Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Oct. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and accounts have been eliminated. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the applicable rules and regulations of the Securities and Exchange Commission (“SEC”). Therefore, these unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related footnotes included in the Company’s final prospectus for its IPO dated as of October 18, 2017 and filed with the SEC pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended, on October 19, 2017.
Use of Estimates	The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Such estimates include, but are not limited to, revenue recognition, allowances for doubtful accounts, stock-based compensation, fair value of common stock and redeemable convertible preferred stock warrants prior to the IPO, legal contingencies, fair value of acquired intangible assets and goodwill, useful lives of acquired intangible assets and property and equipment, and accounting for income taxes. The Company bases these estimates on historical and anticipated results, trends and various other assumptions that it believes are reasonable under the circumstances, including assumptions as to future events. Actual results could differ from those estimates.
Emerging Growth Company Status	As an “emerging growth company” (“EGC”), the Jump-start Our Business Start-ups Act (“JOBS Act”), allows the Company to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. The Company has elected to use this extended transition period under the JOBS Act. As a result, the Company’s financial statements may not be comparable to the financial statements of issuers who are required to comply with the effective dates for new or revised accounting standards that are applicable to public companies, which may make the Company’s common stock less attractive to investors.
Recently Adopted and Not Yet Adopted New Accounting Pronouncements	Recently Adopted Accounting Pronouncements Stock-Based Compensation. Starting February 1, 2016, the Company elected to early adopt Accounting Standards Update (“ASU”) No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvement to Employee Share-based Payment Accounting, which would among other items, provide an accounting policy election to account for forfeitures as they occur, rather than to account for them based on an estimate of expected forfeitures and modifies financial statement presentation of excess tax benefits or deficiencies. The Company elected to account for forfeitures as they occur and therefore, stock-based compensation expense for the three and nine months ended October 31, 2017 and 2016 has been calculated based on actual forfeitures in the unaudited condensed consolidated statements of operations. The cumulative effect of this change increased the accumulated deficit and decreased additional paid-in capital as of February 1, 2016 by $1.5 million. In addition, the effect on the Company’s historical consolidated financial statements was limited to an immaterial cumulative-effect adjustment for previously unrecognized excess tax benefits as a deferred tax asset with an offset to opening accumulated deficit, which was fully offset by a valuation allowance. Consolidated Statements of Cash Flows. Starting February 1, 2016, the Company elected to early adopt ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments and ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. ASU No. 2016-15 eliminates the diversity in practice related to the classification of certain cash receipts and payments for debt prepayment or extinguishment costs, the maturing of a zero-coupon bond, the settlement of contingent liabilities arising from a business combination, proceeds from insurance settlements, distributions from certain equity method investees and beneficial interests obtained in a financial asset securitization. ASU No. 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The Company adopted ASU No. 2016-15 and ASU No. 2016-18 using the retrospective transition method and adjusted the consolidated statements of cash flows in all comparative periods presented. New Accounting Pronouncements Not Yet Adopted Stock-Based Compensation. In May 2017, the Financial Accounting Standards Board (“FASB”), issued ASU 2017-09, Compensation—Stock Compensation (Topic 718). The amendments in the update provide guidance on types of changes to the terms or conditions of share-based payment awards, which would be required to apply modification accounting under Accounting Standards Codification (“ASC”) 718. The new guidance becomes effective for the Company for the fiscal year ending January 31, 2018, though early adoption is permitted. The Company is currently evaluating whether this standard will have a material impact on its consolidated financial statements. Goodwill Impairment. In January 2017, the FASB issued ASU 2017-04—Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The new standard will simplify the measurement of goodwill by eliminating step two of the two-step impairment test. Step two measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. The new guidance requires an entity to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The new guidance becomes effective for the Company for the fiscal year ending January 31, 2022, though early adoption is permitted. The Company does not expect the adoption of the new accounting standard to have a material impact on its consolidated financial statements. Leases. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which modifies lease accounting for lessees to increase transparency and comparability by recording lease assets and liabilities for operating leases and disclosing key information about leasing arrangements. Depending on when the Company loses its EGC status, it may be required to adopt the new lease standard as early as its interim results for the period ending April 30, 2019, but no later than for its annual results for the fiscal year ending January 31, 2021, though early adoption is permitted. The Company is currently evaluating adoption methods and whether this standard will have a material impact on its consolidated financial statements. Revenue Recognition. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which amends the existing accounting standard for revenue recognition. ASU 2014-09 is based on principles that govern the recognition of revenue at an amount to which an entity expects to be entitled when products are transferred to customers. Subsequently, the FASB has issued the following pronouncements related to ASU 2014-09: ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations; ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing; ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients; and ASU 2016-20, Technical Corrections and Improvements to Topic 606, which clarifies narrow aspects of ASC 606 or corrects unintended application of the guidance. The Company must adopt ASU 2016-08, ASU 2016-10, ASU 2016-12, and ASU 2016-20 with ASU 2014-09 (collectively, the “new revenue standard”).
Equity Incentive Plans	The determination of the fair value of stock options on the date of grant using an option-pricing model is affected by the fair value of the Company’s common stock, as well as assumptions regarding a number of complex and subjective variables. The Company uses the Black-Scholes option-pricing model to calculate the fair value of stock options, , which requires the use of assumptions including actual and projected employee stock option exercise behaviors, expected price volatility of the Company’s common stock, the risk-free interest rate and expected dividends. Each of these inputs is subjective and generally requires significant judgment to determine. Fair Value of Common Stock. Prior to the IPO, the fair value of common stock underlying the stock options had historically been determined by the Board of Directors, with input from the Company’s management. The Board of Directors previously determined the fair value of the common stock at the time of grant of the options by considering a number of objective and subjective factors, including valuations of comparable companies, sales of redeemable convertible preferred stock, sales of common stock to unrelated third parties, operating and financial performance, the lack of liquidity of the Company’s capital stock, and general and industry-specific economic outlook. Subsequent to the IPO, the fair value of the underlying common stock is determined by the closing price, on the date of grant, of the Company’s Class A common stock, which is traded publicly on the NASDAQ Stock Market. Expected Term. The expected term represents the period that stock-based awards are expected to be outstanding. For option grants that are considered to be “plain vanilla,” the Company determines the expected term using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the options. For other option grants, the Company estimates the expected term using historical data on employee exercises and post-vesting employment termination behavior taking into account the contractual life of the award. Expected Volatility. Since the Company has limited trading history of its common stock, the expected volatility is derived from the average historical stock volatilities of several unrelated public companies within the Company’s industry that the Company considers to be comparable to its own business over a period equivalent to the expected term of the stock option grants. Risk-Free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the option’s expected term. Dividend Rate. The expected dividend is assumed to be zero as the Company has never paid dividends and has no current plans to do so.
Net Loss per Share	The Company calculates basic and diluted net loss per share attributable to common stockholders in conformity with the two-class method required for companies with participating securities. The Company considered all series of redeemable convertible preferred stock to have been participating securities as the holders were entitled to receive non-cumulative dividends on a pari passu basis in the event that a dividend was paid on common stock. Under the two-class method, the net loss attributable to common stockholders is not allocated to the redeemable convertible preferred stock as the holders of redeemable convertible preferred stock do not have a contractual obligation to share in losses. Under the two-class method, basic net loss per share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, less shares subject to repurchase. Diluted net loss per share attributable to common stockholders is computed by giving effect to all potentially dilutive common stock equivalents outstanding for the period. For purposes of this calculation, redeemable convertible preferred stock, stock options to purchase common stock, early exercised stock options, and warrants to purchase redeemable convertible preferred stock and common stock are considered common shares equivalents, but have been excluded from the calculation of diluted net loss per share attributable to common stockholders as their effect is antidilutive.
Income Taxes	The Company assesses uncertain tax positions in accordance with ASC 740-10, Accounting for Uncertainties in Tax.

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.