equity 163,586 35,754 199,340 Total liabilities and stockholders’ equity 367,397 31,866 399,263 The adoption of ASC 606 had no impact on cash provided by or used in operating, financing, or investing activities in the Company’s condensed consolidated statement of cash flows. Additionally, the adoption of ASC 606 did not have a material impact on the provision for (benefit from) income taxes. The adoption adjustments impacted the deferred income taxes pertaining to the U.S. entity which are subject to a full valuation allowance. Significant Accounting Policies The Company’s significant accounting policies are discussed in “Note 2. Summary of Significant Accounting Policies” in Item 8. Financial Statements and Supplementary Data of its Form 10-K for the fiscal year ended January 31, 2018. Except for the accounting policies for revenue recognition and deferred commissions that were updated below as a result of adopting ASC 606, and the accounting policies for convertible senior notes, there have been no significant changes to these policies for the six months ended July 31, 2018 . Revenue Recognition The Company derives revenue from subscription fees (which include support fees) and professional services fees. The Company sells subscriptions to its platform through arrangements that are generally one to five years in length. The Company’s arrangements are generally noncancelable and nonrefundable. Furthermore, if a customer reduces the contracted usage or service level, the customer has no right of refund. The Company’s subscription arrangements do not provide customers with the right to take possession of the software supporting the platform and, as a result, are accounted for as service arrangements. This revenue recognition policy is consistent for sales generated directly with customers and sales generated indirectly through channel partners. The Company determines revenue recognition through the following steps: • 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, the Company satisfies a performance obligation Subscription Revenue Subscription revenue, which includes support, is recognized on a straight-line basis over the noncancelable contractual term of the arrangement, generally beginning on the date that the Company’s service is made available to the customer. Professional Services Revenue The Company’s professional services principally consist of customer-specific requests for application integrations, user interface enhancements and other customer-specific requests. Revenue for the Company’s professional services are recognized as services are performed in proportion with their pattern of transfer. Contracts with Multiple Performance Obligations Some of the Company’s contracts with customers contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative SSP basis. The Company determines SSP based on, if available, observable prices for those related services when sold separately. When observable prices are not available, the Company determines SSP based on overarching pricing objectives and strategies, taking into consideration market conditions and other factors, including customer size, volume purchased, market and industry conditions, product-specific factors and historical sales of the deliverables. Geographic Information Revenue by location is determined by the billing address of the customer. The following table sets forth revenue in dollars by geographic area (in thousands): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 As Adjusted (1) As Adjusted (1) United States $ 79,499 $ 50,972 $ 150,757 $ 95,943 International 15,087 9,287 27,450 16,641 Total $ 94,586 $ 60,259 $ 178,207 $ 112,584 _______________________________ (1) T he prior periods presented above have been adjusted to reflect the adoption of ASC 606 . Other than the United States, no individual country exceeded 10% of total revenue for the three and six months ended July 31, 2018 and 2017 . Accounts Receivable and Allowances Accounts receivable are recorded at the invoiced amount, net of allowances. These allowances are based on the Company’s assessment of the collectability of accounts by considering the age of each outstanding invoice and the collection history of each customer and an evaluation of potential risk of loss associated with delinquent accounts. Amounts deemed uncollectible are recorded to these allowances in the condensed consolidated balance sheets with an offsetting decrease in related deferred revenue or a charge in the condensed consolidated statement of operations. For the three and six months ended July 31, 2018 and 2017 , write-offs were not material. Deferred Commissions Sales commissions earned by the Company’s sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions for new revenue contracts, including incremental sales to existing customers, are deferred and then amortized on a straight-line basis over a period of benefit, which the Company has determined to be generally five years. The Company determined the period of benefit by taking into consideration its customer contracts, its technology and other factors. Sales commissions for renewal contracts (which are not considered commensurate with sales commissions for new revenue contracts and incremental sales to existing customers) are deferred and then amortized on a straight-line basis over the related period of benefit, which is generally the related contract renewal term. Amortization expense is included in sales and marketing expenses in the accompanying condensed consolidated statements of operations. Sales commissions capitalized as contract costs totaled $8.5 million and $5.3 million in the three months ended July 31, 2018 and 2017 , respectively, and $14.2 million and $9.5 million in the six months ended July 31, 2018 and 2017 , respectively. Amortization of contract costs was $5.0 million and $3.7 million for the three months ended July 31, 2018 and 2017 , respectively, and $9.6 million and $7.0 million for the six months ended July 31, 2018 and 2017 , respectively. There was no impairment loss in relation to the costs capitalized. Convertible Senior Notes The 2023 Notes are accounted for in accordance with FASB ASC Subtopic 470‑20, Debt with Conversion and Other Options. Pursuant to ASC Subtopic 470‑20, issuers of certain convertible debt instruments, such as the 2023 Notes, that have a net settlement feature and may be settled wholly or partially in cash upon conversion are required to separately account for the liability (debt) and equity (conversion option) components of the instrument. The carrying amount of the liability component of the instrument is computed by estimating the fair value of a similar liability without the conversion option. The amount of the equity component is then calculated by deducting the fair value of the liability component from the principal amount of the instrument. The difference between the principal amount and the liability component represents a debt discount that is amortized to interest expense over the respective term of the 2023 Notes using the effective interest rate method. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. In accounting for the issuance costs related to the 2023 Notes, the allocation amount of issuance costs incurred to liability and equity components was based on their relative values. Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02 (Topic 842). Topic 842 amends a number of aspects of lease accounting, including requiring lessees to recognize leases with a term greater than one year as a right-of-use asset and corresponding liability, measured at the present value of the lease payments. In July 2018, the FASB issued supplemental adoption guidance and clarification to Topic 842 within ASU 2018-10 “Codification Improvements to Topic 842, Leases” and ASU 2018-11 “Leases (Topic 842): Targeted Improvements.” The new guidance aims to increase transparency and comparability among organizations by requiring lessees to recognize lease assets and lease liabilities on the balance sheet and requiring disclosure of key information about leasing arrangements. A modified retrospective application is required with an option to not restate comparative periods in the period of adoption. This guidance is effective for the Company on February 1, 2019 with early adoption permitted. The Company is currently evaluating the impact of the adoption of this standard on its consolidated financial statements, which will consist primarily of a balance sheet gross up of its operating leases to show equal and offsetting right-of-use assets and lease liabilities. In February 2018, the FASB issued ASU No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (ASU 2018-02). Under existing U.S. GAAP, the effects of changes in tax rates and laws on deferred tax balances are recorded as a component of income tax expense in the period in which the law was enacted. When deferred tax balances related to items originally recorded in accumulated other comprehensive income (loss) are adjusted, certain tax effects become stranded in accumulated other comprehensive income. The amendments in ASU 2018-02 allow a reclassification from accumulated other comprehensive income (loss) to retained earnings (accumulated deficit) for stranded income tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act). The amendments in this ASU also require certain disclosures about stranded income tax effects. The guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption in any period is permitted. The Company’s provisional adjustments recorded in fiscal year 2018 to account for the impact of the Tax Act did not result in stranded tax effects. The Company does not anticipate that the adoption of this standard will have a material impact on its condensed consolidated financial statements.

Accounting Standards and Sign20

Accounting Standards and Significant Accounting Policies (Tables)	6 Months Ended
	Jul. 31, 2018
Accounting Policies [Abstract]
Schedule of Impact of New Accounting Pronouncements	The Company adjusted its condensed consolidated financial statements from amounts previously reported due to the adoption of ASC 606. Select condensed consolidated statement of operations line items, which reflect the adoption of ASC 606, are as follows (in thousands except per share data): Three Months Ended July 31, 2017 Six Months Ended July 31, 2017 As Reported Adjustments As Adjusted As Reported Adjustments As Adjusted (unaudited) (unaudited) Revenue: Subscription $ 56,080 $ (763 ) $ 55,317 $ 104,437 $ (841 ) $ 103,596 Professional services and other 4,915 27 4,942 9,565 (577 ) 8,988 Total revenue 60,995 (736 ) 60,259 114,002 (1,418 ) 112,584 Gross profit 41,313 (736 ) 40,577 76,857 (1,418 ) 75,439 Operating expenses: Sales and marketing 39,597 (1,706 ) 37,891 76,777 (3,583 ) 73,194 Total operating expenses 68,468 (1,706 ) 66,762 132,646 (3,583 ) 129,063 Loss before income taxes (26,773 ) 970 (25,803 ) (55,426 ) 2,165 (53,261 ) Net loss (27,002 ) 970 (26,032 ) (55,903 ) 2,165 (53,738 ) Net loss per share, basic and diluted (0.29 ) 0.01 (0.28 ) (0.83 ) 0.03 (0.80 ) Select condensed consolidated balance sheet line items, which reflect the adoption of ASC 606, are as follows (in thousands): As of January 31, 2018 As Reported Adjustments As Adjusted (unaudited) Assets Current assets: Deferred commissions $ 16,481 $ 1,274 $ 17,755 Prepaid expenses and other current assets 16,973 808 17,781 Total current assets 315,416 2,082 317,498 Deferred commissions, noncurrent 10,971 29,784 40,755 Total assets 367,397 31,866 399,263 Liabilities and stockholders’ equity Current liabilities: Deferred revenue $ 162,633 $ (2,817 ) $ 159,816 Total current liabilities 190,760 (2,817 ) 187,943 Deferred revenue, noncurrent 6,034 (1,071 ) 4,963 Total liabilities 203,811 (3,888 ) 199,923 Accumulated deficit (402,468 ) 35,754 (366,714 ) Total stockholders’ equity 163,586 35,754 199,340 Total liabilities and stockholders’ equity 367,397 31,866 399,263
Schedule of Revenue by Geographical Area	Revenue by location is determined by the billing address of the customer. The following table sets forth revenue in dollars by geographic area (in thousands): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 As Adjusted (1) As Adjusted (1) United States $ 79,499 $ 50,972 $ 150,757 $ 95,943 International 15,087 9,287 27,450 16,641 Total $ 94,586 $ 60,259 $ 178,207 $ 112,584 _______________________________ (1) T he prior periods presented above have been adjusted to reflect the adoption of ASC 606 .

Cash Equivalents and Short-Te21

Cash Equivalents and Short-Term Investments (Tables)	6 Months Ended
	Jul. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Costs, Unrealized Gains and Losses and Estimated Fair Value of Cash Equivalents and Short-term Investments	The amortized cost, unrealized gain (loss) and estimated fair value of the Company’s cash equivalents and short-term investments as of July 31, 2018 and January 31, 2018 were as follows (in thousands): As of July 31, 2018 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value (unaudited) Cash equivalents: Money market funds $ 155,347 $ — $ — $ 155,347 Commercial paper 12,237 — — 12,237 Total cash equivalents $ 167,584 $ — $ — $ 167,584 Short-term investments: Commercial paper $ 56,191 $ — $ — $ 56,191 U.S. treasury securities 248,081 — (217 ) 247,864 Corporate debt securities 39,352 6 (39 ) 39,319 Total short-term investments 343,624 6 (256 ) 343,374 Total $ 511,208 $ 6 $ (256 ) $ 510,958 As of January 31, 2018 Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Cash equivalents: Money market funds $ 90,770 $ — $ — $ 90,770 Total cash equivalents $ 90,770 $ — $ — $ 90,770 Short-term investments: Commercial paper $ 15,946 $ — $ — $ 15,946 U.S. treasury securities 61,896 — (158 ) 61,738 Corporate debt securities 24,125 — (44 ) 24,081 Total short-term investments 101,967 — (202 ) 101,765 Total $ 192,737 $ — $ (202 ) $ 192,535
Schedule of Contractual Maturities of Short-term Investments	The following tables present the contractual maturities of the Company’s short-term investments as of July 31, 2018 and January 31, 2018 (in thousands): As of July 31, 2018 As of January 31, 2018 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value (unaudited) Due within one year $ 328,694 $ 328,460 $ 93,421 $ 93,237 Due between one to five years 14,930 14,914 8,546 8,528 $ 343,624 $ 343,374 $ 101,967 $ 101,765

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jul. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis using the above input categories (in thousands): As of July 31, 2018 Level 1 Level 2 Level 3 Total (unaudited) Assets: Cash equivalents: Money market funds $ 155,347 $ — $ — $ 155,347 Commercial paper — 12,237 — 12,237 Total cash equivalents $ 155,347 $ 12,237 $ — $ 167,584 Short-term investments: Commercial paper $ — $ 56,191 $ — $ 56,191 U.S. treasury securities — 247,864 — 247,864 Corporate debt securities — 39,319 — 39,319 Total short-term investments — 343,374 — 343,374 Total cash equivalents and short-term investments $ 155,347 $ 355,611 $ — $ 510,958 As of January 31, 2018 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 90,770 $ — $ — $ 90,770 Total cash equivalents $ 90,770 $ — $ — $ 90,770 Short-term investments: Commercial paper $ — $ 15,946 $ — $ 15,946 U.S. treasury securities — 61,738 — 61,738 Corporate debt securities — 24,081 — 24,081 Total short-term investments — 101,765 — 101,765 Total cash equivalents and short-term investments $ 90,770 $ 101,765 $ — $ 192,535
Schedule of Carrying Amounts and Estimated Fair Values of Convertible Note	The following table presents the carrying amounts and estimated fair values of our financial instruments that are not recorded at fair value on the condensed consolidated balance sheets (in thousands): As of July 31, 2018 Net Carrying Amount Before Unamortized Debt Issuance Costs Estimated Fair Value (unaudited) Convertible senior notes $ 270,972 $ 421,800

Goodwill and Intangible Asset23

Goodwill and Intangible Assets, net (Tables)	6 Months Ended
	Jul. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets, net	Intangible assets consisted of the following (in thousands): As of July 31, 2018 Gross Accumulated Amortization Net (unaudited) Capitalized internal-use software costs $ 18,467 $ (7,441 ) $ 11,026 Purchased developed technology 5,170 (570 ) 4,600 Software licenses 1,023 (643 ) 380 $ 24,660 $ (8,654 ) $ 16,006 As of January 31, 2018 Gross Accumulated Amortization Net Capitalized internal-use software costs $ 16,434 $ (5,172 ) $ 11,262 Software licenses 1,057 (558 ) 499 Purchased developed technology 570 (570 ) — $ 18,061 $ (6,300 ) $ 11,761

Debt and Financing Arrangemen24

Debt and Financing Arrangements (Tables)	6 Months Ended
	Jul. 31, 2018
Debt Disclosure [Abstract]
Schedule of Interest Expense	The following table sets forth total interest expense recognized related to the 2023 Notes (in thousands): Three Months Ended July 31, 2018 Six Months Ended July 31, 2018 (unaudited) Contractual interest expense $ 216 $ 362 Amortization of debt issuance costs 288 478 Amortization of debt discount 3,554 5,935 Total $ 4,058 $ 6,775
Schedule of Liability and Equity Component of 2023 Notes	The 2023 Notes, net consisted of the following (in thousands): As of July 31, 2018 (unaudited) Liability component: Principal $ 345,000 Less: unamortized debt issuance costs and debt discount (81,238 ) Net carrying amount $ 263,762 At Issuance (unaudited) Equity component: 2023 Notes $ 79,962 Less: issuance costs (2,320 ) Carrying amount of the equity component (1) $ 77,642 (1) Included in the condensed consolidated balance sheets within Additional paid-in capital.

Employee Incentive Plans (Table

Employee Incentive Plans (Tables)	6 Months Ended
	Jul. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock-based Compensation Expense by Statement of Operations Location	Stock-based compensation expense was recorded in the following cost and expense categories in the Company’s condensed consolidated statements of operations (in thousands): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 (unaudited) Cost of revenue Subscription $ 1,901 $ 1,056 $ 3,430 $ 1,742 Professional services and other 1,083 738 1,972 1,207 Research and development 5,272 4,438 9,485 7,739 Sales and marketing 5,471 3,021 9,624 5,396 General and administrative 4,495 2,725 7,846 4,800 Total $ 18,222 $ 11,978 $ 32,357 $ 20,884
Schedule of Shares of Common Stock Reserved for Future Issuance	Shares of common stock reserved for future issuance are as follows: As of July 31, 2018 (unaudited) Stock options and unvested RSUs outstanding 25,789,276 Available for future stock option and RSU grants 12,464,154 Available for ESPP 3,035,697 41,289,127
Schedule of Stock Option Activity	A summary of the Company’s stock option activity and related information is as follows: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding as of January 31, 2018 24,917,045 $ 7.37 7.6 $ 550,173 Granted 684,500 39.21 Exercised (4,025,395 ) 5.23 Canceled (677,660 ) 8.41 Outstanding as of July 31, 2018 (unaudited) 20,898,490 $ 8.79 7.4 $ 853,892 As of July 31, 2018 Vested and exercisable (unaudited) 9,797,292 $ 6.35 6.8 $ 424,203
Schedule of Black-Scholes Option Pricing Model Estimated Fair Value Assumptions	The Company used the Black-Scholes option pricing model to estimate the fair value of stock options granted with the following assumptions: Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 (unaudited) Expected volatility — — 40% 40% - 41% Expected term (in years) — — 6.25 6.0 - 6.4 Risk-free interest rate — — 2.70% 2.06% - 2.21% Expected dividend yield — — — — The Company estimated the fair value of ESPP purchase rights using a Black-Scholes option pricing model with the following assumptions: Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 (unaudited) Expected volatility 39% - 40% 32% - 34% 39% - 40% 32% - 37% Expected term (in years) 0.5 - 1.0 0.5 - 1.0 0.5 - 1.0 0.5 - 1.2 Risk-free interest rate 2.12% - 2.34% 1.12% - 1.22% 2.12% - 2.34% 0.95% - 1.22% Expected dividend yield — — — —
Schedule of Nonvested Restricted Stock Units Activity	A summary of the Company’s RSU activity and related information is as follows: Number of Weighted- Outstanding as of January 31, 2018 2,862,929 $ 24.38 Granted 2,752,588 50.67 Vested (542,969 ) 22.71 Forfeited (181,762 ) 29.39 Outstanding as of July 31, 2018 (unaudited) 4,890,786 $ 39.17

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jul. 31, 2018
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share	The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Three Months Ended July 31, Six Months Ended July 31, 2018 2017 2018 2017 Class A Class B Class A Class B Class A Class B Class A Class B (unaudited) Numerator: Net loss (1) $ (33,862 ) $ (5,345 ) $ (4,075 ) $ (21,957 ) $ (53,242 ) $ (11,927 ) $ (7,254 ) $ (46,484 ) Denominator: Weighted-average shares outstanding - basic and diluted 92,156 14,546 14,650 78,926 86,172 19,303 9,061 58,064 Net loss per share attributable to common stockholders, basic and diluted $ (0.37 ) $ (0.37 ) $ (0.28 ) $ (0.28 ) $ (0.62 ) $ (0.62 ) $ (0.80 ) $ (0.80 ) (1) Net loss for the three and six months ended July 31, 2017 has been adjusted. See Note 2 for a summary of adjustments.
Schedule of Potentially Dilutive Securities Excluded from Diluted Per Share Calculation	Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows (in thousands): As of July 31, 2018 2017 (unaudited) Unvested restricted common stock issued and outstanding 400 800 Stock options issued and outstanding 20,898 33,360 Unvested RSUs issued and outstanding 4,891 2,210 Unvested restricted stock awards issued and outstanding 388 599 Shares related to convertible senior notes 7,134 — Shares committed under the ESPP 360 1,082 Unvested shares subject to repurchase 96 324 34,167 38,375

Overview and Basis of Present27

Overview and Basis of Presentation - Narrative (Details) - USD ($)	Feb. 23, 2018	Apr. 07, 2017	Apr. 06, 2017	Jul. 31, 2018	Jul. 31, 2017	[1]
Class of Stock [Line Items]
Initial public offering costs				$ 0	$ 4,038,000
Class A Common Stock
Class of Stock [Line Items]
Price per share in initial public offering (in dollars per share)		$ 17
Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Redeemable convertible preferred stock converted to common class B stock (in shares)			59,491,640
Class B Common Stock
Class of Stock [Line Items]
Common class B stock after conversion of redeemable convertible stock (in shares)			59,491,640
Initial Public Offering
Class of Stock [Line Items]
Proceeds from initial public offering, net of underwriters' discounts and commissions		$ 200,000,000
Initial public offering costs		$ 5,600,000
Initial Public Offering | Class A Common Stock
Class of Stock [Line Items]
Shares issued in initial public offering (in shares)		12,650,000
Convertible Senior Notes Due 2023 | Senior Notes
Class of Stock [Line Items]
Aggregate principal amount	$ 345,000,000
Fixed interest rate	0.25%
Gross proceeds from issuance of debt	$ 345,000,000
Issuance costs	$ 10,000,000			$ 10,000,000
[1]	See Note 2 for a summary of adjustments.

Accounting Standards and Sign28

Accounting Standards and Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Jan. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract cost, amortization period			5 years
Sales commissions capitalized as contract costs	$ 8,500,000	$ 5,300,000	$ 14,200,000	$ 9,500,000
Amortization of capitalized contract costs	5,000,000	3,700,000	9,600,000	7,000,000
Capitalized contract cost, impairment loss	$ 0	$ 0	$ 0	$ 0
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract duration			1 year
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract duration			5 years
Calculated under Revenue Guidance in Effect before Topic 606 | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract cost, amortization period					1 year
Calculated under Revenue Guidance in Effect before Topic 606 | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized contract cost, amortization period					3 years

Accounting Standards and Sign29

Accounting Standards and Significant Accounting Policies - Schedule of Impact of New Accounting Pronouncements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017		Jul. 31, 2018	Jul. 31, 2017		Jan. 31, 2018
Revenue:
Subscription	$ 87,854	$ 55,317	[1]	$ 164,695	$ 103,596	[1]
Professional services and other	6,732	4,942	[1]	13,512	8,988	[1]
Total revenue	94,586	60,259	[1]	178,207	112,584	[1]
Gross profit	66,358	40,577	[1]	125,872	75,439	[1]
Operating expenses:
Sales and marketing	59,004	37,891	[1]	108,497	73,194	[1]
Total operating expenses	104,788	66,762	[1]	189,280	129,063	[1]
Loss before provision for (benefit from) income taxes	(40,192)	(25,803)	[1]	(66,385)	(53,261)	[1]
Net loss	$ (39,207)	$ (26,032)	[1],[2]	$ (65,169)	$ (53,738)	[1],[3]
Net loss per share, basic and diluted (in dollars per share)	$ (0.37)	$ (0.28)	[1]	$ (0.62)	$ (0.80)	[1]
Current assets:
Deferred commissions	$ 19,848			$ 19,848			$ 17,755	[4]
Prepaid expenses and other current assets	17,433			17,433			17,781	[4]
Total current assets	633,376			633,376			317,498	[4]
Deferred commissions, noncurrent	43,287			43,287			40,755	[4]
Total assets	763,917			763,917			399,263	[4]
Current liabilities:
Deferred revenue	186,427			186,427			159,816	[4]
Total current liabilities	218,140			218,140			187,943	[4]
Deferred revenue, noncurrent	5,471			5,471			4,963	[4]
Total liabilities	518,772			518,772			199,923	[4]
Accumulated deficit	(431,883)			(431,883)			(366,714)	[4]
Total stockholders’ equity	245,145			245,145			199,340	[4]
Total liabilities and stockholders’ equity	$ 763,917			$ 763,917			399,263	[4]
As Reported
Revenue:
Subscription		$ 56,080			$ 104,437
Professional services and other		4,915			9,565
Total revenue		60,995			114,002
Gross profit		41,313			76,857
Operating expenses:
Sales and marketing		39,597			76,777
Total operating expenses		68,468			132,646
Loss before provision for (benefit from) income taxes		(26,773)			(55,426)
Net loss		$ (27,002)			$ (55,903)
Net loss per share, basic and diluted (in dollars per share)		$ (0.29)			$ (0.83)
Current assets:
Deferred commissions							16,481
Prepaid expenses and other current assets							16,973
Total current assets							315,416
Deferred commissions, noncurrent							10,971
Total assets							367,397
Current liabilities:
Deferred revenue							162,633
Total current liabilities							190,760
Deferred revenue, noncurrent							6,034
Total liabilities							203,811
Accumulated deficit							(402,468)
Total stockholders’ equity							163,586
Total liabilities and stockholders’ equity							367,397
Accounting Standards Update 2014-09 | Adjustments
Revenue:
Subscription		$ (763)			$ (841)
Professional services and other		27			(577)
Total revenue		(736)			(1,418)
Gross profit		(736)			(1,418)
Operating expenses:
Sales and marketing		(1,706)			(3,583)
Total operating expenses		(1,706)			(3,583)
Loss before provision for (benefit from) income taxes		970			2,165
Net loss		$ 970			$ 2,165
Net loss per share, basic and diluted (in dollars per share)		$ 0.01			$ 0.03
Current assets:
Deferred commissions							1,274
Prepaid expenses and other current assets							808
Total current assets							2,082
Deferred commissions, noncurrent							29,784
Total assets							31,866
Current liabilities:
Deferred revenue							(2,817)
Total current liabilities							(2,817)
Deferred revenue, noncurrent							(1,071)
Total liabilities							(3,888)
Accumulated deficit							35,754
Total stockholders’ equity							35,754
Total liabilities and stockholders’ equity							$ 31,866
[1]	See Note 2 for a summary of adjustments.
[2]	See Note 2 for a summary of adjustments.
[3]	See Note 2 for a summary of adjustments.
[4]	See Note 2 for a summary of adjustments.

Accounting Standards and Sign30

Accounting Standards and Significant Accounting Policies - Revenue by Geographical Area (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017		Jul. 31, 2018	Jul. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue by geographical area	$ 94,586	$ 60,259	[1]	$ 178,207	$ 112,584	[1]
United States
Disaggregation of Revenue [Line Items]
Revenue by geographical area	79,499	50,972		150,757	95,943
International
Disaggregation of Revenue [Line Items]
Revenue by geographical area	$ 15,087	$ 9,287		$ 27,450	$ 16,641
[1]	See Note 2 for a summary of adjustments.

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($) $ in Thousands	Jul. 13, 2018	Feb. 17, 2017	Jul. 31, 2018	Jul. 31, 2018	Jul. 31, 2017	[1]	Jan. 31, 2018	[2]
Business Acquisition [Line Items]
Payments for business acquisition, net of cash acquired				$ 15,638	$ 0
Goodwill			$ 18,095	$ 18,095			$ 6,282
Stormpath Inc.
Business Acquisition [Line Items]
Total purchase price		$ 3,700
Shares included in total consideration (in shares)		200,000
Stormpath Inc. | Restricted common stock
Business Acquisition [Line Items]
Incremental shares issued (in shares)		800,000
Incremental shares issued		$ 8,600
Stormpath Inc. | Stormpath Investors
Business Acquisition [Line Items]
Total purchase price		2,200
Stormpath Inc. | Stormpath Workforce
Business Acquisition [Line Items]
Total purchase price		1,500
Incremental shares issued		$ 9,100
ScaleFT, Inc.
Business Acquisition [Line Items]
Payments for business acquisition, net of cash acquired	$ 15,600
Cash acquired from acquisition	600
Purchased developed technology	4,600
Goodwill	11,800
Acquisition related costs			$ 1,100
ScaleFT, Inc. | Purchased developed technology
Business Acquisition [Line Items]
Purchased developed technology	$ 4,600
Useful life of acquired intangible assets	3 years
[1]	See Note 2 for a summary of adjustments.
[2]	See Note 2 for a summary of adjustments.

Cash Equivalents and Short-Te32

Cash Equivalents and Short-Term Investments - Schedule of Amortized Costs, Unrealized Gains and Losses and Estimated Fair Value of Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	$ 343,624	$ 101,967
Unrealized Gain	6	0
Unrealized Loss	(256)	(202)
Estimated Fair Value	343,374	101,765
Total Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	511,208	192,737
Unrealized Gain	6	0
Unrealized Loss	(256)	(202)
Estimated Fair Value	510,958	192,535
Commercial paper
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	56,191	15,946
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	56,191	15,946
U.S. treasury securities
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	248,081	61,896
Unrealized Gain	0	0
Unrealized Loss	(217)	(158)
Estimated Fair Value	247,864	61,738
Corporate debt securities
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	39,352	24,125
Unrealized Gain	6	0
Unrealized Loss	(39)	(44)
Estimated Fair Value	39,319	24,081
Cash Equivalents
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	167,584	90,770
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	167,584	90,770
Cash Equivalents | Money market funds
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	155,347	90,770
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	155,347	$ 90,770
Cash Equivalents | Commercial paper
Cash Equivalents and Short-term Investments [Abstract]
Amortized Cost	12,237
Unrealized Gain	0
Unrealized Loss	0
Estimated Fair Value	$ 12,237

Cash Equivalents and Short-Te33

Cash Equivalents and Short-Term Investments - Schedule of Contractual Maturities of Short-term Investments (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018
Amortized Cost
Amortized cost, due within one year	$ 328,694	$ 93,421
Amortized cost, due between one to five years	14,930	8,546
Amortized cost, total	343,624	101,967
Estimated Fair Value
Estimated fair value, due within one year	328,460	93,237
Estimated fair value, due between one to five years	14,914	8,528
Estimated fair value, total	$ 343,374	$ 101,765

Cash Equivalents and Short-Te34

Cash Equivalents and Short-Term Investments - Narrative (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2018USD ($)investment	Jul. 31, 2017USD ($)	Jul. 31, 2018USD ($)investment	Jul. 31, 2017USD ($)	Jan. 31, 2018USD ($)investment
Investments, Debt and Equity Securities [Abstract]
Number of short-term investments in unrealized loss positions | investment	53		53		23
Gross unrealized gains or losses from available-for-sale securities	$ 0	$ 0	$ 0	$ 0
Realized gains or losses reclassified out of accumulated other comprehensive income	$ 0	$ 0	0	$ 0
Other-than-temporary impairment short term investment			$ 0		$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018
Assets:
Cash equivalents, fair value	$ 167,584	$ 90,770
Short term investments, fair value	343,374	101,765
Total cash equivalents and short-term investments	510,958	192,535
Level 1
Assets:
Cash equivalents, fair value	155,347	90,770
Short term investments, fair value	0	0
Total cash equivalents and short-term investments	155,347	90,770
Level 2
Assets:
Cash equivalents, fair value	12,237	0
Short term investments, fair value	343,374	101,765
Total cash equivalents and short-term investments	355,611	101,765
Level 3
Assets:
Cash equivalents, fair value	0	0
Short term investments, fair value	0	0
Total cash equivalents and short-term investments	0	0
Commercial paper
Assets:
Short term investments, fair value	56,191	15,946
Commercial paper | Level 1
Assets:
Short term investments, fair value	0	0
Commercial paper | Level 2
Assets:
Short term investments, fair value	56,191	15,946
Commercial paper | Level 3
Assets:
Short term investments, fair value	0	0
U.S. treasury securities
Assets:
Short term investments, fair value	247,864	61,738
U.S. treasury securities | Level 1
Assets:
Short term investments, fair value	0	0
U.S. treasury securities | Level 2
Assets:
Short term investments, fair value	247,864	61,738
U.S. treasury securities | Level 3
Assets:
Short term investments, fair value	0	0
Corporate debt securities
Assets:
Short term investments, fair value	39,319	24,081
Corporate debt securities | Level 1
Assets:
Short term investments, fair value	0	0
Corporate debt securities | Level 2
Assets:
Short term investments, fair value	39,319	24,081
Corporate debt securities | Level 3
Assets:
Short term investments, fair value	0	0
Money market funds
Assets:
Cash equivalents, fair value	155,347	90,770
Money market funds | Level 1
Assets:
Cash equivalents, fair value	155,347	90,770
Money market funds | Level 2
Assets:
Cash equivalents, fair value	0	0
Money market funds | Level 3
Assets:
Cash equivalents, fair value	0	$ 0
Commercial paper
Assets:
Cash equivalents, fair value	12,237
Commercial paper | Level 1
Assets:
Cash equivalents, fair value	0
Commercial paper | Level 2
Assets:
Cash equivalents, fair value	12,237
Commercial paper | Level 3
Assets:
Cash equivalents, fair value	$ 0

Fair Value Measurements - Sch36

Fair Value Measurements - Schedule of Carrying Amounts and Estimated Fair Values of Convertible Note (Details) - Senior Notes - Convertible Senior Notes Due 2023 $ in Thousands	Jul. 31, 2018USD ($)
Reported Value Measurement
Debt Instrument [Line Items]
Estimated Fair Value	$ 270,972
Estimate of Fair Value Measurement
Debt Instrument [Line Items]
Estimated Fair Value	$ 421,800

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ / shares in Units, $ in Thousands	Jul. 31, 2018USD ($)$ / shares
Debt Instrument [Line Items]
Closing price of common stock (in dollars per share) | $ / shares	$ 49.65
Convertible Senior Notes Due 2023 | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount | $	$ 345,000

Goodwill and Intangible Asset38

Goodwill and Intangible Assets, net - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Jan. 31, 2018		Jan. 31, 2017	Jul. 13, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 18,095,000		$ 18,095,000		$ 6,282,000	[1]
Goodwill impairments	0	$ 0	0	$ 0
Capitalized internal-use software	800,000	1,900,000	2,000,000	3,300,000
Stock-based compensation included in capitalized software costs	100,000	400,000	$ 300,000	$ 600,000
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 1,200,000	$ 700,000			$ 2,400,000		$ 1,400,000
ScaleFT, Inc.
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill								$ 11,800,000
Finite-Lived Intangible Assets [Line Items]
Purchased developed technology								4,600,000
ScaleFT, Inc. | Purchased developed technology
Finite-Lived Intangible Assets [Line Items]
Purchased developed technology								$ 4,600,000
[1]	See Note 2 for a summary of adjustments.

Goodwill and Intangible Asset39

Goodwill and Intangible Assets, net - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jan. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross	$ 24,660	$ 18,061
Accumulated Amortization	(8,654)	(6,300)
Net	16,006	11,761
Capitalized internal-use software costs
Finite-Lived Intangible Assets [Line Items]
Gross	18,467	16,434
Accumulated Amortization	(7,441)	(5,172)
Net	11,026	11,262
Purchased developed technology
Finite-Lived Intangible Assets [Line Items]
Gross	5,170	570
Accumulated Amortization	(570)	(570)
Net	4,600	0
Software licenses
Finite-Lived Intangible Assets [Line Items]
Gross	1,023	1,057
Accumulated Amortization	(643)	(558)
Net	$ 380	$ 499

Deferred Revenue and Performa40

Deferred Revenue and Performance Obligations - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Jan. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue recognized that was included in the contract liability balance	$ 73.1	$ 46.7	$ 114.3	$ 73.3
Unbilled receivables	$ 0.8		$ 0.8		$ 0.8

Deferred Revenue and Performa41

Deferred Revenue and Performance Obligations - Performance Obligations (Details) $ in Millions	6 Months Ended
	Jul. 31, 2018USD ($)
Revenue from Contract with Customer [Abstract]
Revenue from remaining performance obligations	$ 543.9
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, percentage	56.00%
Performance obligations expected to be satisfied, expected timing	12 months

Debt and Financing Arrangemen42

Debt and Financing Arrangements - Convertible Senior Notes (Details) - Senior Notes - Convertible Senior Notes Due 2023 $ / shares in Units, $ in Thousands	Feb. 27, 2018	Feb. 23, 2018USD ($)day$ / shares	Jul. 31, 2018USD ($)
Debt Instrument [Line Items]
Fixed interest rate		0.25%
Net proceeds from notes		$ 335,000
Initial conversion rate of common stock	0.0206795
Conversion price (in dollars per share) | $ / shares		$ 48.36
Limitation on sale of common stock, sale price threshold, number of trading days | day		20
Limitation on sale of common stock, sale price threshold, trading period | day		30
Threshold percentage of stock price trigger		130.00%
Number of consecutive business days		5 days
Percentage of closing sale price in excess of convertible notes		98.00%
Redemption price percentage		100.00%
Effective interest rate		5.68%
Issuance costs		$ 10,000	$ 10,000
Issuance costs attributable to liability component			7,700
Additional Paid-in Capital
Debt Instrument [Line Items]
Issuance costs attributable to equity component			$ 2,320

Debt and Financing Arrangemen43

Debt and Financing Arrangements - Schedule of Interest Expense (Details) - Senior Notes - Convertible Senior Notes Due 2023 - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2018	Jul. 31, 2018
Debt Instrument [Line Items]
Contractual interest expense	$ 216	$ 362
Amortization of debt issuance costs	288	478
Amortization of debt discount	3,554	5,935
Total	$ 4,058	$ 6,775

Debt and Financing Arrangemen44

Debt and Financing Arrangements - Schedule of Liability and Equity Component of 2023 Notes (Details) - Senior Notes - Convertible Senior Notes Due 2023 $ in Thousands	Jul. 31, 2018USD ($)
Liability component:
Principal	$ 345,000
Less: unamortized debt issuance costs and debt discount	(81,238)
Net carrying amount	263,762
Additional Paid-in Capital
Equity component:
2023 Notes	79,962
Less: issuance costs	(2,320)
Carrying amount of the equity component	$ 77,642

Debt and Financing Arrangemen45

Debt and Financing Arrangements - Note Hedges and Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Feb. 27, 2018	Feb. 23, 2018	Jul. 31, 2018	Jul. 31, 2017	[1]
Debt Instrument [Line Items]
Aggregate amount paid for cost of Note Hedge	$ 80,000
Number of warrants issued, subject to anti-dilution adjustments (in shares)		7.1
Per share value, shares issuable under warrants granted (in dollars per share)		$ 68.06
Proceeds from issuance of warrants related to convertible notes		$ 52,400	$ 52,440	$ 0
Senior Notes | Convertible Senior Notes Due 2023
Debt Instrument [Line Items]
Shares issuable under warrants granted (in shares)		7.1
Conversion price (in dollars per share)		$ 48.36
[1]	See Note 2 for a summary of adjustments.

Debt and Financing Arrangemen46

Debt and Financing Arrangements - Loan and Security Agreement (Details) - USD ($)	6 Months Ended
	Jul. 31, 2018	Nov. 21, 2018	Jan. 31, 2018	Nov. 21, 2017	Nov. 21, 2016
Debt Instrument [Line Items]
Letters of credit issued and outstanding	$ 12,500,000		$ 12,200,000
Loan and Security Agreement | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity					$ 40,000,000
Letters of credit issued and outstanding	4,200,000
Available borrowing capacity	$ 35,800,000
Unused line of credit percentage fee	0.15%
Line of credit commitment fee				$ 100,000	$ 100,000
Draws on line of credit	$ 0		$ 0
Loan and Security Agreement | Revolving Credit Facility | Line of Credit | Prime Rate
Debt Instrument [Line Items]
Line of credit interest rate	0.75%
Scenario, Forecast | Loan and Security Agreement | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit commitment fee		$ 100,000

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended			12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017		Jan. 31, 2018	Jan. 31, 2017	Jun. 30, 2018
Other Commitments [Line Items]
Deferred rent	$ 30,500,000			$ 5,500,000
Rent expense	5,800,000	$ 2,500,000		9,200,000	$ 4,700,000
Letters of credit issued and outstanding	12,500,000			$ 12,200,000
Restricted cash	8,560,000	$ 279,000	[1]
Letter of Credit
Other Commitments [Line Items]
Draws on line of credit	0
San Francisco - Ten Year Lease
Other Commitments [Line Items]
Restricted cash	$ 8,000,000
Financial Standby Letter of Credit
Other Commitments [Line Items]
Standby letter of credit						$ 3,000,000
[1]	See Note 2 for a summary of adjustments.

Employee Incentive Plans - Sche

Employee Incentive Plans - Schedule of Stock-based Compensation Expense by Statement of Operations Location (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 18,222	$ 11,978	$ 32,357	$ 20,884
Subscription
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,901	1,056	3,430	1,742
Professional services and other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,083	738	1,972	1,207
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	5,272	4,438	9,485	7,739
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	5,471	3,021	9,624	5,396
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,495	$ 2,725	$ 7,846	$ 4,800

Employee Incentive Plans - Narr

Employee Incentive Plans - Narrative (Details)	Feb. 17, 2017USD ($)shares	Mar. 31, 2017offering_period	Feb. 28, 2017USD ($)shares	Jul. 31, 2018USD ($)$ / sharesshares	Jul. 31, 2017USD ($)shares	Jul. 31, 2018USD ($)incentive_plan$ / sharesshares	Jul. 31, 2017USD ($)$ / sharesshares		Jan. 31, 2018USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans | incentive_plan						2
Options to purchase common stock outstanding (in shares) | shares				20,898,490		20,898,490			24,917,045
Weighted average grant date fair value of options granted (in dollars per share) | $ / shares						$ 17.21	$ 5.36
Grant date fair value of vested stock options				$ 7,800,000	$ 8,400,000	$ 13,500,000	$ 13,000,000
Intrinsic value of options exercised				73,200,000	$ 5,300,000	155,100,000	19,300,000
Unrecognized stock-based compensation expense related to stock options				$ 50,900,000		$ 50,900,000
Number of options, granted (in shares) | shares						684,500
Issuance of common stock under employee stock purchase plan						$ 6,700,000
General and administrative expense recognized						$ 1,008,000	$ 0	[1]
Class A Common Stock | Contribution of Nonmonetary Assets to Charitable Organization
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued as charitable contribution (in shares) | shares				20,000	0	20,000	0
General and administrative expense recognized				$ 1,000,000	$ 0	$ 1,000,000	$ 0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period									3 years 5 months 9 days
Unrecognized compensation costs related to unvested restricted stock units									$ 180,200,000
Granted during period (in shares) | shares						2,752,588
Vested during period (in shares) | shares						542,969
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						2 years 3 months 4 days
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						7 months 28 days
Unrecognized compensation costs related to unvested restricted stock units				$ 5,300,000		$ 5,300,000
ESPP offering period		12 months
Number of offering periods | offering_period		2
ESPP length of purchase period		6 months
Shares issued under ESPP (in shares) | shares				434,640		434,640
Weighted average price, shares issued under ESPP (in usd per share) | $ / shares				$ 15.31		$ 15.31
Stormpath Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-combination service consideration	$ 3,700,000
Stormpath Inc. | Restricted common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted during period (in shares) | shares	800,000
Shares issued fair value	$ 8,600,000
Stormpath Inc. | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						7 months 6 days
Unrecognized compensation costs related to unvested restricted stock units				$ 1,200,000		$ 1,200,000
Vested during period (in shares) | shares						400,000
Stormpath Inc. | Stormpath Workforce
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to stock options			$ 2,100,000	1,400,000		$ 1,400,000
Shares issued fair value	9,100,000
Pre-combination service consideration	$ 1,500,000
Stormpath Inc. | Stormpath Workforce | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						1 year 4 days
Unrecognized compensation costs related to unvested restricted stock units			$ 5,500,000	$ 1,400,000		$ 1,400,000
Granted during period (in shares) | shares			598,500
Shares issued fair value			$ 6,600,000
Vested during period (in shares) | shares						210,850
Stormpath Inc. | Stormpath Workforce | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						1 year 10 months 24 days
Shares issued fair value			$ 2,500,000
Stock-based compensation vesting period			4 years
Number of options, granted (in shares) | shares			518,900
Minimum | Stormpath Inc. | Stormpath Workforce | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation vesting period			2 years
Maximum | Stormpath Inc. | Stormpath Workforce | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation vesting period			3 years
2009 Stock Plan | Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock outstanding (in shares) | shares				20,133,894		20,133,894
2017 Equity Incentive Plan | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock outstanding (in shares) | shares				764,596		764,596
[1]	See Note 2 for a summary of adjustments.

Employee Incentive Plans - Sc50

Employee Incentive Plans - Schedule of Common Stock Reserved for Future Issuance (Details)	Jul. 31, 2018shares
Class of Stock [Line Items]
Common stock reserved for future issuance and options and unvested RSUs outstanding (in shares)	41,289,127
Stock Options And Restricted Stock Units
Class of Stock [Line Items]
Stock options and unvested RSUs outstanding (in shares)	25,789,276
Common stock, reserved for future issuance (in shares)	12,464,154
ESPP
Class of Stock [Line Items]
Common stock, reserved for future issuance (in shares)	3,035,697

Employee Incentive Plans - Sc51

Employee Incentive Plans - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 31, 2018	Jan. 31, 2018
Number of Options
Number of options, outstanding beginning of period (in shares)	24,917,045
Number of options, granted (in shares)	684,500
Number of options, exercised (in shares)	(4,025,395)
Number of options, canceled (in shares)	(677,660)
Number of options, outstanding end of period (in shares)	20,898,490	24,917,045
Vested and exercisable, number of options (in shares)	9,797,292
Weighted- Average Exercise Price
Options outstanding, weighted average exercise price beginning of period (in dollars per share)	$ 7.37
Options granted, weighted average exercise price (in dollars per share)	39.21
Options exercised, weighted average exercise price (in dollars per share)	5.23
Options canceled, weighted average exercise price (in dollars per share)	8.41
Options outstanding, weighted average exercise price end of period (in dollars per share)	8.79	$ 7.37
Vested and exercisable, weighted average exercise price (in dollars per share)	$ 6.35
Additional Disclosures
Options outstanding, weighted average remaining contractual term	7 years 4 months 13 days	7 years 7 months 21 days
Options outstanding, aggregate intrinsic value	$ 853,892	$ 550,173
Vested and exercisable, weighted average remaining contractual term	6 years 9 months 22 days
Vested and exercisable, aggregate intrinsic value	$ 424,203

Employee Incentive Plans - Sc52

Employee Incentive Plans - Schedule of Black-Scholes Option Pricing Model Estimated Fair Value Assumptions (Details)	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility rate	0.00%	0.00%	40.00%
Expected volatility, minimum				40.00%
Expected volatility, maximum				41.00%
Expected term (in years)	0 years	0 years	6 years 3 months
Risk-free interest rate	0.00%	0.00%	2.70%
Risk-free interest rate, minimum				2.06%
Risk-free interest rate, maximum				2.21%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Stock options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)				6 years
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)				6 years 4 months 24 days
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	39.00%	32.00%	39.00%	32.00%
Expected volatility, maximum	40.00%	34.00%	40.00%	37.00%
Risk-free interest rate, minimum	2.12%	1.12%	2.12%	0.95%
Risk-free interest rate, maximum	2.34%	1.22%	2.34%	1.22%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
ESPP | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months	6 months	6 months
ESPP | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	1 year	1 year	1 year	1 year 2 months 12 days

Employee Incentive Plans - Sc53

Employee Incentive Plans - Schedule of Restricted Stock Unit Activity (Details) - Restricted stock units	6 Months Ended
	Jul. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares) | shares	2,862,929
Granted during period (in shares) | shares	2,752,588
Vested during period (in shares) | shares	(542,969)
Forfeited during period (in shares) | shares	(181,762)
Ending balance (in shares) | shares	4,890,786
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance (in dollars per share) | $ / shares	$ 24.38
Granted during period (in dollars per share) | $ / shares	50.67
Vested during period (in dollars per share) | $ / shares	22.71
Forfeited during period (in dollars per share) | $ / shares	29.39
Ending balance (in dollars per share) | $ / shares	$ 39.17

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended			12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017		Jul. 31, 2018	Jul. 31, 2017		Jan. 31, 2018
Income Tax Disclosure [Abstract]
Tax (benefit) provision	$ (985)	$ 229	[1]	$ (1,216)	$ 477	[1]
Loss before income taxes	$ 40,192	$ 25,803	[1]	$ 66,385	$ 53,261	[1]
Effective income tax rate	2.50%	(0.90%)		1.80%	(0.90%)
Deferred tax asset as a result of deductible temporary difference	$ 600			$ 600
Reduction in deferred tax asset before valuation allowance due to change in tax rate							$ 61,000
[1]	See Note 2 for a summary of adjustments.

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017		Jul. 31, 2018	Jul. 31, 2017
Numerator:
Net loss	$ (39,207)	$ (26,032)	[1],[2]	$ (65,169)	$ (53,738)	[1],[3]
Denominator:
Weighted-average shares outstanding - basic and diluted (in shares)	106,702	93,576	[1]	105,475	67,125	[1]
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.37)	$ (0.28)	[1]	$ (0.62)	$ (0.80)	[1]
Class A Common Stock
Numerator:
Net loss	$ (33,862)	$ (4,075)		$ (53,242)	$ (7,254)
Denominator:
Weighted-average shares outstanding - basic and diluted (in shares)	92,156	14,650		86,172	9,061
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.37)	$ (0.28)		$ (0.62)	$ (0.80)
Class B Common Stock
Numerator:
Net loss	$ (5,345)	$ (21,957)		$ (11,927)	$ (46,484)
Denominator:
Weighted-average shares outstanding - basic and diluted (in shares)	14,546	78,926		19,303	58,064
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.37)	$ (0.28)		$ (0.62)	$ (0.80)
[1]	See Note 2 for a summary of adjustments.
[2]	See Note 2 for a summary of adjustments.
[3]	See Note 2 for a summary of adjustments.

Net Loss Per Share - Schedule56

Net Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Per Share (Details) - shares shares in Thousands	6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	34,167	38,375
Unvested restricted common stock issued and outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	400	800
Stock options issued and outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	20,898	33,360
Unvested RSUs issued and outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	4,891	2,210
Unvested restricted stock awards issued and outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	388	599
Shares related to convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	7,134	0
Shares committed under the ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	360	1,082
Unvested shares subject to repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	96	324

Net Loss Per Share - Narrative

Net Loss Per Share - Narrative (Details)	Feb. 23, 2018$ / shares
Convertible Senior Notes Due 2023 | Senior Notes
Debt Instrument [Line Items]
Conversion price (in dollars per share)	$ 48.36