Mimecast (MIME) 10-Q 8 Nov 18 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,019
Document Fiscal Period Focus	Q2
Trading Symbol	MIME
Entity Registrant Name	Mimecast Ltd
Entity Central Index Key	1,644,675
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		60,063,419

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Current assets
Cash and cash equivalents	$ 118,881	$ 78,339
Short-term investments	25,491	58,871
Accounts receivable, net	59,966	65,392
Deferred contract costs, net	6,265
Prepaid expenses and other current assets	12,282	15,302
Total current assets	222,885	217,904
Property and equipment, net	131,608	123,822
Intangible assets, net	29,521	9,819
Goodwill	103,062	5,631
Deferred contract costs, net of current portion	21,319
Other assets	2,393	1,222
Total assets	510,788	358,398
Current liabilities
Accounts payable	7,236	6,052
Accrued expenses and other current liabilities	37,553	33,878
Deferred revenue	124,894	123,057
Current portion of capital lease obligations	1,164	1,125
Current portion of long-term debt	2,814
Total current liabilities	173,661	164,112
Deferred revenue, net of current portion	11,722	18,045
Long-term capital lease obligations	1,892	2,390
Long-term debt	95,154
Construction financing lease obligations	76,269	67,205
Other non-current liabilities	7,342	4,954
Total liabilities	366,040	256,706
Commitments and contingencies (Note 15)
Shareholders' equity
Ordinary shares, $0.012 par value, 300,000,000 shares authorized; 60,042,667 and 58,949,644 shares issued and outstanding as of September 30, 2018 and March 31, 2018, respectively	721	707
Additional paid-in capital	233,302	212,839
Accumulated deficit	(82,160)	(106,507)
Accumulated other comprehensive loss	(7,115)	(5,347)
Total shareholders' equity	144,748	101,692
Total liabilities and shareholders' equity	$ 510,788	$ 358,398

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Mar. 31, 2018
Statement Of Financial Position [Abstract]
Ordinary shares, par value	$ 0.012	$ 0.012
Ordinary shares, authorized	300,000,000	300,000,000
Ordinary shares, issued	60,042,667	58,949,644
Ordinary shares, outstanding	60,042,667	58,949,644

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 82,169	$ 63,066	$ 160,573	$ 121,224
Cost of revenue	21,938	16,543	42,914	31,795
Gross profit	60,231	46,523	117,659	89,429
Operating expenses
Research and development	14,157	8,262	27,257	16,183
Sales and marketing	34,705	30,155	68,908	57,714
General and administrative	12,448	8,614	24,662	17,151
Restructuring	(170)		(170)
Total operating expenses	61,140	47,031	120,657	91,048
Loss from operations	(909)	(508)	(2,998)	(1,619)
Other income (expense)
Interest income	543	314	987	553
Interest expense	(1,568)	(69)	(2,095)	(100)
Foreign exchange expense and other, net	498	(655)	57	(1,195)
Total other income (expense), net	(527)	(410)	(1,051)	(742)
Loss before income taxes	(1,436)	(918)	(4,049)	(2,361)
Provision for income taxes	622	421	1,480	878
Net loss	$ (2,058)	$ (1,339)	$ (5,529)	$ (3,239)
Net loss per ordinary share
Basic and diluted	$ (0.03)	$ (0.02)	$ (0.09)	$ (0.06)
Weighted-average number of ordinary shares outstanding:
Basic and diluted	59,800	57,027	59,489	56,662

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (2,058)	$ (1,339)	$ (5,529)	$ (3,239)
Other comprehensive income (loss):
Net unrealized gains (losses) on investments, net of tax	32	9	96	(57)
Change in foreign currency translation adjustment	305	(596)	(1,862)	(364)
Reclassification of cumulative translation adjustment to net loss upon liquidation of subsidiaries, net of tax				188
Total other comprehensive income (loss)	337	(587)	(1,766)	(233)
Comprehensive loss	$ (1,721)	$ (1,926)	$ (7,295)	$ (3,472)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net loss	$ (5,529)	$ (3,239)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	14,280	7,859
Share-based compensation expense	11,290	5,556
Amortization of deferred contract costs	2,879
Amortization of debt issuance costs	123	5
Other non-cash items	(372)	159
Unrealized currency (gain) loss on foreign denominated transactions	(499)	798
Changes in assets and liabilities:
Accounts receivable	2,457	(319)
Prepaid expenses and other current assets	3,282	(1,774)
Deferred contract costs	(7,771)
Other assets	(1,208)	33
Accounts payable	2,971	1,493
Deferred revenue	6,646	7,445
Accrued expenses and other liabilities	554	956
Net cash provided by operating activities	29,103	18,972
Investing activities
Purchases of investments	(6,984)	(24,521)
Maturities of investments	40,500	38,500
Purchases of property, equipment and capitalized software	(15,843)	(13,403)
Payments for acquisitions, net of cash acquired	(108,913)
Net cash (used in) provided by investing activities	(91,240)	576
Financing activities
Proceeds from issuance of ordinary shares	9,211	6,436
Payments on debt	(625)	(1,078)
Payments on capital lease obligations	(442)	(189)
Payments on construction financing lease obligations	(840)
Proceeds from issuance of debt, net of issuance costs	97,748
Net cash provided by financing activities	105,052	5,169
Effect of foreign exchange rates on cash	(2,373)	892
Net increase in cash and cash equivalents	40,542	25,609
Cash and cash equivalents at beginning of period	78,339	51,319
Cash and cash equivalents at end of period	118,881	76,928
Supplemental disclosure of cash flow information
Cash paid during the period for interest	1,354	81
Cash paid during the period for income taxes	1,034	1,440
Supplemental disclosure of non-cash investing and financing activities
Unpaid purchases of property, equipment and capitalized software	4,157	4,592
Property and equipment acquired under capital lease		3,834
Construction costs capitalized under financing lease obligations	$ 10,296	$ 26,110

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Mimecast Limited (Mimecast Jersey) is a public limited company organized under the laws of the Bailiwick of Jersey on July 28, 2015. On November 4, 2015, Mimecast Jersey changed its corporate structure whereby it became the holding company of Mimecast Limited (Mimecast UK), a private limited company incorporated in 2003 under the laws of England and Wales, and its wholly-owned subsidiaries by way of a share-for-share exchange in which the shareholders of Mimecast UK exchanged their shares in Mimecast UK for an identical number of shares of the same class in Mimecast Jersey. Upon the exchange, the historical consolidated financial statements of Mimecast UK became the historical consolidated financial statements of Mimecast Jersey. Mimecast Jersey and its subsidiaries (together the Group, the Company, Mimecast or we) is headquartered in London, England. The principal activity of the Group is the provision of email management services. Mimecast delivers a software-as-a-service (SaaS) enterprise email management service for archiving, continuity, and security, web security and awareness training. By unifying disparate and fragmented email environments into one holistic solution from the cloud, Mimecast minimizes risk and reduces cost and complexity while providing total end-to-end control of email. Mimecast’s proprietary software platform provides a single system to address key email management issues. Mimecast operates principally in Europe, North America, Africa, and Australia. The Company is subject to a number of risks and uncertainties common to companies in similar industries and stages of development including, but not limited to, rapid technological changes, competition from substitute products and services from larger companies, customer concentration, management of international activities, protection of proprietary rights, patent litigation, and dependence on key individuals. Basis of Presentation The accompanying interim condensed consolidated financial statements are unaudited. These financial statements and notes should be read in conjunction with the audited consolidated financial statements for the year ended March 31, 2018 and related notes, together with management’s discussion and analysis of financial condition and results of operations, contained in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on May 29, 2018. The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States (GAAP) have been condensed or omitted. In the opinion of management, the unaudited condensed consolidated financial statements and notes have been prepared on the same basis as the audited consolidated financial statements for the year ended March 31, 2018 contained in the Company’s Annual Report on Form 10-K and include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the Company’s financial position as of September 30, 2018, and for the three and six months ended September 30, 2018 and 2017. These interim periods are not necessarily indicative of the results to be expected for any other interim period or the full year. The Company reclassified $0.1 million of provision for doubtful accounts to accounts receivable within its condensed consolidated statements of cash flows for the six months ended September 30, 2017 in this quarterly report on Form 10-Q to conform to current period presentation. This had no impact on the Company’s previously reported results of operations or its balance sheets. The accompanying condensed consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the condensed consolidated financial statements. As of September 30, 2018, the Company’s significant accounting policies and estimates, which are detailed in the Company’s Annual Report on Form 10-K, have not changed, except as discussed below. Revenue Recognition Adoption of ASC 606 Effective April 1, 2018, the Company adopted the requirements of Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers: Topic 606 Revenue Recognition Revenue Recognition Policy Under ASC 606 the Company recognizes revenue upon transfer of control of promised products or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. To achieve the core principle of ASC 606, the Company performs the following steps: 1) Identify the contract(s) with a customer; 2) Identify the performance obligations in the contract; 3) Determine the transaction price; 4) Allocate the transaction price to the performance obligations in the contract; and 5) Recognize revenue when (or as) we satisfy a performance obligation. The Company derives its revenue from two sources: (1) subscription revenues, which are comprised of subscription fees from customers accessing the Company’s cloud services and from customers purchasing additional support beyond the standard support that is included in the basic subscription fees; and (2) related professional services and other revenue, which consists primarily of certain performance obligations related to set-up, ingestion, consulting and training fees. In the three and six months ended September 30, 2018 and 2017, subscription revenue made up the substantial majority of the Company’s revenue and professional services and other revenue made up less than 5% of the Company’s revenue. The Company’s subscription arrangements provide customers the right to access the Company’s hosted software applications. Customers do not have the right to take possession of the Company’s software during the hosting arrangement. The Company sells its products and services directly through the Company’s sales force and also indirectly through third-party resellers. In accordance with the provisions of ASC 606, the Company has considered certain factors in determining whether the end-user or the third-party reseller is the customer in arrangements involving resellers. The Company concluded that in the majority of transactions with resellers, the reseller is the customer. In these arrangements, the Company considered that it is the reseller, and not the Company, that has the relationship with the end-user. Specifically, the reseller has the ability to set pricing with the end-user and the credit risk with the end-user is borne by the reseller. Further, the reseller is not obligated to report its transaction price with the end-user to the Company, and in the majority of transactions, the Company is unable to determine the amount paid by the end-user customer to the reseller in these transactions. As a result of such considerations, revenue for these transactions is presented in the accompanying condensed consolidated statements of operations based upon the amount billed to the reseller. For transactions where we have determined that the end-user is the ultimate customer, revenue is presented in the accompanying condensed consolidated statements of operations based on the transaction price with the end-user. The Company recognizes subscription and support revenue ratably over the term of the contract, typically one year in duration, beginning on the date the customer is provided access to the Company’s service. For performance obligations related to set-up and ingestion, including implementation assistance and data migration services, respectively, the Company recognizes revenue using output measures of performance that reflect the transfer of promised services to the customer consistent with progress to completion. The Company recognizes revenue on training, consulting, and other professional services contracts using output measures of performance as services are completed. Training, consulting, and other professional services are considered separate performance obligations. Amounts that have been invoiced are recorded in accounts receivable and in deferred revenue or revenue, depending on whether the revenue recognition criteria have been met. The Company primarily bills and collects payments from customers for its services in advance on a monthly and annual basis. In some instances, the Company receives non-refundable upfront payments for activities that do not constitute a promise to transfer a service and therefore are considered administrative tasks, not separate performance obligations. The upfront payments are evaluated to determine whether a material right to a discount upon renewal of the subscription exists. When the Company concludes a material right does not exist, the Company recognizes revenue related to the upfront payment over the initial contract term. When the Company concludes a material right does exist, the Company recognizes revenue related to the upfront payment, under the look-through method, over the estimated customer benefit period, which has been determined to be six years. All of the Company’s performance obligations, and associated revenue, are generally transferred to customers over time, with the exception of training, consulting and other professional services, which are generally transferred to the customer at a point in time. Revenue is presented net of any taxes collected from customers. 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 standalone selling price basis. The Company determines the standalone selling prices based on the Company’s overall pricing objectives, taking into consideration market conditions and other factors, including the value of the Company’s contracts, the products sold, customer demographics, the Company’s sales channel, and the number and size of users within the Company’s contracts. Deferred revenue primarily consists of billings or payments received in advance of revenue recognition from subscription and other services described above and is recognized as the revenue recognition criteria are met. Deferred revenue that is expected to be recognized during the succeeding twelve-month period is recorded as current deferred revenue and the remaining portion is recorded as non-current in the accompanying condensed Deferred Cost Policy As part of the Company’s adoption of ASC 606 , the Company capitalizes incremental costs of obtaining revenue contracts, which primarily consist of commissions paid to its sales representatives. The Company amortizes these commissions over six years on a systematic basis, consistent with the pattern of transfer of the goods or services to which the asset relates. Six years represents the estimated benefit period of the customer relationship taking into account factors such as peer estimates of technology lives and customer lives as well as the Company's own historical data. No commissions are paid related to contract renewals. The current and noncurrent portions of deferred commissions are included in deferred contract costs, net, and deferred contract costs, net of current portion, respectively, in the accompanying condensed consolidated balance sheets. Impact of Adoption of ASC 606 The adoption of ASC 606 resulted in a decrease to deferred revenue of $6.0 million and an increase of $23.8 million in deferred contract costs as of April 1, 2018. The Company recorded the deferred tax impact associated with the cumulative-effect adjustment of adopting ASC 606 to accumulated deficit with an equal and offsetting adjustment to the Company’s valuation allowance. The decrease to deferred revenue upon adoption was primarily due to a change in the accounting treatment for certain upfront fees that were accounted for as a single unit of account under Legacy GAAP and are accounted for as separate performance obligations under ASC 606. The increase in deferred contract costs was the result of the capitalization of certain commissions that were determined to be incremental costs of obtaining a contract. Under Legacy GAAP, the Company expensed all commission costs as incurred. As a result of the adoption of ASC 606, the Company’s accumulated deficit decreased by $29.9 million as of April 1, 2018, which was the net cumulative impact associated with the capitalization of sales commissions and the adjustment to deferred revenue. The cumulative effect of the changes made to the Company’s April 1, 2018 balance sheet for the adoption of ASC 606 were as follows: Balance as of March 31, 2018 Adjustments Due to Adoption of ASC 606 Balance as of April 1, 2018 Assets Deferred contract costs, net $ — $ 5,494 $ 5,494 Deferred contract costs, net of current portion — 18,339 18,339 Liabilities Deferred revenue 123,057 (517 ) 122,540 Deferred revenue, net of current portion 18,045 (5,526 ) 12,519 Shareholders' equity Accumulated deficit (106,507 ) 29,876 (76,631 ) In accordance with the requirements of ASC 606, the disclosure for the quantitative effect and the significant changes between the reported results under ASC 606 and those that would have been reported under Legacy GAAP on our unaudited condensed Three months ended September 30, 2018 As Reported - ASC 606 Amounts without Adoption of ASC 606 Effect of Change Increase/(Decrease) Income Statement Revenues $ 82,169 $ 81,447 $ 722 Operating expenses Sales and marketing (34,705 ) (37,330 ) (2,625 ) Net loss $ (2,058 ) $ (5,405 ) $ 3,347 Six months ended September 30, 2018 As Reported - ASC 606 Amounts without Adoption of ASC 606 Effect of Change Increase/(Decrease) Income Statement Revenues $ 160,573 $ 159,555 $ 1,018 Operating expenses Sales and marketing (68,908 ) (73,797 ) (4,889 ) Net loss $ (5,529 ) $ (11,436 ) $ 5,907 As of September 30, 2018 As Reported - ASC 606 Balances without Adoption of ASC 606 Effect of Change Increase/(Decrease) Balance Sheet Assets Deferred contract costs, net $ 6,265 $ — $ 6,265 Deferred contract costs, net of current portion 21,319 — 21,319 Liabilities Deferred revenue 124,894 124,758 136 Deferred revenue, net of current portion 11,722 18,688 (6,966 ) Shareholders' equity Accumulated deficit (82,160 ) (117,943 ) 35,783 Revenue recognized during the three and six months ended September 30, 2018 from amounts included in deferred revenue at the beginning of the period was approximately $53.4 million and $84.5 million, respectively. Revenue recognized during the three and six months ended September 30, 2018 from performance obligations satisfied or partially satisfied in previous periods was not material. The adoption of ASC 606 had no impact to net operating cash flows. Contracted revenue as of September 30, 2018 that has not yet been recognized (“contracted not recognized”) was $74.0 million, which includes deferred revenue and non-cancellable amounts that will be invoiced and recognized as revenue in future periods and excludes contracts with an original expected length of one year or less. The Company expects 51% of contracted and not recognized revenue to be recognized over the next twelve months, 45% in years two and three, with the remaining balance recognized thereafter.

Principles of Consolidation

Principles of Consolidation	6 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Principles of Consolidation	2. Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates

Use of Estimates	6 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Use of Estimates	3. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of income and expenses during the reporting period. Significant estimates relied upon in preparing these condensed consolidated financial statements include revenue recognition, variable consideration, valuation at fair value of assets acquired or sold, including intangibles, goodwill, tangible assets, and liabilities assumed, amortization periods, expected future cash flows used to evaluate the recoverability of long-lived assets, contingent liabilities, construction financing lease obligations, restructuring liabilities, expensing and capitalization of research and development costs for internal-use software, the determination of the fair value of share-based awards issued, the average period of benefit associated with costs capitalized to obtain revenue contracts and the recoverability of the Company’s net deferred tax assets and related valuation allowance. Although the Company regularly assesses these estimates, actual results could differ materially from these estimates. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results may differ from management’s estimates if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. Changes in estimates are recorded in the period in which they become known.

Subsequent Events Consideration

Subsequent Events Considerations	6 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events Considerations	4. Subsequent Events Considerations The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure.

Concentration of Credit Risk an

Concentration of Credit Risk and Off-Balance Sheet Risk	6 Months Ended
	Sep. 30, 2018
Risks And Uncertainties [Abstract]
Concentration of Credit Risk and Off-Balance Sheet Risk	5. Concentration of Credit Risk and Off-Balance Sheet Risk The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments, which potentially subject the Company to concentrations of credit risk, consist primarily of cash and cash equivalents, investments and accounts receivable. The Company maintains its cash, cash equivalents and investments with major financial institutions of high-credit quality. Although the Company deposits its cash with multiple financial institutions, its deposits, at times, may exceed federally insured limits. Credit risk with respect to accounts receivable is dispersed due to our large number of customers. The Company’s accounts receivable are derived from revenue earned from customers primarily located in the United States, the United Kingdom and South Africa. The Company generally does not require its customers to provide collateral or other security to support accounts receivable. Credit losses historically have not been significant and the Company generally has not experienced any material losses related to receivables from individual customers, or groups of customers. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company’s accounts receivable. As of September 30, 2018 and March 31, 2018, no individual customer represented more than 10% of the Company’s accounts receivable. During the three and six months ended September 30, 2018 and 2017, no individual customer represented more than 10% of the Company’s revenue. As of September 30, 2018, the Company’s investments consisted primarily of investment-grade fixed income corporate debt securities with maturities ranging from less than one month to five months and non-U.S. government securities with maturities in approximately one month. We diversify our investment portfolio by investing in multiple types of investment-grade securities and attempt to mitigate a risk of loss by using a third-party investment manager.

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments	6 Months Ended
	Sep. 30, 2018
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents and Investments	6. Cash, Cash Equivalents and Investments The Company considers all highly liquid instruments purchased with an original maturity date of 90 days or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist of cash on deposit with banks, amounts held in interest-bearing money market funds and investments with maturities of 90 days or less from the date of purchase. Cash equivalents are carried at cost, which approximates their fair market value. Investments not classified as cash equivalents are presented as either short-term or long-term investments based on both their stated maturities as well as the time period the Company intends to hold such securities. The Company determines the appropriate classification of investments at the time of purchase and reevaluates such designation at each balance sheet date. The Company adjusts the cost of investments for amortization of premiums and accretion of discounts to maturity. The Company includes such amortization and accretion in interest income. The Company has classified all of its investments as of September 30, 2018, as available-for-sale pursuant to Accounting Standard Codification (ASC) 320, Investments – Debt and Equity Securities The Company reviews investments for other-than-temporary impairment whenever the fair value of an investment is less than its amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the condensed consolidated statements of operations if the Company has experienced a credit loss, has the intent to sell the investment, or if it is more likely than not that the Company will be required to sell the investment before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period. As of September 30, 2018, the aggregate fair value of investments held by the Company in an unrealized loss position for less than twelve months was $13.5 million. As of September 30, 2018, the Company determined that no other-than-temporary impairments were required to be recognized in the condensed consolidated statements of operations. The following is a summary of cash, cash equivalents and investments as of September 30, 2018 and March 31, 2018: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value September 30, 2018: Cash and cash equivalents due in 90 days or less $ 118,881 $ — $ — $ 118,881 Investments: Non-U.S. government securities due in one year or less 2,996 15 — 3,011 Corporate securities due in one year or less 22,488 18 (26 ) 22,480 Total investments 25,484 33 (26 ) 25,491 Total cash, cash equivalents and investments $ 144,365 $ 33 $ (26 ) $ 144,372 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value March 31, 2018: Cash and cash equivalents due in 90 days or less $ 78,339 $ — $ — $ 78,339 Investments: U.S. treasury securities due in one year or less 2,995 — (5 ) 2,990 Non-U.S. government securities due in one year or less 5,996 1 (1 ) 5,996 Corporate securities due in one year or less 49,969 8 (92 ) 49,885 Total investments 58,960 9 (98 ) 58,871 Total cash, cash equivalents and investments $ 137,299 $ 9 $ (98 ) $ 137,210

Disclosure of Fair Value of Fin

Disclosure of Fair Value of Financial Instruments	6 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Disclosure of Fair Value of Financial Instruments	7. Disclosure of Fair Value of Financial Instruments The Company’s financial instruments include cash, cash equivalents, accounts receivable, investments, accounts payable, accrued expenses and borrowings under the Company’s long-term debt arrangements. The carrying amount of the Company’s long-term debt arrangements approximates its fair values due to the interest rates the Company believes it could obtain for borrowings with similar terms. The Company’s investments are classified as available-for-sale and reported at fair value in accordance with the market approach utilizing quoted prices that were directly or indirectly observable. The carrying amount of the remainder of the Company’s financial instruments approximated their fair values as of September 30, 2018 and March 31, 2018, due to the short-term nature of those instruments. The Company has evaluated the estimated fair value of financial instruments using available market information. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. Fair values determined using “Level 1 inputs” utilize unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access. Fair values determined using “Level 2 Inputs” utilize quoted prices that are directly or indirectly observable. Fair values determined using “Level 3 inputs” utilize unobservable inputs for determining fair values of assets or liabilities that reflect an entity's own assumptions in pricing assets or liabilities. As of September 30, 2018 and March 31, 2018, the Company did not have any assets or liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). The Company measures eligible assets and liabilities at fair value, with changes in value recognized in earnings. Fair value treatment may be elected either upon initial recognition of an eligible asset or liability or, for an existing asset or liability, if an event triggers a new basis of accounting. The Company did not elect to remeasure any of its existing financial assets or liabilities, and did not elect the fair value option for any financial assets and liabilities transacted in the three and six months ended September 30, 2018 and 2017. The following table summarizes financial assets measured and recorded at fair value on a recurring basis in the accompanying condensed consolidated balance sheets as of September 30, 2018 and March 31, 2018, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: September 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1 Inputs) Significant Other Observable Inputs (Level 2 Inputs) Total Assets: Money market funds $ 7,785 $ — $ 7,785 Non-U.S. government securities — 3,011 3,011 Corporate securities — 22,480 22,480 Total assets $ 7,785 $ 25,491 $ 33,276 March 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1 Inputs) Significant Other Observable Inputs (Level 2 Inputs) Total Assets: Money market funds $ 10,143 $ — $ 10,143 U.S. treasury securities — 2,990 2,990 Non-U.S. government securities — 5,996 5,996 Corporate securities — 49,885 49,885 Total assets $ 10,143 $ 58,871 $ 69,014

Internal-use Software Costs

Internal-use Software Costs	6 Months Ended
	Sep. 30, 2018
Research And Development [Abstract]
Internal-use Software Costs	8. Internal-use Software Costs Software Development Costs Costs incurred to develop software applications used in the Company’s SaaS platform consist of certain direct costs of materials and services incurred in developing or obtaining internal-use computer software, and payroll and payroll-related costs for employees who are directly associated with, and who devote time to, the project. These costs generally consist of internal labor during configuration, coding, and testing activities. Research and development costs incurred during the preliminary project stage or costs incurred for data conversion activities, training, maintenance and general and administrative or overhead costs are expensed as incurred. Once an application has reached the development stage, internal and external costs, if direct and incremental, are capitalized until the application is substantially complete and ready for its intended use. Qualified costs incurred during the operating stage of the Company’s software applications relating to upgrades and enhancements are capitalized to the extent it is probable that they will result in added functionality, while costs incurred for maintenance of, and minor upgrades and enhancements to, internal-use software are expensed as incurred. During the three and six months ended September 30, 2018 and 2017, the Company believes the substantial majority of its development efforts were either in the preliminary project stage of development or in the operation stage (post-implementation), and accordingly, no costs have been capitalized during these periods. These costs are included in the accompanying condensed consolidated statements of operations as research and development expense. Cloud-computing Arrangements The Company evaluates its accounting for fees paid in cloud computing arrangements (CCA) including determining whether the CCA includes a license to internal-use software. If the CCA includes a software license, the Company accounts for the software license as an intangible asset. Acquired software licenses are recognized and measured at cost, which includes the present value of the license obligation if the license is to be paid for over time. If the CCA does not include a software license, the Company accounts for the arrangement as a service contract (hosting arrangement) and hosting costs are generally expensed as incurred. Upon adoption of ASU 2018-15, the Company evaluates upfront costs including implementation, set-up or other costs (collectively, implementation costs) for hosting arrangements under the internal-use software framework. Costs related to preliminary project activities and post implementation activities are expensed as incurred, whereas costs incurred in the development stage are generally capitalized. Capitalized implementation costs are amortized on a straight-line basis over the expected term of the hosting arrangement, which includes consideration of the noncancellable contractual term and reasonably certain renewals. During the three and six months ended September 30, 2018, the Company capitalized $0.9 million of implementation costs related to hosting arrangements that were incurred during the application development stage. These capitalized implementation costs will be amortized over the expected term of the arrangement determined to be four years through sales and marketing expense within the condensed consolidated statements of operations.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net Loss Per Share The Company calculates basic and diluted net loss per ordinary share by dividing net loss by the weighted-average number of ordinary shares outstanding during the period. The Company has excluded other potentially dilutive shares, which include outstanding options to purchase ordinary shares and unvested restricted share units, from the weighted-average number of ordinary shares outstanding as their inclusion in the computation for all periods would be anti-dilutive due to net losses incurred. The following potentially dilutive ordinary share equivalents have been excluded from the calculation of diluted weighted-average shares outstanding as their effect would have been anti-dilutive for the periods presented (in thousands): Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Share options outstanding 7,164 7,425 7,164 7,425 Unvested restricted share units 419 44 419 44 ESPP shares 64 70 64 70

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	10. Share-Based Compensation As of September 30, 2018, the Company has four share-based compensation plans and an employee share purchase plan. Prior to the Company’s initial public offering (IPO) in November 2015, the Company granted share-based awards under three share option plans, which were the Mimecast Limited 2007 Key Employee Share Option Plan (the 2007 Plan), the Mimecast Limited 2010 EMI Share Option Scheme (the 2010 Plan), and the Mimecast Limited Approved Share Option Plan (the Approved Plan) (the 2007 Plan, the 2010 Plan and the Approved Plan, collectively, the Historical Plans). Upon the closing of the IPO, the Mimecast Limited 2015 Share Option and Incentive Plan (the 2015 Plan) and the 2015 Employee Share Purchase Plan (the ESPP) became effective. Share Options The fair value of each share option issued under the 2015 Plan was estimated using the Black-Scholes option-pricing model that used the following weighted-average assumptions: Six months ended September 30, 2018 2017 Expected term (in years) 6.1 6.1 Risk-free interest rate 2.7 % 2.1 % Expected volatility 41.4 % 40.1 % Expected dividend yield — % — % Estimated grant date fair value per ordinary share $ 36.75 $ 25.23 The weighted-average per share fair value of options granted to employees during the six months ended September 30, 2018 and 2017 was $16.28 and $10.58, respectively. As of September 30, 2018, the number of options and awards available for future grant under the 2015 Plan was 6,387,854. Share option activity under the 2015 Plan and the Historical Plans for the six months ended September 30, 2018 was as follows: Number of Awards Weighted Average Exercise Price (2) Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) (1) Outstanding as of March 31, 2018 6,229,860 $ 13.78 7.40 $ 134,859 Options granted 2,142,948 $ 36.75 Options exercised (1,011,211 ) $ 7.69 Options forfeited and cancelled (197,757 ) $ 21.49 Outstanding as of September 30, 2018 7,163,840 $ 21.29 7.89 $ 147,726 Exercisable as of September 30, 2018 2,176,150 $ 10.30 6.05 $ 68,721 (1) The aggregate intrinsic value for share options outstanding and exercisable as of September 30, 2018 was calculated based on the positive difference, if any, between the closing price of the Company’s ordinary shares on the NASDAQ Global Select Market on September 30, 2018, and the exercise price of the underlying options. (2) Certain of the Company’s option grants have an exercise price denominated in British pounds. The weighted-average exercise price at the end of each reporting period was translated into U.S. dollars using the exchange rate at the end of the period. The weighted-average exercise price for the options granted, exercised, forfeited and expired was translated into U.S. dollars using the exchange rate at the applicable date of grant, exercise, forfeiture or expiration, as appropriate. The total intrinsic value of options exercised was $34.8 million for the six months ended September 30, 2018. Total cash proceeds from option exercises was $7.8 million for the six months ended September 30, 2018. As of September 30, 2018, there was approximately $51.8 million of unrecognized share-based compensation related to unvested share options, which is expected to be recognized over a weighted-average period of 3.05 years. ESPP Initially, a total of 1.1 million shares of the Company's ordinary shares were reserved for future issuance under the ESPP. This number is subject to change in the event of a share split, share dividend or other change in capitalization. The ESPP may be terminated or amended by the board of directors at any time. The ESPP permits eligible employees to purchase shares by authorizing payroll deductions from 1% to 10% of his or her eligible compensation during each six month offering period, which starts on the first business day in January and July each year. Unless an employee has previously withdrawn from the offering, his or her accumulated payroll deductions will be used to purchase shares on the last day of the offering period at a price equal to 85% of the fair market value of the shares on the first business day or last business day of the offering period, whichever is lower. In the three and six months ended September 30, 2018, the Company recognized $0.3 million and $0.5 million of share-based compensation expense under the ESPP. As of September 30, 2018, there were 1.0 million shares of the Company's ordinary shares available for future issuance under the ESPP. Restricted Share Units (RSUs) The Company grants RSUs to its Non-Employee Directors and its employees. Non-Employee Directors receive an initial RSU grant upon joining the BOD that vests over three years and an annual grant each year thereafter that vests fully on the one-year anniversary of the grant date. RSUs granted to Company employees vest in four equal annual installments. RSU activity under the 2015 Plan for the six months ended September 30, 2018 was as follows: Number of Shares Weighted Average Grant Date Fair Value Intrinsic Value (1) (2) Unvested restricted share units as of March 31, 2018 32,763 $ 23.06 $ 1,161 Restricted share units granted 413,722 $ 37.30 15,433 Restricted share units vested (18,102 ) $ 22.55 698 Restricted share units canceled (9,582 ) $ 34.82 386 Unvested restricted share units as of September 30, 2018 418,801 $ 36.88 $ 15,447 (1 ) The intrinsic value of unvested shares as of September 30, 2018 was calculated based on the closing price of the Company’s ordinary shares on the NASDAQ Global Select Market on September 30, 2018, multiplied by the number of unvested RSUs. (2) The intrinsic value of RSUs granted, vested and canceled is calculated based on the closing price of the Company’s ordinary shares at the respective transaction dates multiplied by the number of RSUs. As of September 30, 2018, there was approximately $13.8 million of unrecognized share-based compensation expense related to unvested RSUs, which is expected to be recognized over a weighted-average period of 3.38 years. Share-based compensation expense recognized under the 2015 Plan, Historical Plans and ESPP in the accompanying condensed consolidated statements of operations was as follows: Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Cost of revenue $ 420 $ 236 $ 824 $ 442 Research and development 1,571 601 2,901 1,283 Sales and marketing 1,965 1,122 3,796 2,070 General and administrative 2,153 951 3,769 1,761 Total share-based compensation expense $ 6,109 $ 2,910 $ 11,290 $ 5,556 In certain situations, the board of directors has approved modifications to employee share option agreements, including acceleration of vesting or the removal of exercise restrictions for share options for which the service-based vesting has been satisfied which resulted in additional share-based compensation expense. The total modification expense included in the table above for the three months ended September 30, 2018 and 2017 was $0.4 million and $0.1 million, respectively. The total modification expense included in the table above for the six months ended September 30, 2018 and 2017 was $0.6 million and $0.4 million, respectively. As of September 30, 2018, the Company had unrecognized compensation of $2.5 million related to modified share-based awards that will be recognized over a remaining requisite service period of 0.5 years.

Comprehensive Loss

Comprehensive Loss	6 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Comprehensive Loss	11. Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions, other events, and circumstances from non-owner sources. Comprehensive loss consists of net loss and other comprehensive income (loss), which includes certain changes in equity that are excluded from net loss. Specifically, cumulative foreign currency translation adjustments and unrealized gains and losses on investments are included in accumulated other comprehensive loss. As of September 30, 2018 and March 31, 2018, accumulated other comprehensive loss is presented separately on the condensed consolidated balance sheets and consists of cumulative foreign currency translation adjustments and unrealized gains and losses on investments.

Acquisitions

Acquisitions	6 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions	12. Acquisitions Solebit LABS Ltd. On July 31, 2018, the Company entered into a share purchase agreement (the Purchase Agreement) pursuant to which it acquired Solebit LABS Ltd. (Solebit), a company organized under the laws of the State of Israel, that provides security software. Solebit’s technology enhances security for the Company’s customers and adds to its ability to detect and prevent cyber-attacks, zero day threats and malware across email and the web in real time. This acquisition further enhances the Company’s cyber resilience platform architecture. Prior to the closing of the acquisition, the Company held an ownership interest in Solebit of approximately 1.5%. Upon completion of the acquisition, the Company recognized a gain of $0.3 million recorded in foreign exchange expense and other, net within the condensed consolidated statement of operations for the remeasurement of its previously held ownership interest to fair value, which was $0.8 million. The total preliminary purchase price of $96.5 million included cash payments of approximately $96.1 million, inclusive of $8.8 million in purchase price held in escrow. The escrow is being held in respect of claims for indemnification for one year from the purchase date. The preliminary amounts due from sellers of $0.5 million includes working capital adjustments and certain preliminary one-year indemnification period purchase price adjustments identified by the Company. The preliminary purchase price, cash payments and purchase price allocation are subject to finalization of amounts due from the seller for the one-year indemnification period adjustments and potential working capital adjustments. The Company expects to finalize the purchase price within the required one-year measurement period. The acquisition of Solebit has been accounted for as a business combination and, in accordance with ASC 805, Business Combinations Preliminary purchase consideration: Total cash paid, net of acquired cash $ 85,733 Cash and cash equivalents acquired 10,410 Preliminary amounts due from sellers (492 ) Fair value of previously held asset 828 Total preliminary purchase price consideration $ 96,479 Fair value of assets acquired and liabilities assumed: Cash and cash equivalents $ 10,410 Prepaid expenses and other current assets 75 Intangible assets 16,964 Goodwill 74,395 Total assets acquired 101,844 Accounts payable (18 ) Accrued expenses and other current liabilities (2,335 ) Deferred revenue (663 ) Other non-current liabilities (2,349 ) Total fair value of assets acquired and liabilities assumed $ 96,479 In the three and six months ended September 30, 2018, acquisition-related expenses were $0.6 million and $1.0 million, respectively. Acquisition-related expenses have been included primarily in general and administrative expenses in the condensed consolidated statements of operations. The operating results of Solebit are included in the condensed consolidated statements of operations beginning on the acquisition date. The significant intangible assets identified in the preliminary purchase price allocation discussed above include developed technology and customer relationships, which are amortized over their respective useful lives on a straight-line basis when the pattern in which their economic benefits will be consumed cannot be reliably determined. To value the developed technology asset, the Company utilized the income approach, specifically a discounted cash-flow method known as the multi-period excess earnings method. Customer relationships represent the underlying relationships with certain customers to provide ongoing services for products sold. The Company utilized the income approach, specifically the distribution method, a subset of the excess-earnings method to value the customer relationships. A portion of the purchase price has been allocated to intangible assets and goodwill, respectively, and is reflected in the tables above. The fair value of the assets acquired and liabilities assumed is less than the purchase price, resulting in the recognition of goodwill. The goodwill reflects the value of the synergies we expect to realize and the assembled workforce and is not deductible for tax purposes. The purchase price has been allocated to the tangible and intangible assets acquired and liabilities assumed based upon the respective estimates of fair value as of the date of the acquisition, which remains preliminary, and using assumptions that the Company’s management believes are reasonable given the information then available. The final allocation of the purchase price may differ materially from the information presented in these condensed consolidated financial statements. Any changes to the preliminary estimates of the fair value of the assets acquired and liabilities assumed during the measurement period will be recorded as adjustments to those assets and liabilities and residual amounts will be allocated to goodwill. The following table presents the estimated fair values and useful lives of the identifiable intangible assets acquired: Amount (in thousands) Estimated Useful Life (in years) Developed technology $ 16,689 10 Customer relationships 235 7 Trade names 40 1 Total identifiable intangible assets $ 16,964 Pro Forma Financial Information (unaudited) The following unaudited pro forma information presents the condensed combined results of operations of the Company and Solebit for the three and six months ended September 30, 2018 and 2017, as if the acquisition of Solebit had been completed on April 1, 2017. These pro forma condensed consolidated financial results have been prepared for comparative purposes only and include certain adjustments that reflect pro forma results of operations such as fair value adjustments (step-downs) for deferred revenue, increased amortization for the fair value of acquired intangible assets and adjustments to eliminate transaction costs incurred by the Company and Solebit. The unaudited pro forma results do not reflect any operating efficiencies or potential cost savings which may result from the consolidation of the operations of the Company and Solebit. Accordingly, these unaudited pro forma results are presented for informational purposes only and are not necessarily indicative of the results of operations that actually would have been achieved had the acquisition occurred as of April 1, 2017, nor are they intended to represent or be indicative of future results of operations (in thousands, except per share amounts): Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Revenue $ 82,275 $ 63,307 $ 161,020 $ 121,672 Net loss (1,311 ) (2,415 ) (5,664 ) (5,214 ) Basic and diluted net loss per share $ (0.02 ) $ (0.04 ) $ (0.10 ) $ (0.09 ) Weighted average number of ordinary shares used in computing basic and diluted net loss per share 59,800 57,027 59,489 56,662 ATAATA, Inc. On July 9, 2018, the Company acquired ATAATA, Inc. (Ataata), a privately-owned company based in the United States, for cash consideration of approximately $25.1 million, net of cash acquired of $1.9 million. Ataata is a cyber security training and awareness platform designed to reduce human error in the workplace and help enable organizations to become more secure by changing the security culture of their employees. The acquisition will allow customers to measure cyber risk training effectiveness by converting behavior observations into actionable risk metrics for security professionals. The addition of security awareness training and risk scoring and analysis strengthens the Company’s cyber resilience for email capabilities. The acquisition of Ataata has been accounted for as a business combination and, in accordance with ASC 805, Business Combinations The preliminary purchase price allocation primarily consisted of $1.5 million of identifiable intangible assets and approximately $22.6 million of goodwill that is not deductible for tax purposes. The identifiable intangible assets primarily include developed technology of $1.4 million and customer relationships of $0.1 million, with estimated useful lives of ten and six years, respectively. The goodwill balance is primarily attributed to the expanded market opportunities when combining Ataata's awareness training technology with the Company’s other offerings. The preliminary purchase price and allocations are subject to finalization of amounts due from the seller inclusive of certain working capital and one-year indemnification period adjustments. In the three and six months ended September 30, 2018, acquisition-related expenses were $0.1 million and $0.5 million, respectively. Acquisition-related expenses have been included primarily in general and administrative expenses in the condensed consolidated statements of operations. The operating results of Ataata are included in the condensed consolidated statements of operations beginning on the acquisition date. The Company has not presented pro forma results of operations for the Ataata acquisition because it is not material to the Company's condensed consolidated results of operations, financial position, or cash flows.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	13. Goodwill and Intangible Assets The following is a rollforward of the Company’s goodwill balance: Goodwill Balance as of March 31, 2018 $ 5,631 Goodwill acquired 97,018 Effect of foreign exchange rates 413 Balance as of September 30, 2018 $ 103,062 Purchased intangible assets consist of the following: Weighted- Average September 30, 2018 Remaining Gross Net Useful Life Carrying Accumulated Carrying (in years) Value Amortization Value Developed technology 10 $ 20,226 $ (595 ) $ 19,631 Customer relationships 6 454 (38 ) 416 Trade Names 1 56 (10 ) 46 Capitalized Software 3 11,835 (2,407 ) 9,428 $ 32,571 $ (3,050 ) $ 29,521 Weighted- Average March 31, 2018 Remaining Gross Net Useful Life Carrying Accumulated Carrying (in years) Value Amortization Value Developed technology 9 $ 1,546 $ (213 ) $ 1,333 Customer relationships 6 108 (21 ) 87 Capitalized Software 3 9,171 (1,329 ) 7,842 10,825 (1,563 ) 9,262 In-process research and development (1) N/A 557 — 557 $ 11,382 $ (1,563 ) $ 9,819 (1) In-process research and development assets were placed in service in the three months ended September 30, 2018. The Company recorded amortization expense of $1.2 million and $2.0 million for the three and six months ended September 30, 2018. Amortization relating to developed technology and capitalized software was recorded within cost of revenue and amortization of customer relationships and trade names was recorded within sales and marketing expenses. Future estimated amortization expense of intangible assets as of September 30, 2018, is as follows: Purchased Intangible Assets Capitalized Software Remainder of 2019 $ 1,097 $ 1,653 2020 2,165 3,384 2021 2,143 2,615 2022 2,143 1,273 2023 2,143 471 Thereafter 10,402 32 Total $ 20,093 $ 9,428

Debt

Debt	6 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	14. Debt On July 23, 2018, the Company entered into a credit agreement (the Credit Agreement) with certain lenders, and JPMorgan Chase Bank, N.A., as administrative agent (the Administrative Agent), which provided the Company with a $100.0 million senior secured term loan and a $50.0 million senior secured revolving credit facility (collectively, the Credit Facility). The proceeds of the Credit Facility, net of $2.3 million of debt issuance costs, are available to fund working capital and for other corporate purposes, including to finance permitted acquisitions and investments. Interest under the Credit Facility accrues at a rate between LIBOR plus 1.375% and LIBOR plus 1.875%, based on the Company’s ratio of indebtedness to earnings before interest, taxes, depreciation, amortization and certain other adjustments (Consolidated EBITDA). Based on this ratio, the current interest rate as of September 30, 2018 under the Credit Facility is LIBOR plus 1.625%. The term of the Credit Facility is five years, maturing on July 23, 2023. At the time the Company entered into the Credit Agreement, there was no outstanding debt. The Credit Agreement has financial covenants that require the Company to maintain a Consolidated Secured Leverage Ratio (as defined in the Credit Agreement), commencing on September 30, 2018, of not more than 3.00 to 1.00 for the four consecutive fiscal quarter period ending on the last day of each fiscal quarter (the Reference Period), with a step-up to 3.50 to 1.00 for any four-quarter period in which the Company consummates a permitted acquisition having an aggregate purchase price in excess of $25,000,000. The Company must also maintain a Consolidated Interest Expense Ratio (as defined in the Credit Agreement) of 3.00 to 1.00 commencing on September 30, 2018 and for each Reference Period thereafter. The Company was in compliance with all covenants as of September 30, 2018. The Company allocated debt issuance costs on a pro-rata basis between the senior secured term loan and senior secured revolving credit facility. The debt issuance costs on the senior secured term loan are recorded as a reduction of debt and are amortized and recognized as additional interest expense over the life of the debt instrument using the effective interest method. The debt issuance costs on the senior secured revolving credit facility are recorded in other assets and are amortized and recognized as additional interest expense over the life of the senior secured revolving credit facility on a straight-line basis. As of September 30, 2018, the balance of debt issuance costs recorded as a reduction of debt was $1.4 million and the balance of debt issuance costs recorded in other assets was $0.7 million. All obligations under the Credit Agreement are unconditionally guaranteed by all of the Company’s material direct and indirect subsidiaries organized under the laws of the United States, the United Kingdom, the Bailiwick of Jersey, and other jurisdictions agreed to by the Company and the Administrative Agent, with certain exceptions. These guarantees are secured by substantially all of the present and future property and assets of the guarantors, with certain exclusions. As of September 30, 2018, the Company had $99.4 million outstanding on the senior secured term loan and had no outstanding borrowings under the senior secured revolving credit facility. Total availability under the senior secured revolving credit facility is reduced by outstanding letters of credit of $3.9 million. As of September 30, 2018, total availability under the senior secured revolving credit facility was $46.1 million. Future minimum principal payment obligations under the senior secured term loan are as follows: Year Ending March 31, Debt Remainder of 2019 $ 1,250 2020 4,375 2021 6,875 2022 9,375 2023 10,000 2024 67,500 Total minimum debt payments $ 99,375 Less: Debt issuance costs (1,407 ) Less: Current portion of long-term debt (2,814 ) Long-term debt $ 95,154

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	15. Commitments and Contingencies Leases Capital leases The Company has entered into various capital lease arrangements for computer equipment with non-cancelable terms through January 2022. As of September 30, 2018, future minimum commitments for capital leases were as follows: Year Ending March 31, Capital Leases Remainder of 2019 $ 722 2020 1,102 2021 1,102 2022 326 Total minimum lease payments $ 3,252 Less: Amount representing interest (196 ) Present value of capital lease obligations 3,056 Less: Current portion (1,164 ) Long-term portion of capital lease obligations $ 1,892 Construction financing lease obligations The Company leases certain facilities under build-to-suit leases whereby the Company is deemed to be the owner of the building during the construction period for accounting purposes. For build-to-suit leases, the Company recorded certain estimated construction costs incurred and reported to it by the landlord for the buildings as an asset and corresponding construction financing lease obligation on the condensed consolidated balance sheets. Since the Company’s unit of account is related only to its portion of the buildings, the Company determined that it does not have land leases and has not recorded rent expense attributable to the land. Any incremental costs incurred directly by the Company are also capitalized. In each reporting period, the landlord estimates and reports to the Company construction costs incurred to date for the buildings and the Company records its portion using allocation estimates. The Company periodically meets with the landlord and its construction manager to review these estimates and observe construction progress before recording such amounts. Lexington, MA - U.S. Headquarters The construction of the Company’s Lexington, MA – U.S. headquarters was substantially completed during the quarter ended March 31, 2018, and because the Company concluded it had a collateralized letter of credit of $1.3 million, the Company did not meet the sale-leaseback criteria for derecognition of the building asset and liability. As a result, the Company continues to be the deemed owner of the building and will treat the lease as a financing obligation and depreciate the asset in accordance with the Company’s accounting policy. The monthly rent payments made to the lessor under the lease agreement are recorded in the Company’s financial statements as principal and interest on the financing obligation. For the three and six months ended September 30, 2018, interest expense on lease financing obligations was $0.5 million and $0.9 million, respectively. As of September 30, 2018, the future estimated commitments related to the financing obligations were $38.5 million and $10.2 million for principal and interest, respectively, through January 31, 2028. London, U.K. - U.K. Headquarters In January 2018, the Company entered into an Agreement for Lease (AFL) for its new U.K. headquarters located in London, England (UK Building). The AFL was entered into around the time the landlord had commenced a construction project to refurbish the UK Building and includes terms and conditions that are in effect during the construction project. Additionally, the AFL includes Leases in Agreed Form (Leases) to be executed upon completion of the construction project, which is expected in or around February 2019. Under the terms of the AFL and Leases, the Company will initially lease approximately 113,000 square feet of space for 56.50 British pounds per square foot per year over an initial noncancelable term of 10 years after initial occupancy, which is expected in the Company’s third fiscal quarter of 2020. The Company determined that it will account for the AFL as a build-to-suit lease as of March 31, 2018. As of September 30, 2018, Property and equipment, net, includes $40.6 million related to the UK Building and construction costs for the UK Building. The construction financing lease obligation related to the UK Building was $39.7 million and was incurred by the landlord only and no cash was paid to the landlord by us related to the UK Building since lease inception. Once the landlord completes the construction of the UK Building, the Company will evaluate the AFL and Leases in order to determine whether or not the AFL and Leases meet the criteria for “sale-leaseback” treatment. If the AFL and Leases meet the “sale-leaseback” criteria, the Company will remove the asset and the related liability from its condensed consolidated balance sheet and treat the Leases as either an operating or a capital lease based on the Company’s assessment of the accounting guidance. If the Company continues to be the deemed owner, the Company will treat the AFL and Leases as a financing obligation and will depreciate the asset in accordance with the Company’s accounting policy. Litigation The Company, from time to time, may be party to litigation arising in the ordinary course of its business. The Company was not subject to any material legal proceedings during the three and six months ended September 30, 2018 and 2017, and, to the best of its knowledge, no material legal proceedings are currently pending or threatened. Indemnification The Company typically enters into indemnification agreements with customers in the ordinary course of business. Pursuant to these agreements, the Company indemnifies and agrees to reimburse the indemnified party for losses suffered or incurred as a result of claims of intellectual property infringement. These indemnification agreements are provisions of the applicable customer agreement. Based on when clients first sign an agreement for the Company’s service, the maximum potential amount of future payments the Company could be required to make under certain of these indemnification agreements is unlimited. Based on historical experience and information known as of September 30, 2018 and March 31, 2018, the Company has not incurred any costs for the above guarantees and indemnities. In certain circumstances, the Company warrants that its services will perform in all material respects in accordance with its standard published specification documentation in effect at the time of delivery of the services to the customer for the term of the agreement. To date, the Company has not incurred significant expense under its warranties and, as a result, the Company believes the estimated fair value of these agreements is immaterial.

Segment and Geographic Informat

Segment and Geographic Information	6 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment and Geographic Information	16. Segment and Geographic Information Geographic Data The Company allocates, for the purpose of geographic data reporting, its revenue based upon the location of the contracting subsidiary. Total revenue by geographic area was as follows: Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Revenue: United States $ 41,135 $ 31,076 $ 79,068 $ 60,268 United Kingdom 25,114 19,635 49,670 37,502 South Africa 11,014 9,393 22,636 18,174 Other 4,906 2,962 9,199 5,280 Total revenue $ 82,169 $ 63,066 $ 160,573 $ 121,224 Property and equipment, net by geographic location consists of the following: As of September 30, As of March 31, 2018 2018 United States (1) $ 61,601 $ 62,064 United Kingdom (2) 56,039 46,664 South Africa 5,821 6,512 Australia 3,333 3,953 Other 4,814 4,629 Total $ 131,608 $ 123,822 (1) Includes construction costs capitalized under financing lease obligations related to the Company’s U.S. build-to-suit facilities of $37.8 million and $39.4 million as of September 30, 2018 and March 31, 2018, respectively. (2) Includes construction costs capitalized under financing lease obligations related to the Company’s U.K. build-to-suit facility of $40.6 million and $31.2 million as of September 30, 2018 and March 31, 2018, respectively.

Income Taxes

Income Taxes	6 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	17. Income Taxes The provision for income taxes for the three months ended September 30, 2018 and 2017 was $0.6 million and $0.4 million, respectively, on the loss before income taxes of $(1.4) million and $(0.9) million, respectively. The provision for income taxes for the six months ended September 30, 2018 and 2017 was $1.5 million and $0.9 million, respectively, on the loss before income taxes of $(4.0) million and $(2.4) million, respectively. The provision for income taxes for the three and six months ended September 30, 2018 was primarily attributable to the tax provision provided on the earnings in the Company’s South African entity, partially offset by the tax benefit provided on the loss in the Company’s Israel entity. In addition, during the three months ended September 30, 2018, the Company recorded a discrete tax benefit of $0.4 million for the release of a portion of the Company’s pre-existing U.S. valuation allowance as a result of the Ataata business combination. The provision for income taxes for the three and six months ended September 30, 2017 was primarily attributable to earnings in the Company’s U.S. and South African entities offset by $3.0 million and $4.2 million, respectively in excess tax benefits resulting from share option exercises by employees. In assessing the Company’s ability to realize its net deferred tax assets, the Company considered various factors including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and recent financial operations to determine whether it is more likely than not that some portion or all of its net deferred tax assets will not be realized. Based upon these factors, the Company has determined that the uncertainty regarding the realization of these assets is sufficient to warrant the need for a full valuation allowance against its net deferred tax assets as of September 30, 2018. As of September 30, 2018 and March 31, 2018, the Company had liabilities for uncertain tax positions of $6.0 million and $6.2 million, respectively, none of which, if recognized, would impact the Company’s effective tax rate. Interest and penalty charges, if any, related to uncertain tax positions would be classified as income tax expense in the accompanying condensed consolidated statements of operations. As of September 30, 2018 and March 31, 2018, accrued interest or penalties related to uncertain tax positions are immaterial. During the third quarter of fiscal 2018, the Tax Cuts and Jobs Act (the Act) was enacted in the United States. Additionally, during the third quarter of fiscal 2018, Staff Accounting Bulletin No. 118 ("SAB 118") was issued to address the application of US GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. The Company did not adjust any of its provisional estimates during the three months ended September 30, 2018. The Company will continue to refine its calculations as additional analysis is completed during the measurement period. In addition, the Company’s estimates may also be affected as the Company gains a more thorough understanding of changes to the tax law resulting from the passage of the Act. The Company anticipates completing its assessment of the impact of the Act during the third quarter 2019.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Pronouncements	6 Months Ended
	Sep. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Recently Issued and Adopted Accounting Pronouncements	18. Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies and adopted by the Company as of the specified effective date. Recently Adopted Accounting Pronouncements On April 1, 2018, the Company adopted ASU No. 2014-09, Revenue from Contracts with Customers: Topic 606 On April 1, 2018 the Company adopted ASU No. 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities On April 1, 2018 the Company adopted ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments On April 1, 2018 the Company adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory On April 1, 2018 the Company adopted ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash On April 1, 2018 the Company adopted ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business On April 1, 2018 the Company adopted ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting On July 1, 2018, the Company adopted ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-24): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 , Leases (Topic 842) In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326). The Company is currently in the process of evaluating the impact and timing of adoption of the In January 2017, the FASB issued ASU No. 2017-04 , Simplifying the Test for Goodwill Impairment

Subsequent Events

Subsequent Events	6 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events

Principles of Consolidation (Po

Principles of Consolidation (Policies)	6 Months Ended
	Sep. 30, 2018
Risks And Uncertainties [Abstract]
Basis of Presentation	Basis of Presentation The accompanying interim condensed consolidated financial statements are unaudited. These financial statements and notes should be read in conjunction with the audited consolidated financial statements for the year ended March 31, 2018 and related notes, together with management’s discussion and analysis of financial condition and results of operations, contained in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on May 29, 2018. The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States (GAAP) have been condensed or omitted. In the opinion of management, the unaudited condensed consolidated financial statements and notes have been prepared on the same basis as the audited consolidated financial statements for the year ended March 31, 2018 contained in the Company’s Annual Report on Form 10-K and include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the Company’s financial position as of September 30, 2018, and for the three and six months ended September 30, 2018 and 2017. These interim periods are not necessarily indicative of the results to be expected for any other interim period or the full year. The Company reclassified $0.1 million of provision for doubtful accounts to accounts receivable within its condensed consolidated statements of cash flows for the six months ended September 30, 2017 in this quarterly report on Form 10-Q to conform to current period presentation. This had no impact on the Company’s previously reported results of operations or its balance sheets. The accompanying condensed consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the condensed consolidated financial statements. As of September 30, 2018, the Company’s significant accounting policies and estimates, which are detailed in the Company’s Annual Report on Form 10-K, have not changed, except as discussed below.
Revenue Recognition	Revenue Recognition Adoption of ASC 606 Effective April 1, 2018, the Company adopted the requirements of Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers: Topic 606 Revenue Recognition Revenue Recognition Policy Under ASC 606 the Company recognizes revenue upon transfer of control of promised products or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. To achieve the core principle of ASC 606, the Company performs the following steps: 1) Identify the contract(s) with a customer; 2) Identify the performance obligations in the contract; 3) Determine the transaction price; 4) Allocate the transaction price to the performance obligations in the contract; and 5) Recognize revenue when (or as) we satisfy a performance obligation. The Company derives its revenue from two sources: (1) subscription revenues, which are comprised of subscription fees from customers accessing the Company’s cloud services and from customers purchasing additional support beyond the standard support that is included in the basic subscription fees; and (2) related professional services and other revenue, which consists primarily of certain performance obligations related to set-up, ingestion, consulting and training fees. In the three and six months ended September 30, 2018 and 2017, subscription revenue made up the substantial majority of the Company’s revenue and professional services and other revenue made up less than 5% of the Company’s revenue. The Company’s subscription arrangements provide customers the right to access the Company’s hosted software applications. Customers do not have the right to take possession of the Company’s software during the hosting arrangement. The Company sells its products and services directly through the Company’s sales force and also indirectly through third-party resellers. In accordance with the provisions of ASC 606, the Company has considered certain factors in determining whether the end-user or the third-party reseller is the customer in arrangements involving resellers. The Company concluded that in the majority of transactions with resellers, the reseller is the customer. In these arrangements, the Company considered that it is the reseller, and not the Company, that has the relationship with the end-user. Specifically, the reseller has the ability to set pricing with the end-user and the credit risk with the end-user is borne by the reseller. Further, the reseller is not obligated to report its transaction price with the end-user to the Company, and in the majority of transactions, the Company is unable to determine the amount paid by the end-user customer to the reseller in these transactions. As a result of such considerations, revenue for these transactions is presented in the accompanying condensed consolidated statements of operations based upon the amount billed to the reseller. For transactions where we have determined that the end-user is the ultimate customer, revenue is presented in the accompanying condensed consolidated statements of operations based on the transaction price with the end-user. The Company recognizes subscription and support revenue ratably over the term of the contract, typically one year in duration, beginning on the date the customer is provided access to the Company’s service. For performance obligations related to set-up and ingestion, including implementation assistance and data migration services, respectively, the Company recognizes revenue using output measures of performance that reflect the transfer of promised services to the customer consistent with progress to completion. The Company recognizes revenue on training, consulting, and other professional services contracts using output measures of performance as services are completed. Training, consulting, and other professional services are considered separate performance obligations. Amounts that have been invoiced are recorded in accounts receivable and in deferred revenue or revenue, depending on whether the revenue recognition criteria have been met. The Company primarily bills and collects payments from customers for its services in advance on a monthly and annual basis. In some instances, the Company receives non-refundable upfront payments for activities that do not constitute a promise to transfer a service and therefore are considered administrative tasks, not separate performance obligations. The upfront payments are evaluated to determine whether a material right to a discount upon renewal of the subscription exists. When the Company concludes a material right does not exist, the Company recognizes revenue related to the upfront payment over the initial contract term. When the Company concludes a material right does exist, the Company recognizes revenue related to the upfront payment, under the look-through method, over the estimated customer benefit period, which has been determined to be six years. All of the Company’s performance obligations, and associated revenue, are generally transferred to customers over time, with the exception of training, consulting and other professional services, which are generally transferred to the customer at a point in time. Revenue is presented net of any taxes collected from customers. 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 standalone selling price basis. The Company determines the standalone selling prices based on the Company’s overall pricing objectives, taking into consideration market conditions and other factors, including the value of the Company’s contracts, the products sold, customer demographics, the Company’s sales channel, and the number and size of users within the Company’s contracts. Deferred revenue primarily consists of billings or payments received in advance of revenue recognition from subscription and other services described above and is recognized as the revenue recognition criteria are met. Deferred revenue that is expected to be recognized during the succeeding twelve-month period is recorded as current deferred revenue and the remaining portion is recorded as non-current in the accompanying condensed Deferred Cost Policy As part of the Company’s adoption of ASC 606 , the Company capitalizes incremental costs of obtaining revenue contracts, which primarily consist of commissions paid to its sales representatives. The Company amortizes these commissions over six years on a systematic basis, consistent with the pattern of transfer of the goods or services to which the asset relates. Six years represents the estimated benefit period of the customer relationship taking into account factors such as peer estimates of technology lives and customer lives as well as the Company's own historical data. No commissions are paid related to contract renewals. The current and noncurrent portions of deferred commissions are included in deferred contract costs, net, and deferred contract costs, net of current portion, respectively, in the accompanying condensed consolidated balance sheets. Impact of Adoption of ASC 606 The adoption of ASC 606 resulted in a decrease to deferred revenue of $6.0 million and an increase of $23.8 million in deferred contract costs as of April 1, 2018. The Company recorded the deferred tax impact associated with the cumulative-effect adjustment of adopting ASC 606 to accumulated deficit with an equal and offsetting adjustment to the Company’s valuation allowance. The decrease to deferred revenue upon adoption was primarily due to a change in the accounting treatment for certain upfront fees that were accounted for as a single unit of account under Legacy GAAP and are accounted for as separate performance obligations under ASC 606. The increase in deferred contract costs was the result of the capitalization of certain commissions that were determined to be incremental costs of obtaining a contract. Under Legacy GAAP, the Company expensed all commission costs as incurred. As a result of the adoption of ASC 606, the Company’s accumulated deficit decreased by $29.9 million as of April 1, 2018, which was the net cumulative impact associated with the capitalization of sales commissions and the adjustment to deferred revenue. The cumulative effect of the changes made to the Company’s April 1, 2018 balance sheet for the adoption of ASC 606 were as follows: Balance as of March 31, 2018 Adjustments Due to Adoption of ASC 606 Balance as of April 1, 2018 Assets Deferred contract costs, net $ — $ 5,494 $ 5,494 Deferred contract costs, net of current portion — 18,339 18,339 Liabilities Deferred revenue 123,057 (517 ) 122,540 Deferred revenue, net of current portion 18,045 (5,526 ) 12,519 Shareholders' equity Accumulated deficit (106,507 ) 29,876 (76,631 ) In accordance with the requirements of ASC 606, the disclosure for the quantitative effect and the significant changes between the reported results under ASC 606 and those that would have been reported under Legacy GAAP on our unaudited condensed Three months ended September 30, 2018 As Reported - ASC 606 Amounts without Adoption of ASC 606 Effect of Change Increase/(Decrease) Income Statement Revenues $ 82,169 $ 81,447 $ 722 Operating expenses Sales and marketing (34,705 ) (37,330 ) (2,625 ) Net loss $ (2,058 ) $ (5,405 ) $ 3,347 Six months ended September 30, 2018 As Reported - ASC 606 Amounts without Adoption of ASC 606 Effect of Change Increase/(Decrease) Income Statement Revenues $ 160,573 $ 159,555 $ 1,018 Operating expenses Sales and marketing (68,908 ) (73,797 ) (4,889 ) Net loss $ (5,529 ) $ (11,436 ) $ 5,907 As of September 30, 2018 As Reported - ASC 606 Balances without Adoption of ASC 606 Effect of Change Increase/(Decrease) Balance Sheet Assets Deferred contract costs, net $ 6,265 $ — $ 6,265 Deferred contract costs, net of current portion 21,319 — 21,319 Liabilities Deferred revenue 124,894 124,758 136 Deferred revenue, net of current portion 11,722 18,688 (6,966 ) Shareholders' equity Accumulated deficit (82,160 ) (117,943 ) 35,783 Revenue recognized during the three and six months ended September 30, 2018 from amounts included in deferred revenue at the beginning of the period was approximately $53.4 million and $84.5 million, respectively. Revenue recognized during the three and six months ended September 30, 2018 from performance obligations satisfied or partially satisfied in previous periods was not material. The adoption of ASC 606 had no impact to net operating cash flows. Contracted revenue as of September 30, 2018 that has not yet been recognized (“contracted not recognized”) was $74.0 million, which includes deferred revenue and non-cancellable amounts that will be invoiced and recognized as revenue in future periods and excludes contracts with an original expected length of one year or less. The Company expects 51% of contracted and not recognized revenue to be recognized over the next twelve months, 45% in years two and three, with the remaining balance recognized thereafter.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of income and expenses during the reporting period. Significant estimates relied upon in preparing these condensed consolidated financial statements include revenue recognition, variable consideration, valuation at fair value of assets acquired or sold, including intangibles, goodwill, tangible assets, and liabilities assumed, amortization periods, expected future cash flows used to evaluate the recoverability of long-lived assets, contingent liabilities, construction financing lease obligations, restructuring liabilities, expensing and capitalization of research and development costs for internal-use software, the determination of the fair value of share-based awards issued, the average period of benefit associated with costs capitalized to obtain revenue contracts and the recoverability of the Company’s net deferred tax assets and related valuation allowance. Although the Company regularly assesses these estimates, actual results could differ materially from these estimates. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results may differ from management’s estimates if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. Changes in estimates are recorded in the period in which they become known.
Subsequent Events Considerations	Subsequent Events Considerations The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure.
Concentration Of Credit Risk And Off Balance Sheet Risk	5. Concentration of Credit Risk and Off-Balance Sheet Risk The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments, which potentially subject the Company to concentrations of credit risk, consist primarily of cash and cash equivalents, investments and accounts receivable. The Company maintains its cash, cash equivalents and investments with major financial institutions of high-credit quality. Although the Company deposits its cash with multiple financial institutions, its deposits, at times, may exceed federally insured limits. Credit risk with respect to accounts receivable is dispersed due to our large number of customers. The Company’s accounts receivable are derived from revenue earned from customers primarily located in the United States, the United Kingdom and South Africa. The Company generally does not require its customers to provide collateral or other security to support accounts receivable. Credit losses historically have not been significant and the Company generally has not experienced any material losses related to receivables from individual customers, or groups of customers. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company’s accounts receivable. As of September 30, 2018 and March 31, 2018, no individual customer represented more than 10% of the Company’s accounts receivable. During the three and six months ended September 30, 2018 and 2017, no individual customer represented more than 10% of the Company’s revenue. As of September 30, 2018, the Company’s investments consisted primarily of investment-grade fixed income corporate debt securities with maturities ranging from less than one month to five months and non-U.S. government securities with maturities in approximately one month. We diversify our investment portfolio by investing in multiple types of investment-grade securities and attempt to mitigate a risk of loss by using a third-party investment manager.
Internal-use Software Costs	Software Development Costs Costs incurred to develop software applications used in the Company’s SaaS platform consist of certain direct costs of materials and services incurred in developing or obtaining internal-use computer software, and payroll and payroll-related costs for employees who are directly associated with, and who devote time to, the project. These costs generally consist of internal labor during configuration, coding, and testing activities. Research and development costs incurred during the preliminary project stage or costs incurred for data conversion activities, training, maintenance and general and administrative or overhead costs are expensed as incurred. Once an application has reached the development stage, internal and external costs, if direct and incremental, are capitalized until the application is substantially complete and ready for its intended use. Qualified costs incurred during the operating stage of the Company’s software applications relating to upgrades and enhancements are capitalized to the extent it is probable that they will result in added functionality, while costs incurred for maintenance of, and minor upgrades and enhancements to, internal-use software are expensed as incurred. During the three and six months ended September 30, 2018 and 2017, the Company believes the substantial majority of its development efforts were either in the preliminary project stage of development or in the operation stage (post-implementation), and accordingly, no costs have been capitalized during these periods. These costs are included in the accompanying condensed consolidated statements of operations as research and development expense. Cloud-computing Arrangements The Company evaluates its accounting for fees paid in cloud computing arrangements (CCA) including determining whether the CCA includes a license to internal-use software. If the CCA includes a software license, the Company accounts for the software license as an intangible asset. Acquired software licenses are recognized and measured at cost, which includes the present value of the license obligation if the license is to be paid for over time. If the CCA does not include a software license, the Company accounts for the arrangement as a service contract (hosting arrangement) and hosting costs are generally expensed as incurred. Upon adoption of ASU 2018-15, the Company evaluates upfront costs including implementation, set-up or other costs (collectively, implementation costs) for hosting arrangements under the internal-use software framework. Costs related to preliminary project activities and post implementation activities are expensed as incurred, whereas costs incurred in the development stage are generally capitalized. Capitalized implementation costs are amortized on a straight-line basis over the expected term of the hosting arrangement, which includes consideration of the noncancellable contractual term and reasonably certain renewals. During the three and six months ended September 30, 2018, the Company capitalized $0.9 million of implementation costs related to hosting arrangements that were incurred during the application development stage. These capitalized implementation costs will be amortized over the expected term of the arrangement determined to be four years through sales and marketing expense within the condensed consolidated statements of operations.
Recently Issued Accounting Pronouncements	Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies and adopted by the Company as of the specified effective date. Recently Adopted Accounting Pronouncements On April 1, 2018, the Company adopted ASU No. 2014-09, Revenue from Contracts with Customers: Topic 606 On April 1, 2018 the Company adopted ASU No. 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities On April 1, 2018 the Company adopted ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments On April 1, 2018 the Company adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory On April 1, 2018 the Company adopted ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash On April 1, 2018 the Company adopted ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business On April 1, 2018 the Company adopted ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting On July 1, 2018, the Company adopted ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-24): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 , Leases (Topic 842) In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326). The Company is currently in the process of evaluating the impact and timing of adoption of the In January 2017, the FASB issued ASU No. 2017-04 , Simplifying the Test for Goodwill Impairment
Cash and Cash Equivalents	The Company considers all highly liquid instruments purchased with an original maturity date of 90 days or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist of cash on deposit with banks, amounts held in interest-bearing money market funds and investments with maturities of 90 days or less from the date of purchase. Cash equivalents are carried at cost, which approximates their fair market value. Investments not classified as cash equivalents are presented as either short-term or long-term investments based on both their stated maturities as well as the time period the Company intends to hold such securities. The Company determines the appropriate classification of investments at the time of purchase and reevaluates such designation at each balance sheet date. The Company adjusts the cost of investments for amortization of premiums and accretion of discounts to maturity. The Company includes such amortization and accretion in interest income.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Tables) - ASU 2014-09 [Member]	6 Months Ended
	Sep. 30, 2018
Schedule of Cumulative Effect of Changes to Balance Sheet	The cumulative effect of the changes made to the Company’s April 1, 2018 balance sheet for the adoption of ASC 606 were as follows: Balance as of March 31, 2018 Adjustments Due to Adoption of ASC 606 Balance as of April 1, 2018 Assets Deferred contract costs, net $ — $ 5,494 $ 5,494 Deferred contract costs, net of current portion — 18,339 18,339 Liabilities Deferred revenue 123,057 (517 ) 122,540 Deferred revenue, net of current portion 18,045 (5,526 ) 12,519 Shareholders' equity Accumulated deficit (106,507 ) 29,876 (76,631 )
Schedule of Quantitative Effect and Significant Changes Between ASC 606 and Legacy GAAP on Unaudited Condensed Consolidated Income Statement and Balance Sheet	In accordance with the requirements of ASC 606, the disclosure for the quantitative effect and the significant changes between the reported results under ASC 606 and those that would have been reported under Legacy GAAP on our unaudited condensed Three months ended September 30, 2018 As Reported - ASC 606 Amounts without Adoption of ASC 606 Effect of Change Increase/(Decrease) Income Statement Revenues $ 82,169 $ 81,447 $ 722 Operating expenses Sales and marketing (34,705 ) (37,330 ) (2,625 ) Net loss $ (2,058 ) $ (5,405 ) $ 3,347 Six months ended September 30, 2018 As Reported - ASC 606 Amounts without Adoption of ASC 606 Effect of Change Increase/(Decrease) Income Statement Revenues $ 160,573 $ 159,555 $ 1,018 Operating expenses Sales and marketing (68,908 ) (73,797 ) (4,889 ) Net loss $ (5,529 ) $ (11,436 ) $ 5,907 As of September 30, 2018 As Reported - ASC 606 Balances without Adoption of ASC 606 Effect of Change Increase/(Decrease) Balance Sheet Assets Deferred contract costs, net $ 6,265 $ — $ 6,265 Deferred contract costs, net of current portion 21,319 — 21,319 Liabilities Deferred revenue 124,894 124,758 136 Deferred revenue, net of current portion 11,722 18,688 (6,966 ) Shareholders' equity Accumulated deficit (82,160 ) (117,943 ) 35,783

Cash, Cash Equivalents and In_2

Cash, Cash Equivalents and Investments (Tables)	6 Months Ended
	Sep. 30, 2018
Cash And Cash Equivalents [Abstract]
Schedule Of Cash, Cash Equivalents And Investments	The following is a summary of cash, cash equivalents and investments as of September 30, 2018 and March 31, 2018: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value September 30, 2018: Cash and cash equivalents due in 90 days or less $ 118,881 $ — $ — $ 118,881 Investments: Non-U.S. government securities due in one year or less 2,996 15 — 3,011 Corporate securities due in one year or less 22,488 18 (26 ) 22,480 Total investments 25,484 33 (26 ) 25,491 Total cash, cash equivalents and investments $ 144,365 $ 33 $ (26 ) $ 144,372 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value March 31, 2018: Cash and cash equivalents due in 90 days or less $ 78,339 $ — $ — $ 78,339 Investments: U.S. treasury securities due in one year or less 2,995 — (5 ) 2,990 Non-U.S. government securities due in one year or less 5,996 1 (1 ) 5,996 Corporate securities due in one year or less 49,969 8 (92 ) 49,885 Total investments 58,960 9 (98 ) 58,871 Total cash, cash equivalents and investments $ 137,299 $ 9 $ (98 ) $ 137,210

Disclosure of Fair Value of F_2

Disclosure of Fair Value of Financial Instruments (Tables)	6 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured and Recorded at Fair Value on Recurring Basis	The following table summarizes financial assets measured and recorded at fair value on a recurring basis in the accompanying condensed consolidated balance sheets as of September 30, 2018 and March 31, 2018, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: September 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1 Inputs) Significant Other Observable Inputs (Level 2 Inputs) Total Assets: Money market funds $ 7,785 $ — $ 7,785 Non-U.S. government securities — 3,011 3,011 Corporate securities — 22,480 22,480 Total assets $ 7,785 $ 25,491 $ 33,276 March 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1 Inputs) Significant Other Observable Inputs (Level 2 Inputs) Total Assets: Money market funds $ 10,143 $ — $ 10,143 U.S. treasury securities — 2,990 2,990 Non-U.S. government securities — 5,996 5,996 Corporate securities — 49,885 49,885 Total assets $ 10,143 $ 58,871 $ 69,014

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Dilutive Ordinary Shares Excluded from Calculation of Diluted Weighted Average Shares Outstanding	The following potentially dilutive ordinary share equivalents have been excluded from the calculation of diluted weighted-average shares outstanding as their effect would have been anti-dilutive for the periods presented (in thousands): Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Share options outstanding 7,164 7,425 7,164 7,425 Unvested restricted share units 419 44 419 44 ESPP shares 64 70 64 70

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Weighted Average Assumption Utilized to Determine Fair Value of Option	The fair value of each share option issued under the 2015 Plan was estimated using the Black-Scholes option-pricing model that used the following weighted-average assumptions: Six months ended September 30, 2018 2017 Expected term (in years) 6.1 6.1 Risk-free interest rate 2.7 % 2.1 % Expected volatility 41.4 % 40.1 % Expected dividend yield — % — % Estimated grant date fair value per ordinary share $ 36.75 $ 25.23
Schedule of Share-Based Compensation, Stock Options, Activity	Share option activity under the 2015 Plan and the Historical Plans for the six months ended September 30, 2018 was as follows: Number of Awards Weighted Average Exercise Price (2) Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) (1) Outstanding as of March 31, 2018 6,229,860 $ 13.78 7.40 $ 134,859 Options granted 2,142,948 $ 36.75 Options exercised (1,011,211 ) $ 7.69 Options forfeited and cancelled (197,757 ) $ 21.49 Outstanding as of September 30, 2018 7,163,840 $ 21.29 7.89 $ 147,726 Exercisable as of September 30, 2018 2,176,150 $ 10.30 6.05 $ 68,721 (1) The aggregate intrinsic value for share options outstanding and exercisable as of September 30, 2018 was calculated based on the positive difference, if any, between the closing price of the Company’s ordinary shares on the NASDAQ Global Select Market on September 30, 2018, and the exercise price of the underlying options. (2) Certain of the Company’s option grants have an exercise price denominated in British pounds. The weighted-average exercise price at the end of each reporting period was translated into U.S. dollars using the exchange rate at the end of the period. The weighted-average exercise price for the options granted, exercised, forfeited and expired was translated into U.S. dollars using the exchange rate at the applicable date of grant, exercise, forfeiture or expiration, as appropriate.
Schedule of Share-Based Compensation, Restricted Share Units, Activity	RSU activity under the 2015 Plan for the six months ended September 30, 2018 was as follows: Number of Shares Weighted Average Grant Date Fair Value Intrinsic Value (1) (2) Unvested restricted share units as of March 31, 2018 32,763 $ 23.06 $ 1,161 Restricted share units granted 413,722 $ 37.30 15,433 Restricted share units vested (18,102 ) $ 22.55 698 Restricted share units canceled (9,582 ) $ 34.82 386 Unvested restricted share units as of September 30, 2018 418,801 $ 36.88 $ 15,447 (1 ) The intrinsic value of unvested shares as of September 30, 2018 was calculated based on the closing price of the Company’s ordinary shares on the NASDAQ Global Select Market on September 30, 2018, multiplied by the number of unvested RSUs. (2) The intrinsic value of RSUs granted, vested and canceled is calculated based on the closing price of the Company’s ordinary shares at the respective transaction dates multiplied by the number of RSUs.
Share-Based Compensation Expense Recognized in Statements of Operations	Share-based compensation expense recognized under the 2015 Plan, Historical Plans and ESPP in the accompanying condensed consolidated statements of operations was as follows: Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Cost of revenue $ 420 $ 236 $ 824 $ 442 Research and development 1,571 601 2,901 1,283 Sales and marketing 1,965 1,122 3,796 2,070 General and administrative 2,153 951 3,769 1,761 Total share-based compensation expense $ 6,109 $ 2,910 $ 11,290 $ 5,556

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Summary of Preliminary Purchase Price Allocation	The following table summarizes the preliminary purchase price allocation recorded in the quarter ended September 30, 2018 (in thousands): Preliminary purchase consideration: Total cash paid, net of acquired cash $ 85,733 Cash and cash equivalents acquired 10,410 Preliminary amounts due from sellers (492 ) Fair value of previously held asset 828 Total preliminary purchase price consideration $ 96,479 Fair value of assets acquired and liabilities assumed: Cash and cash equivalents $ 10,410 Prepaid expenses and other current assets 75 Intangible assets 16,964 Goodwill 74,395 Total assets acquired 101,844 Accounts payable (18 ) Accrued expenses and other current liabilities (2,335 ) Deferred revenue (663 ) Other non-current liabilities (2,349 ) Total fair value of assets acquired and liabilities assumed $ 96,479
Summary of Estimated Fair Values and Useful Lives of Identifiable Intangible	The following table presents the estimated fair values and useful lives of the identifiable intangible assets acquired: Amount (in thousands) Estimated Useful Life (in years) Developed technology $ 16,689 10 Customer relationships 235 7 Trade names 40 1 Total identifiable intangible assets $ 16,964
Summary of Pro Forma Financial Information (unaudited)	Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Revenue $ 82,275 $ 63,307 $ 161,020 $ 121,672 Net loss (1,311 ) (2,415 ) (5,664 ) (5,214 ) Basic and diluted net loss per share $ (0.02 ) $ (0.04 ) $ (0.10 ) $ (0.09 ) Weighted average number of ordinary shares used in computing basic and diluted net loss per share 59,800 57,027 59,489 56,662

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill Balance	The following is a rollforward of the Company’s goodwill balance: Goodwill Balance as of March 31, 2018 $ 5,631 Goodwill acquired 97,018 Effect of foreign exchange rates 413 Balance as of September 30, 2018 $ 103,062
Schedule of Purchased Intangible Assets	Purchased intangible assets consist of the following: Weighted- Average September 30, 2018 Remaining Gross Net Useful Life Carrying Accumulated Carrying (in years) Value Amortization Value Developed technology 10 $ 20,226 $ (595 ) $ 19,631 Customer relationships 6 454 (38 ) 416 Trade Names 1 56 (10 ) 46 Capitalized Software 3 11,835 (2,407 ) 9,428 $ 32,571 $ (3,050 ) $ 29,521 Weighted- Average March 31, 2018 Remaining Gross Net Useful Life Carrying Accumulated Carrying (in years) Value Amortization Value Developed technology 9 $ 1,546 $ (213 ) $ 1,333 Customer relationships 6 108 (21 ) 87 Capitalized Software 3 9,171 (1,329 ) 7,842 10,825 (1,563 ) 9,262 In-process research and development (1) N/A 557 — 557 $ 11,382 $ (1,563 ) $ 9,819 (1) In-process research and development assets were placed in service in the three months ended September 30, 2018.
Schedule of Future Estimated Amortization Expense of Acquired Intangible Assets	Future estimated amortization expense of intangible assets as of September 30, 2018, is as follows: Purchased Intangible Assets Capitalized Software Remainder of 2019 $ 1,097 $ 1,653 2020 2,165 3,384 2021 2,143 2,615 2022 2,143 1,273 2023 2,143 471 Thereafter 10,402 32 Total $ 20,093 $ 9,428

Debt (Tables)

Debt (Tables)	6 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Future Minimum Principal Payment Obligations	Future minimum principal payment obligations under the senior secured term loan are as follows: Year Ending March 31, Debt Remainder of 2019 $ 1,250 2020 4,375 2021 6,875 2022 9,375 2023 10,000 2024 67,500 Total minimum debt payments $ 99,375 Less: Debt issuance costs (1,407 ) Less: Current portion of long-term debt (2,814 ) Long-term debt $ 95,154

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Commitments Under Capital Leases	As of September 30, 2018, future minimum commitments for capital leases were as follows: Year Ending March 31, Capital Leases Remainder of 2019 $ 722 2020 1,102 2021 1,102 2022 326 Total minimum lease payments $ 3,252 Less: Amount representing interest (196 ) Present value of capital lease obligations 3,056 Less: Current portion (1,164 ) Long-term portion of capital lease obligations $ 1,892

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	6 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Summary of Revenue by Geographic Area	The Company allocates, for the purpose of geographic data reporting, its revenue based upon the location of the contracting subsidiary. Total revenue by geographic area was as follows: Three months ended September 30, Six months ended September 30, 2018 2017 2018 2017 Revenue: United States $ 41,135 $ 31,076 $ 79,068 $ 60,268 United Kingdom 25,114 19,635 49,670 37,502 South Africa 11,014 9,393 22,636 18,174 Other 4,906 2,962 9,199 5,280 Total revenue $ 82,169 $ 63,066 $ 160,573 $ 121,224
Summary of Property and Equipment, Net by Geographic Location	Property and equipment, net by geographic location consists of the following: As of September 30, As of March 31, 2018 2018 United States (1) $ 61,601 $ 62,064 United Kingdom (2) 56,039 46,664 South Africa 5,821 6,512 Australia 3,333 3,953 Other 4,814 4,629 Total $ 131,608 $ 123,822 (1) Includes construction costs capitalized under financing lease obligations related to the Company’s U.S. build-to-suit facilities of $37.8 million and $39.4 million as of September 30, 2018 and March 31, 2018, respectively. (2) Includes construction costs capitalized under financing lease obligations related to the Company’s U.K. build-to-suit facility of $40.6 million and $31.2 million as of September 30, 2018 and March 31, 2018, respectively.

Organization and Basis of Pre_3

Organization and Basis of Presentation - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Apr. 01, 2018	Mar. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Prior period reclassification of provision for doubtful accounts to accounts receivable				$ 100,000
Maximum percentage of revenue contribution from professional services and other revenue	5.00%	5.00%	5.00%	5.00%
Upfront ingestion fee to be recognized over estimated customer benefit period			6 years
Accumulated deficit decreased	$ (82,160,000)		$ (82,160,000)			$ (106,507,000)
Revenue recognized included in deferred revenue	53,400,000		84,500,000
Contracted revenue not yet recognized	74,000,000		$ 74,000,000
ASU 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Amortization period of deferred contract costs			6 years
Payment of commissions related to contract renewals			$ 0
Accumulated deficit decreased					$ (76,631,000)
ASU 2014-09 [Member] | Adjustments Due to Adoption of Topic 606
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
(Decrease) to deferred revenue					(6,000,000)
Increase in deferred contract costs					23,800,000
Accumulated deficit decreased	$ 35,783,000		$ 35,783,000		$ 29,876,000

Organization and Basis of Pre_4

Organization and Basis of Presentation - Schedule of Cumulative Effect of Changes to Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 01, 2018	Mar. 31, 2018
Assets
Deferred contract costs, net	$ 6,265
Deferred contract costs, net of current portion	21,319
Liabilities
Deferred revenue	124,894		$ 123,057
Deferred revenue, net of current portion	11,722		18,045
Shareholders' equity
Accumulated deficit	(82,160)		$ (106,507)
ASU 2014-09 [Member]
Assets
Deferred contract costs, net		$ 5,494
Deferred contract costs, net of current portion		18,339
Liabilities
Deferred revenue		122,540
Deferred revenue, net of current portion		12,519
Shareholders' equity
Accumulated deficit		(76,631)
ASU 2014-09 [Member] | Adjustments Due to Adoption of Topic 606
Assets
Deferred contract costs, net	6,265	5,494
Deferred contract costs, net of current portion	21,319	18,339
Liabilities
Deferred revenue	136	(517)
Deferred revenue, net of current portion	(6,966)	(5,526)
Shareholders' equity
Accumulated deficit	$ 35,783	$ 29,876

Organization and Basis of Pre_5

Organization and Basis of Presentation - Schedule of Quantitative Effect and Significant Changes Between ASC 606 and Legacy GAAP on Unaudited Condensed Consolidated Income Statement and Balance Sheet (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Apr. 01, 2018	Mar. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 82,169	$ 63,066	$ 160,573	$ 121,224
Operating expenses
Sales and marketing	(34,705)	(30,155)	(68,908)	(57,714)
Net loss	(2,058)	$ (1,339)	(5,529)	$ (3,239)
Assets
Deferred contract costs, net	6,265		6,265
Deferred contract costs, net of current portion	21,319		21,319
Liabilities
Deferred revenue	124,894		124,894			$ 123,057
Deferred revenue, net of current portion	11,722		11,722			18,045
Shareholders' equity
Accumulated deficit	(82,160)		(82,160)			$ (106,507)
ASU 2014-09 [Member]
Assets
Deferred contract costs, net					$ 5,494
Deferred contract costs, net of current portion					18,339
Liabilities
Deferred revenue					122,540
Deferred revenue, net of current portion					12,519
Shareholders' equity
Accumulated deficit					(76,631)
ASU 2014-09 [Member] | Amounts without Adoption of Topic 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	81,447		159,555
Operating expenses
Sales and marketing	(37,330)		(73,797)
Net loss	(5,405)		(11,436)
Liabilities
Deferred revenue	124,758		124,758
Deferred revenue, net of current portion	18,688		18,688
Shareholders' equity
Accumulated deficit	(117,943)		(117,943)
ASU 2014-09 [Member] | Effect of Change Higher/(Lower) [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	722		1,018
Operating expenses
Sales and marketing	(2,625)		(4,889)
Net loss	3,347		5,907
Assets
Deferred contract costs, net	6,265		6,265		5,494
Deferred contract costs, net of current portion	21,319		21,319		18,339
Liabilities
Deferred revenue	136		136		(517)
Deferred revenue, net of current portion	(6,966)		(6,966)		(5,526)
Shareholders' equity
Accumulated deficit	$ 35,783		$ 35,783		$ 29,876

Organization and Basis of Pre_6

Organization and Basis of Presentation - Additional Information (Detail 1)	Sep. 30, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue, remaining performance obligation, percentage	51.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-10-01
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue, remaining performance obligation, percentage	45.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue, remaining performance obligation, percentage	45.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 years

Concentration of Credit Risk _2

Concentration of Credit Risk and Off-Balance Sheet Risk - Additional Information (Detail) - Customer	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018
Concentration Risk [Line Items]
Number of customers representing more than 10% of accounts receivable	0		0		0
Number of customers representing more than 10% of revenue	0	0	0	0
Non-U.S. Government Securities [Member]
Concentration Risk [Line Items]
Investment maturity period			1 month
Minimum [Member] | Corporate Securities [Member]
Concentration Risk [Line Items]
Investment maturity period			1 month
Maximum [Member] | Corporate Securities [Member]
Concentration Risk [Line Items]
Investment maturity period			5 months

Cash, Cash Equivalents and In_3

Cash, Cash Equivalents and Investments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash And Cash Equivalents [Abstract]
Realized gains or losses on investments	$ 0	$ 0	$ 0	$ 0
Aggregate fair value of investments	$ 13,500,000		$ 13,500,000

Cash, Cash Equivalents and In_4

Cash, Cash Equivalents and Investments - Schedule of Cash, Cash Equivalents and Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Cash And Cash Equivalents [Line Items]
Cash and cash equivalents due in 90 days or less, Cost	$ 118,881	$ 78,339
Investments, Cost	25,484	58,960
Total cash, cash equivalents and investments, Cost	144,365	137,299
Investments, Gross unrealized gains	33	9
Investments, Gross unrealized losses	(26)	(98)
Investments, Estimated fair value	25,491	58,871
Cash and cash equivalents due in 90 days or less, Estimated fair value	118,881	78,339
Total cash, cash equivalents and investments, Estimated fair value	144,372	137,210
Total cash, cash equivalents and investments, Estimated fair value, Gross unrealized gains	33	9
Total cash, cash equivalents and investments, Estimated fair value, Gross unrealized losses	(26)	(98)
U.S. Treasury Securities Due in One Year or Less [Member]
Cash And Cash Equivalents [Line Items]
Investments, Cost		2,995
Investments, Gross unrealized losses		(5)
Investments, Estimated fair value		2,990
Non-U.S. Government Securities Due in One Year or Less [Member]
Cash And Cash Equivalents [Line Items]
Investments, Cost	2,996	5,996
Investments, Gross unrealized gains	15	1
Investments, Gross unrealized losses		(1)
Investments, Estimated fair value	3,011	5,996
Corporate Securities Due in One Year or Less [Member]
Cash And Cash Equivalents [Line Items]
Investments, Cost	22,488	49,969
Investments, Gross unrealized gains	18	8
Investments, Gross unrealized losses	(26)	(92)
Investments, Estimated fair value	$ 22,480	$ 49,885

Disclosure of Fair Value of F_3

Disclosure of Fair Value of Financial Instruments - Additional Information (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($)	Sep. 30, 2018	Mar. 31, 2018
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets measured at fair value on a recurring basis	$ 33,276,000	$ 69,014,000
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets measured at fair value on a recurring basis	0	0
Liabilities measured at fair value on a recurring basis	$ 0	$ 0

Disclosure of Fair Value of F_4

Disclosure of Fair Value of Financial Instruments - Summary of Financial Assets Measured and Recorded at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Assets:
Total assets	$ 33,276	$ 69,014
Money Market Funds [Member]
Assets:
Total assets	7,785	10,143
U.S. Treasury Securities [Member]
Assets:
Total assets		2,990
Non-U.S. Government Securities [Member]
Assets:
Total assets	3,011	5,996
Corporate Securities [Member]
Assets:
Total assets	22,480	49,885
Quoted Prices in Active Markets for Identical Assets (Level 1 Inputs) [Member]
Assets:
Total assets	7,785	10,143
Quoted Prices in Active Markets for Identical Assets (Level 1 Inputs) [Member] | Money Market Funds [Member]
Assets:
Total assets	7,785	10,143
Significant Other Observable Inputs (Level 2 Inputs) [Member]
Assets:
Total assets	25,491	58,871
Significant Other Observable Inputs (Level 2 Inputs) [Member] | U.S. Treasury Securities [Member]
Assets:
Total assets		2,990
Significant Other Observable Inputs (Level 2 Inputs) [Member] | Non-U.S. Government Securities [Member]
Assets:
Total assets	3,011	5,996
Significant Other Observable Inputs (Level 2 Inputs) [Member] | Corporate Securities [Member]
Assets:
Total assets	$ 22,480	$ 49,885

Internal-use Software Costs - A

Internal-use Software Costs - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Research And Development [Abstract]
Capitalized costs	$ 0	$ 0	$ 0	$ 0
Implementation costs capitalized	$ 900,000		$ 900,000
Amortization of capitalized implementation costs expected term			4 years

Net Loss Per Share - Dilutive O

Net Loss Per Share - Dilutive Ordinary Shares Excluded from Calculation of Diluted Weighted Average Shares Outstanding (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive ordinary share equivalents excluded from calculation of diluted weighted-average shares outstanding	7,164	7,425	7,164	7,425
Unvested Restricted Share Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive ordinary share equivalents excluded from calculation of diluted weighted-average shares outstanding	419	44	419	44
ESPP Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive ordinary share equivalents excluded from calculation of diluted weighted-average shares outstanding	64	70	64	70

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018USD ($)CompensationPlanshares	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)CompensationPlanInstallment$ / sharesshares	Sep. 30, 2017USD ($)$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-based compensation plans | CompensationPlan	4		4
Weighted average per share fair value of options granted to employees | $ / shares			$ 16.28	$ 10.58
Total intrinsic value of options exercised			$ 34,800
Proceeds from exercises of share-based awards			7,800
Unrecognized share-based compensation expense	$ 51,800		$ 51,800
Unrecognized share-based compensation expense, net of estimated forfeiture, period for recognition			3 years 18 days
Share-based compensation expense recognized	6,109	$ 2,910	$ 11,290	$ 5,556
Employee share option agreements, modification expense	400	$ 100	600	$ 400
Unvested Restricted Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 13,800		$ 13,800
Unrecognized share-based compensation expense, net of estimated forfeiture, period for recognition			3 years 4 months 17 days
Unvested Restricted Share Units [Member] | Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, vesting period			3 years
Unvested Restricted Share Units [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vesting installment for equity granted | Installment			4
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options available for future grant | shares	6,387,854		6,387,854
2015 Employee Share Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options available for future grant | shares	1,000,000		1,000,000
Ordinary shares reserved and authorized for issuance | shares	1,100,000		1,100,000
Authorized payroll deductions percentage	10.00%		10.00%
Share-based compensation arrangement by share-based payment award, term			6 months
Percentage of fair market value of shares to be considered as share price			85.00%
Share-based compensation expense recognized	$ 300		$ 500
2015 Employee Share Purchase Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized payroll deductions percentage			1.00%
2015 Plan, Historical Plans and ESPP [Member] | Modified Share-based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 2,500		$ 2,500
Unrecognized share-based compensation expense, net of estimated forfeiture, period for recognition			6 months

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Weighted-Average Assumption Utilized to Determine Fair Value of Option (Detail) - $ / shares	6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate	2.70%	2.10%
Expected volatility	41.40%	40.10%
Estimated grant date fair value per ordinary share	$ 36.75	$ 25.23

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Share-Based Compensation, Stock Options, Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Sep. 30, 2018	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Awards, Beginning balance	6,229,860
Number of Awards, Options granted	2,142,948
Number of Awards, Options exercised	(1,011,211)
Number of Awards, Options forfeited and cancelled	(197,757)
Number of Awards, Ending balance	7,163,840	6,229,860
Number of Awards, Exercisable	2,176,150
Weighted Average Exercise Price, Beginning balance	$ 13.78
Weighted Average Exercise Price, Options granted	36.75
Weighted Average Exercise Price, Options exercised	7.69
Weighted Average Exercise Price, Options forfeited and cancelled	21.49
Weighted Average Exercise Price, Ending balance	21.29	$ 13.78
Weighted Average Exercise Price Exercisable	$ 10.30
Weighted Average Remaining Contractual Term, Outstanding	7 years 10 months 20 days	7 years 4 months 24 days
Weighted Average Remaining Contractual Term, Exercisable	6 years 18 days
Aggregate Intrinsic Value, Outstanding	$ 147,726	$ 134,859
Aggregate Intrinsic Value, Exercisable	$ 68,721

Share-Based Compensation - Sc_2

Share-Based Compensation - Schedule of Share-Based Compensation, Restricted Share Units, Activity (Detail) - Restricted Share Units (RSUs) [Member] $ / shares in Units, $ in Thousands	6 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares, Unvested restricted share units, Beginning balance | shares	32,763
Number of Shares, Restricted share units granted | shares	413,722
Number of Shares, Restricted share units vested | shares	(18,102)
Number of Shares, Restricted share units canceled | shares	(9,582)
Number of Shares, Unvested restricted share units, Ending balance | shares	418,801
Weighted Average Grant Date Fair Value, Unvested restricted share units, Beginning balance | $ / shares	$ 23.06
Weighted Average Grant Date Fair Value, Restricted share units granted | $ / shares	37.30
Weighted Average Grant Date Fair Value, Restricted share units vested | $ / shares	22.55
Weighted Average Grant Date Fair Value, Restricted share units canceled | $ / shares	34.82
Weighted Average Grant Date Fair Value, Unvested restricted share units, Ending balance | $ / shares	$ 36.88
Intrinsic Value, Unvested restricted share units | $	$ 1,161
Intrinsic Value, Restricted share units granted | $	15,433
Intrinsic Value, Restricted share units vested | $	698
Intrinsic Value, Restricted share units canceled | $	386
Intrinsic Value, Unvested restricted share units | $	$ 15,447

Share-Based Compensation - Shar

Share-Based Compensation - Share-Based Compensation Expense Recognized in Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 6,109	$ 2,910	$ 11,290	$ 5,556
Cost of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	420	236	824	442
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	1,571	601	2,901	1,283
Sales and Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	1,965	1,122	3,796	2,070
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 2,153	$ 951	$ 3,769	$ 1,761

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 09, 2018	Sep. 30, 2018	Sep. 30, 2018	Mar. 31, 2018
Business Acquisition [Line Items]
Net of cash acquired				$ 108,913
Estimated fair values of identifiable intangible assets, amount	$ 16,964
Goodwill			$ 103,062	$ 103,062	$ 5,631
Developed Technology [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, amount	$ 16,689
Estimated Useful Life (in years)	10 years			10 years	9 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, amount	$ 235
Estimated Useful Life (in years)	7 years			6 years	6 years
Solebit Labs Ltd. [Member] | Israel [Member]
Business Acquisition [Line Items]
Business acquisition, agreement date of acquisition	Jul. 31, 2018
Ownership interest before acquisition	1.50%
Fair value of previously held asset	$ 800		828
Preliminary purchase price	96,500		96,479
Cash payment	96,100
Preliminary amounts due from sellers	500		492	$ 492
Purchase price consideration held in escrow	$ 8,800
Business combination, indemnification period	1 year
Acquisition-related expenses			600	1,000
Net of cash acquired			85,733
Estimated fair values of identifiable intangible assets, amount			16,964	16,964
Goodwill			74,395	74,395
Solebit Labs Ltd. [Member] | Israel [Member] | Foreign Exchange Expense and Other Net [Member]
Business Acquisition [Line Items]
Gain recognized before acquisition	$ 300
Ataata [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, amount		$ 1,500
Goodwill		22,600
Ataata [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, amount		$ 1,400
Estimated Useful Life (in years)		10 years
Ataata [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, amount		$ 100
Estimated Useful Life (in years)		6 years
Ataata [Member] | United States [Member]
Business Acquisition [Line Items]
Cash payment		$ 25,100
Acquisition-related expenses			$ 100	$ 500
Business acquisition, effective date of acquisition		Jul. 9, 2018
Net of cash acquired		$ 1,900

Acquisitions - Summary of Preli

Acquisitions - Summary of Preliminary Purchase Price Allocation (Detail) - USD ($) $ in Thousands	Jul. 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Mar. 31, 2018
Preliminary purchase consideration:
Total cash paid, net of acquired cash			$ 108,913
Fair value of assets acquired and liabilities assumed:
Intangible assets	$ 16,964
Goodwill		$ 103,062	103,062	$ 5,631
Solebit Labs Ltd. [Member] | Israel [Member]
Preliminary purchase consideration:
Total cash paid, net of acquired cash		85,733
Cash and cash equivalents acquired		10,410	10,410
Preliminary amounts due from sellers	(500)	(492)	(492)
Fair value of previously held asset	800	828
Total preliminary purchase price consideration	$ 96,500	96,479
Fair value of assets acquired and liabilities assumed:
Cash and cash equivalents acquired		10,410	10,410
Prepaid expenses and other current assets		75	75
Intangible assets		16,964	16,964
Goodwill		74,395	74,395
Total assets acquired		101,844	101,844
Accounts payable		(18)	(18)
Accrued expenses and other current liabilities		(2,335)	(2,335)
Deferred revenue		(663)	(663)
Other non-current liabilities		(2,349)	(2,349)
Total fair value of assets acquired and liabilities assumed		$ 96,479	$ 96,479

Acquisitions - Summay of Estima

Acquisitions - Summay of Estimated Fair Values and Useful Lives of Identifiable Intangible (Detail) - USD ($) $ in Thousands	Jul. 31, 2018	Sep. 30, 2018	Mar. 31, 2018
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, Amount	$ 16,964
Developed Technology [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, Amount	$ 16,689
Estimated Useful Life (in years)	10 years	10 years	9 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, Amount	$ 235
Estimated Useful Life (in years)	7 years	6 years	6 years
Trade Names [Member]
Business Acquisition [Line Items]
Estimated fair values of identifiable intangible assets, Amount	$ 40
Estimated Useful Life (in years)	1 year	1 year

Acquisitions - Summary of Pro F

Acquisitions - Summary of Pro Forma Financial Information (unaudited) (Detail) - Solebit Labs Ltd. [Member] - Israel [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Revenue	$ 82,275	$ 63,307	$ 161,020	$ 121,672
Net loss	$ (1,311)	$ (2,415)	$ (5,664)	$ (5,214)
Basic and diluted net loss per share	$ (0.02)	$ (0.04)	$ (0.10)	$ (0.09)
Weighted average number of ordinary shares used in computing basic and diluted net loss per share	59,800	57,027	59,489	56,662

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill Balance (Detail) $ in Thousands	6 Months Ended
	Sep. 30, 2018USD ($)
Goodwill Roll Forward
Beginning balance	$ 5,631
Goodwill acquired	97,018
Effect of foreign exchange rates	413
Ending balance	$ 103,062

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	Jul. 31, 2018	Sep. 30, 2018	Mar. 31, 2018
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Value		$ 32,571	$ 10,825
Accumulated Amortization		(3,050)	(1,563)
Finite-Lived Intangible Assets, Net Carrying Value		29,521	9,262
Intangible Assets, Gross Carrying Value			11,382
Intangible assets, net		$ 29,521	9,819
In-Process Research and Development [Member]
Finite Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Net Carrying Value			$ 557
Developed Technology [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-Average Remaining Useful Life (in years)	10 years	10 years	9 years
Finite-Lived Intangible Assets, Gross Carrying Value		$ 20,226	$ 1,546
Accumulated Amortization		(595)	(213)
Finite-Lived Intangible Assets, Net Carrying Value		$ 19,631	$ 1,333
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-Average Remaining Useful Life (in years)	7 years	6 years	6 years
Finite-Lived Intangible Assets, Gross Carrying Value		$ 454	$ 108
Accumulated Amortization		(38)	(21)
Finite-Lived Intangible Assets, Net Carrying Value		$ 416	$ 87
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-Average Remaining Useful Life (in years)	1 year	1 year
Finite-Lived Intangible Assets, Gross Carrying Value		$ 56
Accumulated Amortization		(10)
Finite-Lived Intangible Assets, Net Carrying Value		$ 46
Capitalized Software [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-Average Remaining Useful Life (in years)		3 years	3 years
Finite-Lived Intangible Assets, Gross Carrying Value		$ 11,835	$ 9,171
Accumulated Amortization		(2,407)	(1,329)
Finite-Lived Intangible Assets, Net Carrying Value		$ 9,428	$ 7,842

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 1.2	$ 2

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Future Estimated Amortization Expense of Acquired Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Net Carrying Value	$ 29,521	$ 9,262
Purchased Intangible Assets [Member]
Finite Lived Intangible Assets [Line Items]
Remainder of 2019	1,097
2,020	2,165
2,021	2,143
2,022	2,143
2,023	2,143
Thereafter	10,402
Finite-Lived Intangible Assets, Net Carrying Value	20,093
Capitalized Software [Member]
Finite Lived Intangible Assets [Line Items]
Remainder of 2019	1,653
2,020	3,384
2,021	2,615
2,022	1,273
2,023	471
Thereafter	32
Finite-Lived Intangible Assets, Net Carrying Value	$ 9,428	$ 7,842

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Jul. 23, 2018
Senior Secured Term Loan [Member]
Debt Instrument [Line Items]
Debt issuance costs	$ 1,407,000
Outstanding borrowings	99,375,000
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding borrowings	0
Amount available under credit facility	46,100,000
Senior Secured Revolving Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Outstanding borrowings	3,900,000
Senior Secured Revolving Credit Facility [Member] | Other Assets [Member]
Debt Instrument [Line Items]
Debt issuance costs	$ 700,000
Credit Agreement with Certain Lenders [Member]
Debt Instrument [Line Items]
Credit facility term		5 years
Credit facility maturity date		Jul. 23, 2023
Credit facility outstanding debt		$ 0
Credit Agreement with Certain Lenders [Member] | LIBOR Plus [Member]
Debt Instrument [Line Items]
Credit facility current interest rate		1.625%
Credit Agreement with Certain Lenders [Member] | Minimum [Member] | LIBOR Plus [Member]
Debt Instrument [Line Items]
Credit facility interest rate		1.375%
Credit Agreement with Certain Lenders [Member] | Maximum [Member] | LIBOR Plus [Member]
Debt Instrument [Line Items]
Credit facility interest rate		1.875%
Credit Agreement with Certain Lenders [Member] | Senior Secured Term Loan [Member]
Debt Instrument [Line Items]
Credit facility amount		$ 100,000
Credit Agreement with Certain Lenders [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility amount		50,000
Credit Agreement with Certain Lenders [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt issuance costs		$ 2,300
Credit Agreement with Certain Lenders [Member] | Senior Secured Term Loan and Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility financial covenants ratio commencement date	Sep. 30, 2018
Consolidated interest expense ratio	300.00%
Credit facility financial covenants	The Credit Agreement has financial covenants that require the Company to maintain a Consolidated Secured Leverage Ratio (as defined in the Credit Agreement), commencing on September 30, 2018, of not more than 3.00 to 1.00 for the four consecutive fiscal quarter period ending on the last day of each fiscal quarter (the Reference Period), with a step-up to 3.50 to 1.00 for any four-quarter period in which the Company consummates a permitted acquisition having an aggregate purchase price in excess of $25,000,000. The Company must also maintain a Consolidated Interest Expense Ratio (as defined in the Credit Agreement) of 3.00 to 1.00 commencing on September 30, 2018 and for each Reference Period thereafter.
Credit Agreement with Certain Lenders [Member] | Senior Secured Term Loan and Senior Secured Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Secured leverage ratio	300.00%
Aggregate purchase price of acquisition	$ 25,000,000,000
Credit Agreement with Certain Lenders [Member] | Senior Secured Term Loan and Senior Secured Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Secured leverage ratio	350.00%

Debt - Schedule of Future Minim

Debt - Schedule of Future Minimum Principal Payment Obligations (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Debt Instrument [Line Items]
Less: Current portion of long-term debt	$ (2,814)
Long-term debt	95,154
Senior Secured Term Loan [Member]
Debt Instrument [Line Items]
Remainder of 2019	1,250
2,020	4,375
2,021	6,875
2,022	9,375
2,023	10,000
2,024	67,500
Total minimum debt payments	99,375
Less: Debt issuance costs	(1,407)
Less: Current portion of long-term debt	(2,814)
Long-term debt	$ 95,154

Commitments and Contingencies -

Commitments and Contingencies - Future Minimum Commitments Under Capital Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Contractual Obligation Fiscal Year Maturity Schedule [Abstract]
Capital Leases, Remainder of 2019	$ 722
Capital Leases, 2020	1,102
Capital Leases, 2021	1,102
Capital Leases, 2022	326
Total minimum lease payments	3,252
Less: Amount representing interest	(196)
Present value of capital lease obligations	3,056
Less: Current portion	(1,164)	$ (1,125)
Long-term capital lease obligations	$ 1,892	$ 2,390

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2018USD ($)ft²	Sep. 30, 2018USD ($)ft²Gbp_Per_Square_Foot
Commitments And Contingencies [Line Items]
Letters of credit outstanding relating to operating leases	$ 1.3	$ 1.3
Interest expense on lease financial obligation	0.5	0.9
Financial obligation of future estimate commitments, Principal	38.5	38.5
Financial obligation of future estimate commitments, interest	$ 10.2	$ 10.2
Agreement For Lease [Member] | United Kingdom [Member]
Commitments And Contingencies [Line Items]
Area of office space leased | ft²	113,000	113,000
Price per square foot per year | Gbp_Per_Square_Foot		56.50
Lease term		10 years
Lease commenced period		February 2,019
Agreement For Lease [Member] | United Kingdom [Member] | Building [Member]
Commitments And Contingencies [Line Items]
Construction financing lease obligation	$ 39.7	$ 39.7
Agreement For Lease [Member] | United Kingdom [Member] | Building [Member] | Property and equipment, net [Member]
Commitments And Contingencies [Line Items]
Construction costs	$ 40.6	$ 40.6

Segment and Geographic Inform_3

Segment and Geographic Information - Summary of Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 82,169	$ 63,066	$ 160,573	$ 121,224
United States [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	41,135	31,076	79,068	60,268
United Kingdom [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	25,114	19,635	49,670	37,502
South Africa [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	11,014	9,393	22,636	18,174
Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 4,906	$ 2,962	$ 9,199	$ 5,280

Segment and Geographic Inform_4

Segment and Geographic Information - Summary of Property and Equipment, Net by Geographic Location (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Property, plant and equipment, net	$ 131,608	$ 123,822
United States [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, plant and equipment, net	61,601	62,064
United Kingdom [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, plant and equipment, net	56,039	46,664
South Africa [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, plant and equipment, net	5,821	6,512
Australia [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, plant and equipment, net	3,333	3,953
Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Property, plant and equipment, net	$ 4,814	$ 4,629

Segment and Geographic Inform_5

Segment and Geographic Information - Summary of Property and Equipment, Net by Geographic Location (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Mar. 31, 2018
United States [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Construction costs capitalized related to build-to-suit facilities	$ 37.8	$ 39.4
United Kingdom [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Construction costs capitalized related to build-to-suit facilities	$ 40.6	$ 31.2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018
Income Taxes [Line Items]
Provision for income taxes	$ 622,000	$ 421,000	$ 1,480,000	$ 878,000
Loss before income taxes	(1,436,000)	(918,000)	(4,049,000)	(2,361,000)
Discrete tax benefit	400,000
Liabilities for uncertain tax positions	6,000,000		6,000,000		$ 6,200,000
Liabilities for uncertain tax positions, if recognized, that would impact effective tax rate	$ 0		$ 0		$ 0
US and South Africa [Member]
Income Taxes [Line Items]
Excess tax benefits related to exercise of share options		$ 3,000,000		$ 4,200,000