Avalara (AVLR) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	AVLR
Entity Registrant Name	AVALARA, INC.
Entity Central Index Key	0001348036
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		69,950,469

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 146,878		$ 142,322	$ 12,622	$ 14,075
Trade accounts receivable—net of allowance for doubtful accounts of $539 and $521, respectively	45,381	$ 39,482	40,287
Deferred commissions	6,062	4,464	0
Prepaid expenses and other current assets	13,255		11,307
Total current assets before customer fund assets	211,576		193,916
Funds held from customers	19,365		13,113
Receivable from customers—net of allowance of $283 and $198, respectively	1,238		270
Total current assets	232,179		207,299
Noncurrent assets:
Property and equipment—net	33,819		33,373
Goodwill	78,842		61,300
Intangible assets—net	26,440		19,371
Deferred commissions	19,582	14,803	0
Other noncurrent assets	1,824		1,589
Total assets	392,686		322,932
Current liabilities:
Trade payables	9,536		4,847
Accrued expenses	41,600	44,307	42,217
Deferred revenue	131,733	122,103	125,260
Total current liabilities before customer fund obligations	182,869		172,324
Customer fund obligations	20,502		13,349
Total current liabilities	203,371		185,673
Noncurrent liabilities:
Deferred revenue	981	1,300	9,393
Deferred tax liability	599		560
Deferred rent	16,927		17,317
Other noncurrent liabilities	1,835		436
Total liabilities	223,713		213,379
Commitments and contingencies	0		0
Shareholders' equity:
Preferred stock, $0.0001 par value– no shares issued and outstanding at March 31, 2019 and December 31, 2018, and 20,000 shares authorized as of March 31, 2019 and December 31, 2018	0		0
Common stock, $0.0001 par value– 69,903 and 66,769 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively, and 600,000 shares authorized as of March 31, 2019 and December 31, 2018	7		7
Additional paid-in capital	640,996		599,493
Accumulated other comprehensive loss	(2,807)		(2,345)
Accumulated deficit	(469,223)	$ (459,980)	(487,602)
Total shareholders’ equity	168,973		109,553	$ (407,163)	$ (393,592)
Total liabilities and shareholders' equity	$ 392,686		$ 322,932

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Trade accounts receivable, allowance for doubtful accounts	$ 539	$ 521
Receivable from customers, allowance	$ 283	$ 198
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Preferred stock, shares authorized	20,000,000	20,000,000
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares, issued	69,903,000	66,769,000
Common stock, shares, outstanding	69,903,000	66,769,000
Common stock, shares authorized	600,000,000	600,000,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue:
Revenues	$ 84,970	$ 61,377
Cost of revenue:
Cost of revenues	25,307	17,509
Gross profit	59,663	43,868
Operating expenses:
Research and development	15,956	12,619
Sales and marketing	38,208	37,307
General and administrative	15,234	9,211
Total operating expenses	69,398	59,137
Operating loss	(9,735)	(15,269)
Other (income) expense:
Interest income	(767)	(36)
Interest expense	111	894
Other (income) expense, net	48	(30)
Total other (income) expense, net	(608)	828
Loss before income taxes	(9,127)	(16,097)
Provision for (benefit from) income taxes	116	(848)
Net loss	$ (9,243)	$ (15,249)
Net loss per share attributable to common shareholders, basic and diluted	$ (0.14)	$ (2.47)
Weighted average shares of common stock outstanding, basic and diluted	68,381	6,170
Subscription and Returns
Revenue:
Revenues	$ 78,231	$ 57,870
Cost of revenue:
Cost of revenues	20,978	14,817
Professional Services
Revenue:
Revenues	6,739	3,507
Cost of revenue:
Cost of revenues	$ 4,329	$ 2,692

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (9,243)	$ (15,249)
Other comprehensive income (loss)—Foreign currency translation	(462)	603
Total comprehensive loss	$ (9,705)	$ (14,646)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (9,243)	$ (15,249)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,681	2,990
Stock-based compensation	6,560	3,510
Deferred tax expense	39	(1,018)
Amortization of deferred rent	(133)	301
Non-cash change in earnout liability	0	(71)
Non-cash bad debt expense	222	67
Other	58	180
Changes in operating assets and liabilities:
Trade accounts receivable	(5,535)	(6,428)
Prepaid expenses and other current assets	(1,705)	(1,907)
Other long-term assets	(236)	110
Trade payables	3,590	(1,736)
Accrued expenses and other current liabilities	(10,373)	(5,771)
Deferred commissions	(6,377)	0
Deferred revenue	9,031	11,647
Net cash used in operating activities	(10,421)	(13,375)
Cash flows from investing activities:
Net increase in customer fund assets	(7,224)	(18,527)
Cash paid for acquired intangible assets	(131)	0
Cash paid for acquisitions of businesses	(17,310)	0
Purchase of property and equipment	(2,114)	(3,625)
Net cash used in investing activities	(26,779)	(22,152)
Cash flows from financing activities:
Proceeds from credit facility	0	18,000
Payments of deferred financing costs	(39)	0
Net increase in customer fund obligations	7,143	18,527
Proceeds from exercise of stock options and common stock warrants	27,311	326
Proceeds from purchases of stock under employee stock purchase plan	7,664	0
Taxes paid related to net share settlement of stock-based awards	(93)	(2,016)
Repurchase of shares	0	(819)
Net cash provided by financing activities	41,986	34,018
Foreign currency effect on cash and cash equivalents	(230)	56
Net change in cash and cash equivalents	4,556	(1,453)
Cash and cash equivalents—Beginning of period	142,322	14,075
Cash and cash equivalents—End of period	146,878	12,622
Supplemental cash flow disclosures:
Cash paid for interest expense	63	770
Cash paid for income taxes	77	96
Non-cash investing and financing activities:
Accrued purchase price related to acquisitions	2,984	0
Accrued value of earnout related to acquisitions of businesses	5,952	0
Stock issued for acquisitions of intangible assets	50	0
Property and equipment purchased under tenant improvement allowance	0	621
Property and equipment additions in accounts payable and accrued expenses	938	3,719
Deferred financing costs in accounts payable and accrued expenses	272	502
Cashless exercises of options and warrants	5	5,699
Cashless redemptions of options and warrants	$ 98	$ 7,715

Nature of Operations

Nature of Operations	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations	1. Nature of Operations Avalara, Inc. (the “Company”) provides software solutions that help businesses of all types and sizes comply with transaction tax requirements worldwide. The Company offers a broad and growing suite of compliance solutions for transaction taxes, such as sales and use tax, value-added tax (VAT), excise tax, lodging tax, and communications tax. These solutions enable customers to automate the process of determining taxability, identifying applicable tax rates, determining and collecting taxes, preparing and filing returns, remitting taxes, maintaining tax records, and managing compliance documents. The Company, a Washington corporation, was originally incorporated in 1999 and is headquartered in Seattle, Washington. The Company has wholly owned subsidiaries in the United Kingdom, Canada, Belgium, India, and Brazil that provide business development, software development, and support services.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Interim Financial Information The accompanying consolidated financial statements were prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Certain information and disclosures normally included in consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. Accordingly, these consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes for the year ended December 31, 2018, included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on February 28, 2019. The accompanying interim consolidated balance sheet as of March 31, 2019, the consolidated interim statements of operations for the three months ended March 31, 2019 and 2018, the consolidated statements of comprehensive loss for the three months ended March 31, 2019 and 2018, and the consolidated statements of cash flows for the three months ended March 31, 2019 and 2018, are unaudited. The unaudited interim consolidated financial statements have been prepared on a basis consistent with that used to prepare the audited annual consolidated financial statements and include, in the opinion of management, all adjustments, consisting of normal and recurring items, necessary for the fair presentation of the consolidated financial statements. The operating results for the three months ended March 31, 2019 are not necessarily indicative of the results expected for the full year ending December 31, 2019. The Company adopted the new revenue recognition accounting standard, Accounting Standards Codification (“ASC”) 606, effective January 1, 2019 on a modified retrospective basis (see Recently Adopted Accounting Standards Principles of Consolidation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. Segments The Company operates its business as one operating segment. Operating segments are defined as components of an enterprise about which separate financial information is evaluated regularly by the chief operating decision maker, the Company’s Chief Executive Officer, in deciding how to allocate resources and assess performance. The Company’s chief operating decision maker allocates resources and assesses performance based upon discrete financial information at the consolidated level. Use of Estimates The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could materially differ from those estimates. Fair Value Measurements The Company applies the fair value measurement and disclosure provisions of the Accounting Standards Codification. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy prioritizes the inputs used to measure fair value. The hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1 : Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 : Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Level 3 : Inputs are unobservable inputs based on the Company’s assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. The Company’s assessment of the significance of an input to the fair value measurement requires judgment, which may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash equivalents, trade accounts receivable, trade payables, and accrued expenses due to their short-term nature. The carrying amount of the Company’s revolving credit facility, to the extent there is a carrying amount as of the balance sheet date, approximates fair value, considering the interest rate is based on the prime interest rate. Long-Lived Assets The Company evaluates long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. An impairment is recognized in the event the carrying value of such assets is not recoverable. If the carrying value is not recoverable, the fair value is determined and an impairment is recognized for the amount by which the carrying value exceeds the fair value. No impairment of long-lived assets occurred in the first quarter of 2019. Income Taxes The Company’s deferred tax assets and liabilities are determined based on temporary differences between the financial reporting and income tax basis of assets and liabilities and are measured using the enacted tax rates expected to apply in the years when the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that some of the deferred tax assets will not be realized. The Company assesses its income tax positions and records income taxes based upon management’s evaluation of the facts, circumstances, and information available at the reporting date. The Company determines whether its uncertain tax positions are more likely than not to be sustained upon examination based on the technical merits of the position. For tax positions not meeting the more likely than not threshold, the tax amount recognized in the consolidated financial statements is reduced by the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority. Stock-Based Compensation The Company accounts for stock-based compensation by calculating the fair value of each option, common stock warrant, restricted stock unit (“RSU”), or purchase right issued under the Company’s 2018 Employee Stock Purchase Plan (“ESPP”) at the date of grant. The fair value of stock options, common stock warrants, and purchase rights issued under the ESPP is estimated by applying the Black-Scholes option-pricing model. This model uses the fair value of the Company’s underlying common stock at the measurement date, the expected or contractual term of the option, warrant or right, the expected volatility of its common stock, risk-free interest rates, and expected dividend yield of its common stock. The fair value of an RSU is determined using the fair value of the Company’s underlying common stock on the date of grant. Revenue Recognition – ASC 606 The Company primarily generates revenue from fees paid for subscriptions to tax compliance solutions and fees paid for services performed in preparing and filing tax returns on behalf of its customers. Amounts that have been invoiced are recorded in trade accounts receivable and deferred revenue, contract liabilities, or revenue, depending upon whether the revenue recognition criteria have been met. Revenue is recognized once the customer is provisioned and services are provided in an amount that reflects the consideration expected to be entitled to in exchange for those services. The Company’s revenue recognition policy follows guidance from ASC 606, Revenue from Contracts with Customers The Company determines revenue recognition through the following five-step framework: • Identification of the contract, or contracts, with a customer; • Identification of the performance obligations in the contract; • Determination of the transaction price; • Allocation of the transaction price to the performance obligations in the contract; and • Recognition of revenue when, or as, the Company satisfies a performance obligation. The Company identifies performance obligations in its contracts with customers, which primarily include subscription services and professional services. The transaction price is determined based on the amount to which the Company expects to be entitled to in exchange for providing the promised services to the customer. The transaction price in the contract is allocated to each distinct performance obligation on a relative standalone selling price basis. Revenue is recognized when performance obligations are satisfied. Contract payment terms are typically net 30 days. Collectability is assessed based on a number of factors including collection history and creditworthiness of the customer, and the Company may mitigate exposures to credit risk by requiring payments in advance. If collectability of substantially all consideration to which we are entitled under the contract is determined to be not probable, revenue is not recorded until collectability becomes probable at a later date. Revenue is recorded based on the transaction price excluding amounts collected on behalf of third parties, such as sales taxes, which are collected on behalf of, and remitted to, governmental authorities. Subscription and Returns Revenue Subscription and returns revenue primarily consists of contractually agreed upon fees paid for using the Company’s cloud-based solutions, which include tax determination and compliance management services, and fees paid for preparing and filing transaction tax returns on behalf of customers. Under the Company’s subscription agreements, customers select a price plan that includes an allotted maximum number of transactions over the subscription term. Unused transactions are not carried over to the customer’s next subscription term, and customers are not entitled to refunds of fees paid or relief from fees due in the event they do not use the allotted number of transactions. If customers exceed the maximum transaction level within their price plan, the Company will generally upgrade the customer to a higher transaction price plan or, in some cases, charge overage fees on a per transaction basis. The Company’s subscription arrangements do not provide the customer with the right to take possession of the software supporting the cloud-based application services. The Company’s standard subscription contracts are non-cancelable except where contract terms provide rights to cancel in the first 60 days of the contract term. Cancellations under the Company’s standard subscription contracts are not material, and do not have a significant impact on revenue recognized. Tax returns processing services include collection of tax data and amounts, preparation of compliance forms, and submission to taxing authorities. Returns processing services are primarily charged on a subscription basis for an allotted number of returns to process within a given time period. Revenue is recognized ratably over the contractual term of the arrangement, beginning on the date that the service is made available to the customer. The Company invoices its subscription customers for the initial term at contract signing and at each subscription renewal. Initial terms generally range from 12 to 18 months, and renewal periods are typically one year. Amounts that are contractually billable and have been invoiced, or which have been collected as cash, are initially recorded as deferred revenue or contract liabilities. While most of the Company’s customers are invoiced once at the beginning of the term, a portion of customers are invoiced semi-annually, quarterly, or monthly. Included in the total subscription fee for cloud-based solutions are non-refundable upfront fees that are typically charged to the Company’s new customers. These fees are associated with work performed to set up a customer with the Company’s services, and do not represent a distinct good or service. Instead, the fees are included within the transaction price and allocated to the remaining performance obligations in the contract. The Company recognizes revenue for these fees in accordance with the revenue recognition for those performance obligations. Also included in subscription and returns revenue is interest income on funds held for customers. The Company uses trust accounts at FDIC-insured institutions to provide tax remittance services to customers and collect funds from customers in advance of remittance to tax authorities. After collection and prior to remittance, the Company earns interest on these funds. Professional Services Revenue The Company bills for service arrangements on a fixed fee, milestone, or time and materials basis. Professional services revenue includes fees from providing tax analysis, configurations, data migrations, integration, training, and other support services. The transaction price allocated to professional services performance obligations is recognized as revenue as services are performed or upon completion of work. Judgments and Estimates The Company’s contracts with customers often include obligations to provide multiple services to a customer. Determining whether services are considered distinct performance obligations that should be accounted for separately from one another requires judgment. Subscription services and professional services are both distinct performance obligations that are accounted for separately. Judgment is required to determine the standalone selling price (“SSP”) for each distinct performance obligation. The Company allocates revenue to each performance obligation based on the relative SSP. The Company determines SSP for performance obligations based on overall pricing objectives, which take into consideration observable prices, market conditions and entity-specific factors. This includes a review of historical data related to the services being sold and customer demographics. The Company uses a range of amounts to estimate SSP for performance obligations. There is typically more than one SSP for individual services due to the stratification of those services by information such as size and type of customer. The revenue recognition accounting policy for ASC 605 is included in the Annual Report on Form 10-K for the year ended December 31, 2018, which was filed with the SEC on February 28, 2019. The revenue recognition accounting policy for ASC 605 is applied to the disclosures in Note 6, which include amounts presented for 2019. There were no changes to the ASC 605 policy during the first quarter of 2019. Assets Recognized from the Costs to Obtain a Contract with a Customer The Company recognizes an asset for the incremental costs of obtaining a contract with a customer if it expects the benefit of those costs to be longer than one year. The Company has determined that certain costs related to employee sales incentive programs and partner commission programs represent incremental costs of obtaining a contract and therefore should be capitalized. Capitalized costs are included in deferred commissions on the consolidated balance sheets. These deferred commissions are amortized over an estimated period of benefit of generally six years. The Company determined the period of benefit by taking into consideration its past experience with customers, the expected life of acquired technology that generates revenue, industry peers, and other available information. The period of benefit is generally longer than the term of the initial contract because of anticipated renewals. The Company elected to apply the practical expedient to recognize the incremental costs of obtaining a contract as an expense if the amortization period of the asset would have been one year or less. Recently Adopted Accounting Standards As an “emerging growth company,” the Jumpstart Our Business Startups Act, or the JOBS Act, allows the Company to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. The Company has elected to use the adoption dates applicable to private companies. As a result, the Company’s consolidated financial statements may not be comparable to the financial statements of issuers who are required to comply with the effective date for new or revised accounting standards that are applicable to public companies. ASU No. 2014-09 In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09 which, along with subsequent ASUs, amends the existing accounting standards for revenue recognition, and is codified as ASC 606. This guidance is based on principles that govern the recognition of revenue at the amount an entity expects to be entitled to receive as services are provided to customers. The Company adopted the new revenue recognition standard in the first quarter of 2019 on a modified retrospective basis and applied the new revenue recognition standard only to contracts that were not completed contracts prior to January 1, 2019. The cumulative effect of the changes made to the consolidated January 1, 2019 balance sheet resulting from the adoption of ASC 606 was as follows (in thousands): Balance at December 31, 2018 Adjustments due to ASC 606 Balance at January 1, 2019 Assets Trade accounts receivable $ 40,287 $ (805 ) $ 39,482 Deferred commissions, current portion — 4,464 4,464 Deferred commissions, net of current portion — 14,803 14,803 Liabilities and shareholders' equity Accrued expenses 42,217 2,090 44,307 Deferred revenue, current portion 125,260 (3,157 ) 122,103 Deferred revenue, net of current portion 9,393 (8,093 ) 1,300 Accumulated deficit (487,602 ) 27,622 (459,980 ) The adoption changed the revenue recognition for non-refundable upfront fees included with new or upgraded subscriptions. Prior to the adoption of the new revenue recognition standard, the Company recognized revenue for these fees over the expected term of the customer relationship. Under the new guidance, the transaction price is allocated to distinct performance obligations. Because upfront fees do not represent a distinct performance obligation, any such fees will be recognized over the period in which distinct performance obligations in the contract are satisfied, which is typically the subscription term. The new revenue recognition standard also changed the determination of the contract term associated with subscriptions that were upgraded during the subscription term. Prior to the adoption of the new revenue recognition standard, additional fees associated with an upgraded subscription for services already delivered were recognized retrospectively upon upgrade. Under the new guidance, the fees related to the upgraded subscriptions are recognized prospectively over the contract term. The adoption also changed the revenue recognition for contracts that include non-standard, extended customer cancellation provisions. Under the new guidance, a contract only exists for the period of time in which a contract cannot be cancelled, which generally corresponds to the termination notice period. Prior to the adoption of the new revenue recognition standard, non-standard, extended cancellation provisions were not a factor in determining the term of a contract. To the extent cash is received for a contract that includes a non-standard, extended cancellation provision, deferred revenue is recognized only for the amount for which the Company has an enforceable right. A contract liability is established for the remaining amount. The new revenue recognition standard requires the Company to estimate variable consideration at contract inception as an increase or decrease to the transaction price. The total transaction price, inclusive of variable consideration, is allocated to performance obligations, or distinct service periods within a performance obligation, on a relative SSP basis and recognized as performance obligations are satisfied. Prior to the adoption of the new revenue recognition standard, overage fees, concessions, and cancellations allowed in the first 60 days of a standard subscription contract were recognized as they occurred. The new revenue recognition standard requires capitalization of certain incremental costs of obtaining a contract, such as certain employee sales commissions and partner commissions, which impacts the period in which the expense is recorded. Prior to the adoption of the new revenue recognition standard, those commission costs were expensed as incurred. Under the new revenue recognition standard, the Company is required to capitalize incremental costs of obtaining a contract and amortize them over the expected period of benefit, which is generally six years. This results in a deferral of sales commission and partner commission expense each period. For further discussion regarding the impacts of adopting the new revenue recognition standard, see Note 6. ASU No. 2016-15 In August 2016, the FASB issued ASU No. 2016-15, related to classification of certain cash receipts and payments. ASU No. 2016-15 is intended to add or clarify guidance on the classification of certain cash receipts and payments in the statement of cash flows and to eliminate the diversity in practice related to such classifications. The guidance in ASU No. 2016-15 is required for annual reporting periods beginning after December 15, 2018 for business entities that are not public, with early adoption permitted. The Company adopted the guidance on January 1, 2019. The adoption had no impact on the consolidated financial statements. ASU No. 2018-07 In June 2018, the FASB issued ASU No. 2018-07, related to stock compensation for nonemployee share-based awards. ASU No. 2018-07 expands the scope of Topic 718 – Compensation – Stock Compensation to include share-based payments issued to nonemployees, with certain exceptions, in order to align the accounting for employees and nonemployees. The guidance in ASU No. 2018-07 is required for annual reporting periods beginning after December 15, 2019 for business entities that are not public, with early adoption permitted. The Company adopted the guidance on January 1, 2019. The adoption had an immaterial impact on the consolidated financial statements. New Accounting Standards Not Yet Adopted ASU No. 2016-02 In February 2016, the FASB issued ASU No. 2016-02 which requires lessees to generally recognize most operating leases on the balance sheets but record expenses on the income statements in a manner similar to current accounting standards. The guidance is effective in 2020 for business entities that are not public with early adoption permitted. The Company is currently evaluating the impact this guidance will have on the Company’s consolidated financial statements. The Company currently expects that most operating lease commitments will be subject to the new standard and will be recognized as operating lease liabilities and right-of-use assets upon adoption. While the Company has not yet quantified the impact, these adjustments will increase total assets and total liabilities relative to such amounts reported prior to adoption. ASU No. 2018-15 In August 2018, the FASB issued ASU No. 2018-15, related to implementation costs incurred in a cloud computing arrangement that is a service contract. The guidance in ASU No. 2018-15 is required for annual reporting periods beginning after December 15, 2020, for business entities that are not public, with early adoption permitted. The Company is currently evaluating the impact this guidance will have on the Company’s consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Assets and liabilities measured at fair value on a recurring basis The following financial assets and liabilities are measured at fair value on a recurring basis. The fair values recognized in the accompanying consolidated balance sheets and the level within the fair value hierarchy in which the fair value measurements fall is as follows (in thousands): Fair Value Measurements Using Quoted Prices Significant in Active Other Significant Markets for Observable Unobservable Fair Identical Assets Inputs Inputs March 31, 2019 Value (Level 1) (Level 2) (Level 3) Money market funds $ 140,316 $ 140,316 $ $ Earnout related to acquisitions 5,952 5,952 Fair Value Measurements Using Quoted Prices Significant in Active Other Significant Markets for Observable Unobservable Fair Identical Assets Inputs Inputs December 31, 2018 Value (Level 1) (Level 2) (Level 3) Money market funds $ 138,483 $ 138,483 $ $ Earnout related to acquisitions — — Earnout Liability In connection with an acquisition accounted for as a business combination under ASC 805, earnout liabilities are recorded at estimated fair value on a recurring basis. Acquisitions accounted for as business combinations that occurred during the first quarter of 2019 are discussed in Note 5. The Company estimates the fair value of earnout liabilities for business combinations using the probability-weighted discounted cash flow and Monte Carlo simulations. As of March 31, 2019, the earnout liability associated with the 2019 acquisition of substantially all of the assets of Compli, Inc. (“Compli”) was valued utilizing a discount rate of 5.4%, and the earnout liability associated with the 2019 acquisition of substantially all of the assets of Indix Corporation (“Indix”) was valued utilizing discount rates ranging from 5.4% to 5.8%. Each 2019 acquisition was valued using a risk-free rate based on linear interpolated U.S. Treasury rates commensurate with the term of the earnout. As of December 31, 2018 and March 31, 2019, the earnout liability associated with the 2016 acquisition of Gyori was determined to be zero. Earnout liabilities are classified as Level 3 liabilities because the Company uses unobservable inputs to value them, reflecting its assessment of the assumptions market participants would use to value these liabilities. Changes in the fair value of earnout liabilities associated with business combinations are recorded as other (income) expense, net in the consolidated statements of operations. A reconciliation of the beginning and ending balances of recurring fair value measurements recognized in the accompanying consolidated balance sheets using significant unobservable (Level 3) inputs, is as follows (in thousands): March 31, December 31, 2019 2018 Earnout liability: Balance beginning of period $ — $ 380 Fair value of earnout liability originally recorded 5,952 — Total unrealized (gains) losses included in other income — (380 ) Balance end of period $ 5,952 $ — As of March 31, 2019, the fair value of the earnout liabilities recorded during the first quarter of 2019 did not materially change from the fair value that was originally recorded at the date of acquisition. Assets and liabilities measured at fair value on a non-recurring basis The Company’s non-financial assets and liabilities, which include goodwill, intangible assets, and long-lived assets, are not required to be measured at fair value on a recurring basis. There were no fair value measurements of these assets during the first quarter of 2019, except as discussed in Note 5.

Balance Sheet Detail

Balance Sheet Detail	3 Months Ended
	Mar. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Detail	4 . Balance Sheet Detail Property and equipment, net consisted of the following (in thousands): Useful March 31, December 31, Life (Years) 2019 2018 Computer equipment and software 3 $ 13,948 $ 12,904 Internally developed software 6 4,075 3,620 Furniture and fixtures 5 6,462 5,850 Office equipment 5 586 586 Leasehold improvements 1 to 10 27,108 26,788 52,179 49,748 Accumulated depreciation (18,360 ) (16,375 ) Property and equipment—net $ 33,819 $ 33,373 Depreciation expense was $2.0 million for the three months ended March 31, 2019 and $1.6 million for the three months ended March 31, 2018. Prepaid expenses and other current assets consisted of the following (in thousands): March 31, December 31, 2019 2018 Prepaid expenses $ 11,080 $ 9,578 Deferred financing costs 853 643 Deposits 115 325 Other 1,207 761 Total $ 13,255 $ 11,307 Accrued expenses consisted of the following (in thousands): March 31, December 31, 2019 2018 Accrued payroll and related taxes $ 5,359 $ 3,800 Accrued state, federal, and local taxes 1,902 1,827 Accrued bonus 3,252 10,766 Employee stock purchase plan contributions 1,990 6,473 Accrued sales commissions 3,504 6,889 Accrued partner commissions 6,105 5,535 Accrued earnout liabilities 5,980 116 Contract liabilities 4,208 — Accrued purchase price related to acquisitions 1,584 — Other 7,716 6,811 Total $ 41,600 $ 42,217 Contract liabilities represent amounts that are collected in advance of the satisfaction of performance obligations under the new revenue recognition standard. See Recently Adopted Accounting Standards Contract Liabilities

Acquisitions of Businesses

Acquisitions of Businesses	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Acquisitions of Businesses	5 . Acquisitions of Businesses January 2019 Acquisition of Compli On January 22, 2019, the Company completed the acquisition of substantially all of the assets of Compli under an Asset Purchase Agreement (the “Compli Purchase”). Compli is a provider of compliance services, technology, and software to producers, distributors, and importers of alcoholic beverages in the United States. The Company accounted for the Compli Purchase as a business combination. As a result of the acquisition, the Company expanded its ability to provide transaction tax solutions and content for the alcoholic beverage industry. The transaction costs associated with the acquisition were not material. The total consideration transferred related to this transaction was $17.1 million, consisting of $11.8 million paid in cash at closing, an additional $1.6 million of cash to be paid out after twelve months, and an earnout provision fair valued upon acquisition at $3.8 million. The earnout provision is for a one-time payment and has a maximum payout of $4.0 million based on revenue recognized by the Company from the acquired operating assets for the twelve-month period ending January 31, 2020. The earnout was originally recognized at fair value at the date of the business combination and is recorded as an accrued earnout liability in accrued expenses on the consolidated balance sheet as of March 31, 2019. The earnout is adjusted to fair value quarterly (see Note 3). Estimated fair values of the assets acquired and the liabilities assumed in the Compli Purchase as of the acquisition date are provided in the following table (in thousands): Assets acquired: Current assets $ 505 Developed technology, customer relationships, and other intangibles 4,288 Goodwill 12,807 Total assets acquired 17,600 Liabilities assumed: Current liabilities 482 Total liabilities assumed 482 Net assets acquired $ 17,118 The estimated fair values are preliminary in nature and subject to adjustments, which could be material. The Company is currently in the process of finalizing the valuations related to the acquired intangible assets and contingent consideration. The valuations will be finalized when certain information arranged to be obtained has been received and the Company’s review of that information has been completed. The Company utilizes different valuation approaches and methodologies to determine the fair value of acquired intangible assets. A summary of the valuation methodologies, significant assumptions, and estimated useful lives of acquired intangible assets in the Compli Purchase are provided in the below table (in thousands): Intangible Assigned Value Valuation Methodology Discount Rate Estimated Useful Life Customer relationships $ 3,250 Multi-period excess earnings-income approach 13 % 6 years Trademarks and trade names 32 Relief from royalty- income approach 13 % 2 years Developed technology and customer database 910 Relief from royalty- income approach 13 % 6 years Noncompetition agreements 96 With-and-without valuation- income approach 13 % 3 years The excess of the purchase price over the net identified tangible and intangible assets of $12.8 million has been recorded as goodwill, which includes synergies expected from the combined service offerings and the value of the assembled workforce. The goodwill is expected to be non-deductible for tax purposes. For the period from the date of the Compli acquisition through March 31, 2019, revenue was $0.8 million and pre-tax loss was $0.1 million from the Compli business. February 2019 Acquisition of Indix On February 6, 2019, the Company completed the acquisition of substantially all of the assets of Indix under an Asset Purchase Agreement (the “Indix Purchase”). Indix is an artificial intelligence company providing comprehensive product descriptions for more than one billion products sold and shipped worldwide. The Company accounted for the Indix Purchase as a business combination. As a result of the acquisition, the Company intends to use the Indix artificial intelligence to maintain and expand its tax content database. The transaction costs associated with the acquisition were not material. The total consideration transferred related to this transaction was $9.1 million, consisting of $5.5 million paid in cash at closing, an additional $1.4 million cash to be paid after eighteen months, and an earnout provision valued upon acquisition at $2.2 million. The earnout provision has a maximum payout of $3.0 million based on the successful transition and achievement of development milestones established in the purchase agreement. The earnout provides for payouts of $0.5 million within three months of closing, $0.65 million within seven months of closing, $0.65 million within eight months of closing, and $1.2 million within 12 months of closing. The earnout was originally recognized at fair value at the date of the business combination and is recorded in accrued expenses on the consolidated balance sheet. The earnout is adjusted to fair value quarterly (see Note 3). Estimated fair values of the assets acquired and the liabilities assumed in the Indix Purchase as of the acquisition date are provided in the following table (in thousands): Assets acquired: Current assets $ 94 Developed technology 4,472 Goodwill 4,953 Total assets acquired 9,519 Liabilities assumed: Current liabilities 392 Total liabilities assumed 392 Net assets acquired $ 9,127 These estimated fair values are preliminary in nature and subject to adjustments, which could be material. The Company is currently in the process of finalizing the valuations related to the acquired intangible assets and contingent consideration. The valuations will be finalized when certain information arranged to be obtained has been received and the Company’s review of that information has been completed. The Company utilizes different valuation approaches and methodologies to determine the fair value of acquired intangible assets. A summary of the valuation methodologies, significant assumptions, and estimated useful lives of acquired intangible assets in the Indix Purchase are provided in the below table (in thousands): Intangible Assigned Value Valuation Methodology Discount Rate Estimated Useful Life Developed technology $ 4,472 Relief from royalty- income approach 24.5% 6 years The excess of the purchase price over the net identified tangible and intangible assets of $5.0 million has been recorded as goodwill, which includes cost savings expected from the use of the acquired technology and the value of the assembled workforce. The goodwill is expected to be non-deductible for tax purposes. For the period from the date of the Indix acquisition through March 31, 2019, pre-tax loss was $0.7 million from the Indix business.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2019
Revenue From Contract With Customer [Abstract]
Revenue	6 . Revenue The Company adopted the new revenue recognition accounting standard ASC 606 effective January 1, 2019 on a modified retrospective basis and applied the new standard only to contracts that were not completed contracts prior to January 1, 2019. See Note 2 for a description of the Company’s ASC 606 revenue recognition accounting policy. Financial results for reporting periods during 2019 are presented in compliance with the new revenue recognition standard. Historical financial results for reporting periods prior to 2019 have not been retroactively restated and are presented in conformity with amounts previously disclosed under ASC 605. This note includes additional information regarding the impacts from the adoption of the new revenue recognition standard on the financial results for the three months ended March 31, 2019. This includes the presentation of financial results during 2019 under ASC 605 for comparison to the prior year. The revenue recognition accounting policy for ASC 605 is included in the Company's Annual Report on Form 10-K for the year ended December 31, 2018, which was filed with the SEC on February 28, 2019. There were no changes to the Company’s ASC 605 policy during the first quarter of 2019. Consolidated Balance Sheets – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated balance sheet as of March 31, 2019 (in thousands): March 31, December 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) (unaudited) (unaudited) (unaudited) Assets Current assets: Cash and cash equivalents $ 146,878 $ — $ 146,878 $ 142,322 Trade accounts receivable—net of allowance for doubtful accounts 45,381 919 46,300 40,287 Deferred commissions 6,062 (6,062 ) — — Prepaid expenses and other current assets 13,255 — 13,255 11,307 Total current assets before customer fund assets 211,576 (5,143 ) 206,433 193,916 Funds held from customers 19,365 — 19,365 13,113 Receivable from customers—net of allowance for doubtful accounts 1,238 — 1,238 270 Total current assets 232,179 (5,143 ) 227,036 207,299 Noncurrent assets: Property and equipment—net 33,819 — 33,819 33,373 Goodwill 78,842 — 78,842 61,300 Intangible assets—net 26,440 — 26,440 19,371 Deferred commissions 19,582 (19,582 ) — — Other noncurrent assets 1,824 — 1,824 1,589 Total assets $ 392,686 $ (24,725 ) $ 367,961 $ 322,932 Liabilities and shareholders' equity Current liabilities: Trade payables $ 9,536 $ — $ 9,536 $ 4,847 Accrued expenses 41,600 (4,208 ) 37,392 42,217 Deferred revenue 131,733 4,951 136,684 125,260 Total current liabilities before customer fund obligations 182,869 743 183,612 172,324 Customer fund obligations 20,502 — 20,502 13,349 Total current liabilities 203,371 743 204,114 185,673 Noncurrent liabilities: Deferred revenue 981 8,499 9,480 9,393 Deferred tax liability 599 — 599 560 Deferred rent 16,927 — 16,927 17,317 Other noncurrent liabilities 1,835 — 1,835 436 Total liabilities 223,713 9,242 232,955 213,379 Commitments and contingencies Shareholders' equity: Preferred stock — — — — Common stock 7 — 7 7 Additional paid-in capital 640,996 — 640,996 599,493 Accumulated other comprehensive income (loss) (2,807 ) — (2,807 ) (2,345 ) Accumulated deficit (469,223 ) (33,967 ) (503,190 ) (487,602 ) Total shareholders’ equity 168,973 (33,967 ) 135,006 109,553 Total liabilities and shareholders' equity $ 392,686 $ (24,725 ) $ 367,961 $ 322,932 Consolidated Statements of Operations (Unaudited) – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated statement of operations for the three months ended March 31, 2019 (in thousands, except per share amounts): For the Three Months Ended March 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) Revenue: Subscription and returns $ 78,231 $ 84 $ 78,315 $ 57,870 Professional services 6,739 (53 ) 6,686 3,507 Total revenue 84,970 31 85,001 61,377 Cost of revenue: Subscription and returns 20,978 — 20,978 14,817 Professional services 4,329 — 4,329 2,692 Total cost of revenue 25,307 — 25,307 17,509 Gross profit 59,663 31 59,694 43,868 Operating expenses: Research and development 15,956 — 15,956 12,619 Sales and marketing 38,208 6,376 44,584 37,307 General and administrative 15,234 — 15,234 9,211 Total operating expenses 69,398 6,376 75,774 59,137 Operating loss (9,735 ) (6,345 ) (16,080 ) (15,269 ) Other (income) expense: Interest income (767 ) — (767 ) (36 ) Interest expense 111 — 111 894 Other (income) expense, net 48 — 48 (30 ) Total other (income) expense, net (608 ) — (608 ) 828 Loss before income taxes (9,127 ) (6,345 ) (15,472 ) (16,097 ) Provision for (benefit from) income taxes 116 — 116 (848 ) Net loss $ (9,243 ) $ (6,345 ) $ (15,588 ) $ (15,249 ) Net loss per share attributable to common shareholders, basic and diluted $ (0.14 ) $ (0.09 ) $ (0.23 ) $ (2.47 ) Weighted average shares of common stock outstanding, basic and diluted 68,381 — 68,381 6,170 Consolidated Statements of Comprehensive Loss (Unaudited) – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated statement of comprehensive loss for the three months ended March 31, 2019 (in thousands): For the Three Months Ended March 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) Net loss $ (9,243 ) $ (6,345 ) $ (15,588 ) $ (15,249 ) Other comprehensive income (loss)—Foreign currency translation (462 ) — (462 ) 603 Total comprehensive loss $ (9,705 ) $ (6,345 ) $ (16,050 ) $ (14,646 ) Consolidated Statements of Cash Flows (Unaudited) – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated statement of cash flows for the three months ended March 31, 2019 (in thousands): For the Three Months Ended March 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) Cash flows from operating activities: Net loss $ (9,243 ) $ (6,345 ) $ (15,588 ) $ (15,249 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 3,681 — 3,681 2,990 Stock-based compensation 6,560 — 6,560 3,510 Deferred tax expense 39 — 39 (1,018 ) Amortization of deferred rent (133 ) — (133 ) 301 Non-cash change in earnout liability — — — (71 ) Non-cash bad debt expense 222 — 222 67 Other 58 — 58 180 Changes in operating assets and liabilities: Trade accounts receivable (5,535 ) (114 ) (5,649 ) (6,428 ) Prepaid expenses and other current assets (1,705 ) — (1,705 ) (1,907 ) Other long-term assets (236 ) — (236 ) 110 Trade payables 3,590 — 3,590 (1,736 ) Accrued expenses and other current liabilities (10,373 ) (2,118 ) (12,491 ) (5,771 ) Deferred commissions (6,377 ) 6,377 — — Deferred revenue 9,031 2,200 11,231 11,647 Net cash used in operating activities (10,421 ) — (10,421 ) (13,375 ) Cash flows from investing activities: Net increase in customer fund assets (7,224 ) — (7,224 ) (18,527 ) Cash paid for acquired intangible assets (131 ) — (131 ) — Cash paid for acquisitions of businesses (17,310 ) — (17,310 ) — Purchase of property and equipment (2,114 ) — (2,114 ) (3,625 ) Net cash used in investing activities (26,779 ) — (26,779 ) (22,152 ) Cash flows from financing activities: Proceeds from credit facility — — — 18,000 Payments of deferred financing costs (39 ) — (39 ) — Net increase in customer fund obligations 7,143 — 7,143 18,527 Proceeds from exercise of stock options and common stock warrants 27,311 — 27,311 326 Proceeds from purchases of stock under employee stock purchase plan 7,664 — 7,664 — Taxes paid related to net share settlement of stock-based awards (93 ) — (93 ) (2,016 ) Repurchase of shares — — — (819 ) Net cash provided by financing activities 41,986 — 41,986 34,018 Foreign currency effect on cash and cash equivalents (230 ) (230 ) 56 Net change in cash and cash equivalents 4,556 — 4,556 (1,453 ) Cash and cash equivalents—Beginning of period 142,322 — 142,322 14,075 Cash and cash equivalents—End of period $ 146,878 $ — $ 146,878 $ 12,622 Disaggregation of Revenue The following table disaggregates revenue generated within the United States (U.S.) from revenue generated from customers outside of the U.S. Revenue for transaction tax compliance in the U.S. is further disaggregated based on the solutions or services purchased by customers. Total revenues consisted of the following (in thousands): For the Three Months Ended March 31, 2019 2018 Revenue (U.S.): Subscription and returns Tax determination $ 45,232 $ 33,150 Tax returns and compliance management 26,686 21,800 Interest income on funds held for customers 729 — Total subscription and returns 72,647 54,950 Professional services 5,735 2,967 Total revenue (U.S.) 78,382 57,917 Total revenue (non-U.S.) 6,588 3,460 Total revenue $ 84,970 $ 61,377 Disclosures Related to Contracts with Customers Timing may differ between the satisfaction of performance obligations and the invoicing and collection of amounts related to contracts with customers. Liabilities are recorded for amounts that are collected in advance of the satisfaction of performance obligations. To the extent a contract exists, as defined by ASC 606, these liabilities are classified as current and non-current deferred revenue. To the extent that a contract does not exist, these liabilities are classified as contract liabilities. Contract liabilities are transferred to deferred revenue at the point in time when the criteria that establish the existence of a contract are met. Contract Liabilities A summary of the activity impacting the contract liabilities during the three months ended March 31, 2019 is presented below (in thousands): Contract Liabilities Balance at December 31, 2018 $ — Adoption of ASC 606 2,090 Contract liabilities transferred to deferred revenue (1,257 ) Addition to contract liabilities 3,375 Balance at March 31, 2019 $ 4,208 As of March 31, 2019, contract liabilities are expected to be transferred to deferred revenue within the next 12 months and therefore are included in accrued expenses on the consolidated balance sheets. Deferred Revenue A summary of the activity impacting deferred revenue balances during the three months ended March 31, 2019 is presented below (in thousands): Deferred Revenue Balance at December 31, 2018 $ 134,653 Adoption of ASC 606 (11,250 ) Revenue recognized (84,970 ) Additional amounts deferred 94,281 Balance at March 31, 2019 $ 132,714 Assets Recognized from the Costs to Obtain Contracts with Customers Assets are recognized for the incremental costs of obtaining a contract with a customer if the benefit of those costs is expected to be longer than one year. These deferred commissions are amortized over an expected period of benefit of generally six years. A summary of the activity impacting the deferred commissions during the three months ended March 31, 2019 is presented below (in thousands): Deferred Commissions Balance at December 31, 2018 $ — Adoption of ASC 606 19,267 Additional commissions deferred 7,656 Amortization of deferred commissions (1,279 ) Balance at March 31, 2019 $ 25,644 As of March 31, 2019, $6.1 million of deferred commissions are expected to be amortized within the next 12 months and therefore are included in current assets on the consolidated balance sheets. The remaining amount of deferred commissions are included in noncurrent assets. There were no impairments of assets related to deferred commissions during the three months ended March 31, 2019. There were no assets recognized related to the costs to fulfill contracts during the three months ended March 31, 2019 as these costs were not material. Remaining Performance Obligations Contracts with customers include amounts allocated to performance obligations that will be satisfied at a later date. These amounts include additional performance obligations that are not yet recorded in the consolidated balance sheets. As of March 31, 2019, amounts allocated to these additional contractual obligations are $32.2 million, of which $31.9 million is expected to be recognized as revenue over the next 12 months with the remaining amount thereafter.

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	7 . Intangible Assets Finite-lived intangible assets Finite-lived intangible assets consisted of the following (in thousands): March 31, 2019 Average Useful Life (Years) Gross Accumulated Amortization Net Customer relationships 3 to 10 $ 18,652 $ (9,694 ) $ 8,958 Developed technology 3 to 8 36,314 (18,976 ) 17,338 Noncompete agreements 3 to 5 669 (554 ) 115 Tradename and trademarks 1 to 4 452 (423 ) 29 $ 56,087 $ (29,647 ) $ 26,440 December 31, 2018 Average Useful Life (Years) Gross Accumulated Amortization Net Customer relationships 3 to 10 $ 15,412 $ (9,202 ) $ 6,210 Developed technology 3 to 8 30,935 (17,806 ) 13,129 Noncompete agreements 3 to 5 574 (542 ) 32 Tradename and trademarks 1 to 4 420 (420 ) — $ 47,341 $ (27,970 ) $ 19,371 Finite-lived intangible assets are generally amortized on a straight-line basis over the remaining estimated useful life as management believes this reflects the expected benefit to be received from these assets. Finite-lived intangible assets amortization expense was $1.7 million for the three months ended March 31, 2019 and $1.4 million for the three months ended March 31, 2018. Acquisitions of finite-lived intangible assets In May 2018, the Company acquired developed technology to facilitate cross-border transactions (e.g., tariffs and duties), from Tradestream Technologies Inc. and Wise 24 Inc. (the “Sellers”) for cash and common stock. Total consideration for the purchase includes an earnout computed on future revenue and billings recognized by the Company over the six years following the acquisition, up to a maximum of $30.0 million. The earnout is payable in cash and common stock at the end of each six-month measurement period ending on June 30 or December 31 through 2023. The cash portion of the earnout is computed based on eligible billings in the measurement period. The number of shares of common stock to be issued is computed based on the eligible revenue recognized in the measurement period divided by the average closing price of the Company’s common stock during the last ten days of the measurement period. As earnout payments become due, those costs will be capitalized as part of the developed technology asset and amortized over the remaining useful life. During the first quarter of 2019, the Company paid $0.1 million and issued 1,634 shares of common stock to the Sellers for the first earnout measurement period ended December 31, 2018. Goodwill Changes in the carrying amount of goodwill through March 31, 2019 are summarized as follows (in thousands): Balance—December 31, 2018 $ 61,300 Acquisition of Compli 12,807 Acquisition of Indix 4,953 Cumulative translation adjustments (218 ) Balance—March 31, 2019 $ 78,842 Goodwill is tested for impairment annually on October 31 at the reporting unit level or whenever circumstances occur indicating goodwill might be impaired. The impairment test involves comparing the fair value of each reporting unit to its carrying value, including goodwill. Fair value reflects the price a market participant would be willing to pay in a potential sale of the reporting unit. If the fair value exceeds carrying value, the Company will conclude that no goodwill impairment has occurred. If the carrying value of the reporting unit exceeds its fair value, the Company will recognize an impairment loss in an amount equal to the excess, not to exceed the carrying value. The Company has three reporting units for goodwill impairment testing consisting of its U.S., European, and Brazilian operations. As of March 31, 2019, the Brazilian reporting unit had no associated goodwill.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8 . Commitments and Contingencies Leases Rent expense was $3.0 million for the three months ended March 31, 2019 and $2.3 million for the three months ended March 31, 2018. Sublease income was $0.4 million for the three months ended March 31, 2019 with no sublease income for the three months ended March 31, 2018. Contingencies Loss contingencies may arise in connection with the ordinary conduct of the Company’s business activities. The Company considers all loss contingencies on a quarterly basis and based on known facts assesses whether potential losses are considered reasonably possible, probable, and estimable. The Company establishes an accrual for loss contingencies when the loss is both probable and reasonably estimable. These accruals represent management’s best estimate of probable losses and, in such cases, there may be an exposure to loss in excess of the amounts accrued. Significant judgment is required to determine both likelihood of there being a probable loss and the estimated amount of a loss. If a loss contingency is not both probable and reasonably estimable, the Company does not establish an accrual, but will evaluate other disclosure requirements and continue to monitor the matter for developments that would make the loss contingency both probable and reasonably estimable. The ultimate outcome of any litigation relating to a loss contingency is uncertain and, regardless of outcome, litigation can have an adverse impact on the Company because of defense costs, negative publicity, diversion of management resources, and other factors. In its standard subscription agreements, the Company has agreed to indemnification provisions with respect to certain matters. Further, from time to time, the Company has also assumed indemnification obligations through its acquisition activity. These indemnification provisions can create a liability to the Company if its services do not appropriately calculate taxes due to tax jurisdictions, or if the Company is delinquent in the filing of returns on behalf of its customers. Although the Company’s agreements have disclaimers of warranties that limit its liability (beyond the amounts the Company agrees to pay pursuant to its indemnification obligations and guarantees, as applicable), a court could determine that such disclaimers and limitations are unenforceable as a matter of law and hold the Company liable for certain errors. Further, in some instances the Company has negotiated agreements with specific customers or assumed agreements in connection with the Company’s acquisitions that do not limit this liability or disclaim these warranties. Except as discussed below, it is not possible to reasonably estimate the potential loss under these indemnification arrangements. While the Company has never paid a material claim related to these indemnification provisions, the Company believes that, as of March 31, 2019, there is a reasonable possibility that a loss may be incurred pursuant to certain of these arrangements and estimates a range of loss of up to On October 22, 2018, PTP OneClick, LLC (“PTP”) filed a lawsuit against Avalara, Inc. in the United States District Court for the Eastern District of Wisconsin. The lawsuit alleges that making, using, offering to sell, and selling AvaTax, Avalara Returns, and TrustFile (the “Avalara Products”) infringe U.S. Patent No. 9,760,915 held by PTP and also alleges unspecified trade secret misappropriation, unfair competition, and breach of contract. PTP seeks judgments of willful patent infringement, willful trade secret misappropriation, unfair competition, and breach of contract. PTP requests preliminary and permanent injunctions to enjoin the Company from making, using, offering to sell, and selling the Avalara Products along with treble damages and attorneys’ fees. Based upon the Company’s review of the complaint and the specified patent, the Company believes that the Company has meritorious defenses to PTP’s claims. On November 7, 2018, the Company moved to dismiss the lawsuit and to have the patent held invalid, and also moved to transfer the matter to the United States District Court located in Seattle, Washington. On April 30, 2019, the United States District Court for the Eastern District of Wisconsin granted the Company’s motion to transfer, reserving resolution of the motion to dismiss for the United States District Court for the Western District of Washington. The Company intends to continue to vigorously defend against PTP’s allegations.

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	9 . Debt Loan and Security Agreement The Company has a loan and security agreement with Silicon Valley Bank and Ally Bank (the “Lenders”) that consists of a $50.0 million revolving credit facility (the “Credit Facility”), which is subject to a borrowing base limitation, is reduced by outstanding letters of credit, and must be repaid in November 2019. The obligations under the Credit Facility are collateralized by substantially all the assets of the Company, including intellectual property, receivables and other tangible and intangible assets. The Credit Facility includes several affirmative and negative covenants, including a requirement that the Company maintain minimum net billings and minimum liquidity and observe restrictions on dispositions of property, changes in its business, mergers or acquisitions, incurring indebtedness, and distributions or investments. Written consent of the Lenders is required to pay dividends to shareholders, with the exception of dividends payable in common stock. As of March 31, 2019, the Company was in compliance with all covenants of the Credit Facility. The Company is required to pay a quarterly fee of 0.50% per annum on the undrawn portion available under the revolving credit facility plus the sum of outstanding letters of credit. Under the Credit Facility, the interest rate on the revolving credit facility is based on the greater of either 4.25% or the current prime rate, plus 1.75%. As of March 31, 2019, the Company had no borrowings outstanding under the Credit Facility.

Convertible Preferred Stock and

Convertible Preferred Stock and Shareholders' Equity	3 Months Ended
	Mar. 31, 2019
Stockholders Equity Note [Abstract]
Convertible Preferred Stock and Shareholders' Equity	10 . Convertible Preferred Stock and Shareholders’ Equity Authorized Capital – Common Stock and Preferred Stock On June 15, 2018, the Company completed an initial public offering (“IPO”) listing its common stock on the New York Stock Exchange. The Company is authorized to issue two classes of stock designated as common stock and preferred stock. In June 2018, immediately following the IPO, the Amended and Restated Articles of Incorporation became effective, which increased authorized capital stock from 260,290,986 shares, consisting of 153,944,895 shares of common stock, $0.0001 par value per share, and 106,346,091 shares of convertible preferred stock, $0.0001 par value per share, to authorized capital stock of 620,000,000 shares, consisting of 600,000,000 shares of common stock, $0.0001 par value per share, and 20,000,000 shares of undesignated preferred stock, $0.0001 par value per share. There were no changes to the rights and preferences of the common stock as a result of the IPO. The changes to the Company’s shareholders’ equity for the three months ended March 31, 2019 is as follows (in thousands, except per share data): Accumulated Additional Other Total Common Stock Paid-In Comprehensive Accumulated Shareholders’ Shares Amount Capital Income (Loss) Deficit Equity Balance at January 1, 2019 66,768,563 $ 7 $ 599,493 $ (2,345 ) $ (487,602 ) $ 109,553 Impact of adoption of new accounting pronouncements (see Note 2) 27,622 27,622 Exercise of stock options 2,763,291 27,311 27,311 Shares tendered for cashless redemption of stock options (2,805 ) (93 ) (93 ) Stock-based compensation cost 6,571 6,571 Shares issued under employee stock purchase plan 372,764 7,664 7,664 Shares issued to purchase intangible assets 1,634 50 50 Loss on translation adjustment (462 ) (462 ) Net loss (9,243 ) (9,243 ) Balance at March 31, 2019 69,903,447 $ 7 $ 640,996 $ (2,807 ) $ (469,223 ) $ 168,973 The changes to the Company’s convertible preferred stock and shareholders’ equity (deficit) for the three months ended March 31, 2018 is as follows (in thousands, except per share data): Accumulated Convertible Additional Other Total Preferred Stock Common Stock Paid-In Comprehensive Accumulated Shareholders’ Shares Amount Shares Amount Capital Income (Loss) Deficit Deficit Balance at January 1, 2018 101,786,205 $ 370,921 5,992,293 $ 1 $ 18,121 $ 338 $ (412,052 ) $ (393,592 ) Exercise of stock options 785,991 6,025 6,025 Shares tendered for cashless redemption of stock options (465,710 ) (7,715 ) (7,715 ) Stock-based compensation cost 3,517 3,517 Repurchase of shares (10,000 ) (67 ) (48,152 ) (752 ) (752 ) Gain on translation adjustment 603 603 Net loss (15,249 ) (15,249 ) Balance at March 31, 2018 101,776,205 $ 370,854 6,264,422 $ 1 $ 19,196 $ 941 $ (427,301 ) $ (407,163 ) During the three months ended March 31, 2018, the Company repurchased shares from employees and non-employee investors at fair value for $0.8 million. All outstanding shares of convertible preferred stock were converted to common stock in connection with the Company’s IPO in June 2018. Common Stock Warrants Common stock warrants were granted to the Company’s Board of Directors for services provided. No common stock warrants were issued during the three months ended March 31, 2019. During the three months ended March 31, 2018, the Company issued 80,000 common stock warrants with a weighted average exercise price of $16.60 per share. The warrants granted to the Company’s Board of Directors in the first quarter of 2018 had a grant date fair value of $0.5 million, which was recorded as general and administrative expense. During 2018 and prior to the completion of the IPO, 363,000

Equity Incentive Plans

Equity Incentive Plans	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity Incentive Plans	1 1 . Equity Incentive Plans The Company has stock-based compensation plans that provide for the award of equity incentives, including stock options, stock awards, and restricted stock units (“RSUs”). As of March 31, 2019, the Company had stock options outstanding under the 2018 Equity Incentive Plan (the “2018 Plan”) and the 2006 Equity Incentive Plan (the “2006 Plan”), and had RSUs outstanding under the 2018 Plan. As of March 31, 2019, the Company also has an employee stock purchase plan. In April 2018, the 2018 Plan became effective in connection with the Company’s IPO. The 2018 Plan allows the Company to grant equity incentives to employees, directors, advisors, and consultants providing services to the Company. The total number of shares of common stock reserved for issuance under the 2018 Plan is equal to (1) 5,315,780 st Prior to the 2018 Plan, the Company awarded stock options under the 2006 Plan. The 2006 Plan was terminated in connection with the Company’s IPO. Outstanding awards under the 2006 Plan continue to be subject to the terms and conditions of the 2006 Plan. As of March 31, 2019, there were 8,039,077 shares subject to outstanding stock options under the 2006 Plan. Stock-Based Compensation The Company recognized total stock-based compensation cost related to equity incentive awards as follows (in thousands): For the Three Months Ended March 31, 2019 2018 Stock-based compensation cost: Common stock warrants $ — $ 512 Stock options 3,917 3,005 Restricted stock units 1,698 — Employee stock purchase plan 956 — Total stock-based compensation cost $ 6,571 $ 3,517 A small portion of stock-based compensation cost above is capitalized in accordance with the accounting guidance for internal-use software. The Company uses the straight-line attribution method for recognizing stock-based compensation expense. Stock Options The following table summarizes stock option activity for the Company’s stock-based compensation plans for the three months ended March 31, 2019: Weighted Weighted Average Aggregate Average Remaining Intrinsic Exercise Contractual Value Shares Price Life (Years) (in thousands) Options outstanding as of December 31, 2018 11,094,070 $ 12.17 6.81 $ 210,523 Options granted 801,002 41.41 Options exercised (2,763,291 ) 9.89 Options cancelled or expired (101,202 ) 14.96 Options outstanding as of March 31, 2019 9,030,579 15.44 7.10 364,420 Options exercisable as of March 31, 2019 4,744,344 $ 9.54 5.66 $ 219,420 A summary of options outstanding and vested as of March 31, 2019 is as follows: Options Outstanding Options Vested and Exercisable Exercise Number Weighted Average Number Vested Weighted Average Prices Outstanding Life (in Years) and Exercisable Life (in Years) $0.96 to $1.90 706,971 1.95 706,971 1.95 2.86 to 6.40 859,450 4.02 859,450 4.02 8.04 to 11.72 702,499 4.95 702,499 4.95 12.20 to 15.06 3,444,812 7.39 2,000,706 7.18 16.06 to 24.00 2,325,345 8.87 471,594 8.80 31.99 to 55.79 991,502 9.76 3,124 9.78 9,030,579 4,744,344 The total intrinsic value of options exercised during the three months ended March 31, 2019 and 2018 was $109.5 million and $7.0 million, respectively. The weighted average grant date fair value of options granted during the three months ended March 31, 2019 and 2018 was $17.93 and $7.16 As of March 31, 2019, $37.5 million of total unrecognized compensation cost related to stock options was expected to be recognized over a period of approximately three years. All stock-based payments to employees are measured based on the grant date fair value of the awards and recognized in the consolidated statements of operations over the period during which the employee is required to perform services in exchange for the award, generally a four-year, straight-line vesting period. For the options granted during the periods presented, the fair value of options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Three Months Ended March 31, 2019 2018 Fair market value of common stock $39.76 - 55.79 $16.86 Volatility 40% 40% Expected term 6 years 6 years Expected dividend yield n/a n/a Risk-free interest rate 2.31% - 2.65% 2.55% The Board of Directors intends all options granted to be exercisable at a price per share not less than the per share fair market value of the Company’s common stock underlying those options on the date of grant. Following the closing of the IPO, the fair market value per share of the Company’s common stock for purposes of determining stock-based compensation is the closing price of the Company’s common stock as reported on the applicable grant date. Prior to the IPO, the fair value of the common stock underlying stock options and common stock warrants was estimated by the Board of Directors, with input from management and third-party valuation firms. The enterprise value utilized in determining the fair value of common stock for financial reporting purposes was estimated using the market approach and the income approach. Under the market approach, the Company used the guideline public company method, which estimates the fair value of the business enterprise based on market prices of stock of guideline public companies and the option pricing method. Indications of value were estimated by utilizing revenue multiples to measure enterprise value. The guideline merged and acquired company method was not utilized in the valuation, as the Company regarded the method as less reliable as management believed it did not directly reflect the Company’s future prospects. The income approach estimated the enterprise value based on the present value of the Company’s future estimated cash flows and the residual value beyond the forecast period. The residual value was based on an exit (or terminal) multiple observed in the comparable company method analysis. The future cash flows and residual value were discounted to their present value to reflect the risks inherent in the Company achieving these estimated cash flows. The discount rate was based on venture capital rates of return for companies nearing an initial public offering. The discount rate was applied using the mid-year convention. The mid-year convention assumes that cash flows are generated evenly throughout the year, as opposed to in a lump sum at the end of the year. The Company lacks sufficient historical data on the volatility of its stock price. Selected volatility is representative of expected future volatility and was based on the historical and implied volatility of comparable publicly traded companies over a similar expected term. The expected term represents the period that the Company’s stock-based awards are expected to be outstanding. Given the Company’s relative inexperience of significant exercise activity, the expected term assumptions were determined based on application of the simplified method of expected term calculation by averaging the contractual life of option grants and the vesting period of such grants. This application, when coupled with the contractual life of 10 years and average vesting term of 4 years, creates an expected term of 6 years. The Company has not paid and does not expect to pay dividends. The risk-free interest rate was based on the rate for a U.S. Treasury zero-coupon issue with a term that closely approximates the expected term of the option grant at the date nearest the option grant date. Restricted Stock Units The following table summarizes RSU activity for the Company’s stock-based compensation plans for the three months ended March 31, 2019: Weighted Average Grant Date Fair Restricted Stock Units Value Per Share RSUs outstanding as of December 31, 2018 74,424 $ 32.69 RSUs granted 955,753 42.68 RSUs vested — RSUs cancelled (11,852 ) 39.76 RSUs outstanding as of March 31, 2019 1,018,325 $ 41.98 Stock-based compensation cost is recorded on a straight-line basis over the vesting term of each RSU grant, which is generally four years, based on the fair value of the Company’s underlying common stock on the date of grant. As of March 31, 2019, $41.0 million of total unrecognized compensation cost related to RSUs was expected to be recognized over a period of approximately four years. 2018 Employee Stock Purchase Plan The ESPP became effective on June 15, 2018, the first trading day of the Company’s common stock. The ESPP is intended to qualify as an employee stock purchase plan under Section 423 of the Internal Revenue Code of 1986, as amended. Purchases will be accomplished through participation in discrete offering periods. The first offering period began on June 15, 2018 and ended on January 31, 2019. Subsequent offering periods begin on August 1 and February 1 (or such other date determined by our Board of Directors or our Compensation and Leadership Development Committee). Eligible employees can select a rate of payroll deduction for purchases under the ESPP of between 1% and 15% of their eligible compensation. The purchase price for shares of common stock purchased under the ESPP is 85% of the lesser of the fair market value of the Company’s common stock on (i) the first day of the applicable offering period or (ii) the last day of the purchase period in the applicable offering period. The Company initially reserved 996,709 shares of common stock for sale under the ESPP. The aggregate number of shares reserved for sale under the ESPP increases automatically on each January 1, beginning January 1, 2019, by the number of shares equal to the least of (i) 1,000,000 shares of common stock, (ii) 1% of the aggregate number of shares of common stock outstanding on December 31 st As of March 31, 2019, there was approximately $1.1 million During the three months ended March 31, 2019, 372,764 shares of common stock were purchased under the ESPP. The grant date fair value of ESPP purchase rights issued during the first quarter of 2019 was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Three Months Ended March 31, 2019 Fair market value of common stock $40.60 Volatility 40% Expected term 0.5 years Expected dividend yield n/a Risk-free interest rate 2.59%

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	1 2 . Income Taxes The Company used an annual effective tax rate approach to calculate income taxes for the three months ended March 31, 2019 and 2018. The annual effective tax rate differs from the U.S. Federal statutory rate due primarily to providing a valuation allowance on deferred tax assets. Income taxes for international operations were not material for the three months ended March 31, 2019 and 2018. The effective income tax rate was an expense of 1.3% for the three months ended March 31, 2019,

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Shareholders	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Shareholders	1 3 . Net Loss Per Share Attributable to Common Shareholders The Company calculates basic and diluted net loss per share attributable to common shareholders in conformity with the two-class method required for companies with participating securities. Prior to the IPO, the Company considered all series of convertible preferred stock to be participating securities. Under the two-class method, the net loss attributable to common shareholders was not allocated to the convertible preferred stock as the holders of convertible preferred stock did not have a contractual obligation to share in losses. The diluted net loss per share attributable to common shareholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, all common stock equivalents have been excluded from the calculation of diluted net loss per share attributable to common shareholders as their effect is antidilutive. As a result, basic and diluted net loss per common share was the same for each period presented. The following table sets forth the computation of basic and diluted net loss per common share (in thousands, except per share amounts): For the Three Months Ended March 31, 2019 2018 Numerator: Net loss attributable to common shareholders $ (9,243 ) $ (15,249 ) Denominator: Weighted-average common shares outstanding-basic 68,381 6,170 Dilutive effect of share equivalents resulting from stock options, restricted stock units, common stock warrants, and convertible preferred shares (as converted) — — Weighted-average common shares outstanding-diluted 68,381 6,170 Net loss per common share, basic and diluted $ (0.14 ) $ (2.47 ) The following weighted-average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common shareholders for the periods presented because the impact of including them would have been antidilutive (in thousands): For the Three Months Ended March 31, 2019 2018 Options to purchase common shares 10,237 11,286 Unvested restricted stock units 631 — Employee stock purchase plan shares 14 — Common stock warrants — 549 Convertible preferred shares (as converted) — 50,889 Total 10,882 62,724

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Interim Financial Information	Interim Financial Information The accompanying consolidated financial statements were prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Certain information and disclosures normally included in consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. Accordingly, these consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes for the year ended December 31, 2018, included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on February 28, 2019. The accompanying interim consolidated balance sheet as of March 31, 2019, the consolidated interim statements of operations for the three months ended March 31, 2019 and 2018, the consolidated statements of comprehensive loss for the three months ended March 31, 2019 and 2018, and the consolidated statements of cash flows for the three months ended March 31, 2019 and 2018, are unaudited. The unaudited interim consolidated financial statements have been prepared on a basis consistent with that used to prepare the audited annual consolidated financial statements and include, in the opinion of management, all adjustments, consisting of normal and recurring items, necessary for the fair presentation of the consolidated financial statements. The operating results for the three months ended March 31, 2019 are not necessarily indicative of the results expected for the full year ending December 31, 2019. The Company adopted the new revenue recognition accounting standard, Accounting Standards Codification (“ASC”) 606, effective January 1, 2019 on a modified retrospective basis (see Recently Adopted Accounting Standards
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions.
Segments	Segments The Company operates its business as one operating segment. Operating segments are defined as components of an enterprise about which separate financial information is evaluated regularly by the chief operating decision maker, the Company’s Chief Executive Officer, in deciding how to allocate resources and assess performance. The Company’s chief operating decision maker allocates resources and assesses performance based upon discrete financial information at the consolidated level.
Use of Estimates	Use of Estimates The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could materially differ from those estimates.
Fair Value Measurements	Fair Value Measurements The Company applies the fair value measurement and disclosure provisions of the Accounting Standards Codification. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy prioritizes the inputs used to measure fair value. The hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1 : Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 : Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Level 3 : Inputs are unobservable inputs based on the Company’s assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. The Company’s assessment of the significance of an input to the fair value measurement requires judgment, which may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash equivalents, trade accounts receivable, trade payables, and accrued expenses due to their short-term nature. The carrying amount of the Company’s revolving credit facility, to the extent there is a carrying amount as of the balance sheet date, approximates fair value, considering the interest rate is based on the prime interest rate.
Long-Lived Assets	Long-Lived Assets The Company evaluates long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. An impairment is recognized in the event the carrying value of such assets is not recoverable. If the carrying value is not recoverable, the fair value is determined and an impairment is recognized for the amount by which the carrying value exceeds the fair value. No impairment of long-lived assets occurred in the first quarter of 2019.
Income Taxes	Income Taxes The Company’s deferred tax assets and liabilities are determined based on temporary differences between the financial reporting and income tax basis of assets and liabilities and are measured using the enacted tax rates expected to apply in the years when the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that some of the deferred tax assets will not be realized. The Company assesses its income tax positions and records income taxes based upon management’s evaluation of the facts, circumstances, and information available at the reporting date. The Company determines whether its uncertain tax positions are more likely than not to be sustained upon examination based on the technical merits of the position. For tax positions not meeting the more likely than not threshold, the tax amount recognized in the consolidated financial statements is reduced by the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation by calculating the fair value of each option, common stock warrant, restricted stock unit (“RSU”), or purchase right issued under the Company’s 2018 Employee Stock Purchase Plan (“ESPP”) at the date of grant. The fair value of stock options, common stock warrants, and purchase rights issued under the ESPP is estimated by applying the Black-Scholes option-pricing model. This model uses the fair value of the Company’s underlying common stock at the measurement date, the expected or contractual term of the option, warrant or right, the expected volatility of its common stock, risk-free interest rates, and expected dividend yield of its common stock. The fair value of an RSU is determined using the fair value of the Company’s underlying common stock on the date of grant.
Revenue Recognition - ASC 606	Revenue Recognition – ASC 606 The Company primarily generates revenue from fees paid for subscriptions to tax compliance solutions and fees paid for services performed in preparing and filing tax returns on behalf of its customers. Amounts that have been invoiced are recorded in trade accounts receivable and deferred revenue, contract liabilities, or revenue, depending upon whether the revenue recognition criteria have been met. Revenue is recognized once the customer is provisioned and services are provided in an amount that reflects the consideration expected to be entitled to in exchange for those services. The Company’s revenue recognition policy follows guidance from ASC 606, Revenue from Contracts with Customers The Company determines revenue recognition through the following five-step framework: • Identification of the contract, or contracts, with a customer; • Identification of the performance obligations in the contract; • Determination of the transaction price; • Allocation of the transaction price to the performance obligations in the contract; and • Recognition of revenue when, or as, the Company satisfies a performance obligation. The Company identifies performance obligations in its contracts with customers, which primarily include subscription services and professional services. The transaction price is determined based on the amount to which the Company expects to be entitled to in exchange for providing the promised services to the customer. The transaction price in the contract is allocated to each distinct performance obligation on a relative standalone selling price basis. Revenue is recognized when performance obligations are satisfied. Contract payment terms are typically net 30 days. Collectability is assessed based on a number of factors including collection history and creditworthiness of the customer, and the Company may mitigate exposures to credit risk by requiring payments in advance. If collectability of substantially all consideration to which we are entitled under the contract is determined to be not probable, revenue is not recorded until collectability becomes probable at a later date. Revenue is recorded based on the transaction price excluding amounts collected on behalf of third parties, such as sales taxes, which are collected on behalf of, and remitted to, governmental authorities. Subscription and Returns Revenue Subscription and returns revenue primarily consists of contractually agreed upon fees paid for using the Company’s cloud-based solutions, which include tax determination and compliance management services, and fees paid for preparing and filing transaction tax returns on behalf of customers. Under the Company’s subscription agreements, customers select a price plan that includes an allotted maximum number of transactions over the subscription term. Unused transactions are not carried over to the customer’s next subscription term, and customers are not entitled to refunds of fees paid or relief from fees due in the event they do not use the allotted number of transactions. If customers exceed the maximum transaction level within their price plan, the Company will generally upgrade the customer to a higher transaction price plan or, in some cases, charge overage fees on a per transaction basis. The Company’s subscription arrangements do not provide the customer with the right to take possession of the software supporting the cloud-based application services. The Company’s standard subscription contracts are non-cancelable except where contract terms provide rights to cancel in the first 60 days of the contract term. Cancellations under the Company’s standard subscription contracts are not material, and do not have a significant impact on revenue recognized. Tax returns processing services include collection of tax data and amounts, preparation of compliance forms, and submission to taxing authorities. Returns processing services are primarily charged on a subscription basis for an allotted number of returns to process within a given time period. Revenue is recognized ratably over the contractual term of the arrangement, beginning on the date that the service is made available to the customer. The Company invoices its subscription customers for the initial term at contract signing and at each subscription renewal. Initial terms generally range from 12 to 18 months, and renewal periods are typically one year. Amounts that are contractually billable and have been invoiced, or which have been collected as cash, are initially recorded as deferred revenue or contract liabilities. While most of the Company’s customers are invoiced once at the beginning of the term, a portion of customers are invoiced semi-annually, quarterly, or monthly. Included in the total subscription fee for cloud-based solutions are non-refundable upfront fees that are typically charged to the Company’s new customers. These fees are associated with work performed to set up a customer with the Company’s services, and do not represent a distinct good or service. Instead, the fees are included within the transaction price and allocated to the remaining performance obligations in the contract. The Company recognizes revenue for these fees in accordance with the revenue recognition for those performance obligations. Also included in subscription and returns revenue is interest income on funds held for customers. The Company uses trust accounts at FDIC-insured institutions to provide tax remittance services to customers and collect funds from customers in advance of remittance to tax authorities. After collection and prior to remittance, the Company earns interest on these funds. Professional Services Revenue The Company bills for service arrangements on a fixed fee, milestone, or time and materials basis. Professional services revenue includes fees from providing tax analysis, configurations, data migrations, integration, training, and other support services. The transaction price allocated to professional services performance obligations is recognized as revenue as services are performed or upon completion of work. Judgments and Estimates The Company’s contracts with customers often include obligations to provide multiple services to a customer. Determining whether services are considered distinct performance obligations that should be accounted for separately from one another requires judgment. Subscription services and professional services are both distinct performance obligations that are accounted for separately. Judgment is required to determine the standalone selling price (“SSP”) for each distinct performance obligation. The Company allocates revenue to each performance obligation based on the relative SSP. The Company determines SSP for performance obligations based on overall pricing objectives, which take into consideration observable prices, market conditions and entity-specific factors. This includes a review of historical data related to the services being sold and customer demographics. The Company uses a range of amounts to estimate SSP for performance obligations. There is typically more than one SSP for individual services due to the stratification of those services by information such as size and type of customer. The revenue recognition accounting policy for ASC 605 is included in the Annual Report on Form 10-K for the year ended December 31, 2018, which was filed with the SEC on February 28, 2019. The revenue recognition accounting policy for ASC 605 is applied to the disclosures in Note 6, which include amounts presented for 2019. There were no changes to the ASC 605 policy during the first quarter of 2019. Assets Recognized from the Costs to Obtain a Contract with a Customer The Company recognizes an asset for the incremental costs of obtaining a contract with a customer if it expects the benefit of those costs to be longer than one year. The Company has determined that certain costs related to employee sales incentive programs and partner commission programs represent incremental costs of obtaining a contract and therefore should be capitalized. Capitalized costs are included in deferred commissions on the consolidated balance sheets. These deferred commissions are amortized over an estimated period of benefit of generally six years. The Company determined the period of benefit by taking into consideration its past experience with customers, the expected life of acquired technology that generates revenue, industry peers, and other available information. The period of benefit is generally longer than the term of the initial contract because of anticipated renewals. The Company elected to apply the practical expedient to recognize the incremental costs of obtaining a contract as an expense if the amortization period of the asset would have been one year or less.
Recently Adopted Accounting Standard	Recently Adopted Accounting Standards As an “emerging growth company,” the Jumpstart Our Business Startups Act, or the JOBS Act, allows the Company to delay adoption of new or revised accounting pronouncements applicable to public companies until such pronouncements are made applicable to private companies. The Company has elected to use the adoption dates applicable to private companies. As a result, the Company’s consolidated financial statements may not be comparable to the financial statements of issuers who are required to comply with the effective date for new or revised accounting standards that are applicable to public companies. ASU No. 2014-09 In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09 which, along with subsequent ASUs, amends the existing accounting standards for revenue recognition, and is codified as ASC 606. This guidance is based on principles that govern the recognition of revenue at the amount an entity expects to be entitled to receive as services are provided to customers. The Company adopted the new revenue recognition standard in the first quarter of 2019 on a modified retrospective basis and applied the new revenue recognition standard only to contracts that were not completed contracts prior to January 1, 2019. The cumulative effect of the changes made to the consolidated January 1, 2019 balance sheet resulting from the adoption of ASC 606 was as follows (in thousands): Balance at December 31, 2018 Adjustments due to ASC 606 Balance at January 1, 2019 Assets Trade accounts receivable $ 40,287 $ (805 ) $ 39,482 Deferred commissions, current portion — 4,464 4,464 Deferred commissions, net of current portion — 14,803 14,803 Liabilities and shareholders' equity Accrued expenses 42,217 2,090 44,307 Deferred revenue, current portion 125,260 (3,157 ) 122,103 Deferred revenue, net of current portion 9,393 (8,093 ) 1,300 Accumulated deficit (487,602 ) 27,622 (459,980 ) The adoption changed the revenue recognition for non-refundable upfront fees included with new or upgraded subscriptions. Prior to the adoption of the new revenue recognition standard, the Company recognized revenue for these fees over the expected term of the customer relationship. Under the new guidance, the transaction price is allocated to distinct performance obligations. Because upfront fees do not represent a distinct performance obligation, any such fees will be recognized over the period in which distinct performance obligations in the contract are satisfied, which is typically the subscription term. The new revenue recognition standard also changed the determination of the contract term associated with subscriptions that were upgraded during the subscription term. Prior to the adoption of the new revenue recognition standard, additional fees associated with an upgraded subscription for services already delivered were recognized retrospectively upon upgrade. Under the new guidance, the fees related to the upgraded subscriptions are recognized prospectively over the contract term. The adoption also changed the revenue recognition for contracts that include non-standard, extended customer cancellation provisions. Under the new guidance, a contract only exists for the period of time in which a contract cannot be cancelled, which generally corresponds to the termination notice period. Prior to the adoption of the new revenue recognition standard, non-standard, extended cancellation provisions were not a factor in determining the term of a contract. To the extent cash is received for a contract that includes a non-standard, extended cancellation provision, deferred revenue is recognized only for the amount for which the Company has an enforceable right. A contract liability is established for the remaining amount. The new revenue recognition standard requires the Company to estimate variable consideration at contract inception as an increase or decrease to the transaction price. The total transaction price, inclusive of variable consideration, is allocated to performance obligations, or distinct service periods within a performance obligation, on a relative SSP basis and recognized as performance obligations are satisfied. Prior to the adoption of the new revenue recognition standard, overage fees, concessions, and cancellations allowed in the first 60 days of a standard subscription contract were recognized as they occurred. The new revenue recognition standard requires capitalization of certain incremental costs of obtaining a contract, such as certain employee sales commissions and partner commissions, which impacts the period in which the expense is recorded. Prior to the adoption of the new revenue recognition standard, those commission costs were expensed as incurred. Under the new revenue recognition standard, the Company is required to capitalize incremental costs of obtaining a contract and amortize them over the expected period of benefit, which is generally six years. This results in a deferral of sales commission and partner commission expense each period. For further discussion regarding the impacts of adopting the new revenue recognition standard, see Note 6. ASU No. 2016-15 In August 2016, the FASB issued ASU No. 2016-15, related to classification of certain cash receipts and payments. ASU No. 2016-15 is intended to add or clarify guidance on the classification of certain cash receipts and payments in the statement of cash flows and to eliminate the diversity in practice related to such classifications. The guidance in ASU No. 2016-15 is required for annual reporting periods beginning after December 15, 2018 for business entities that are not public, with early adoption permitted. The Company adopted the guidance on January 1, 2019. The adoption had no impact on the consolidated financial statements. ASU No. 2018-07 In June 2018, the FASB issued ASU No. 2018-07, related to stock compensation for nonemployee share-based awards. ASU No. 2018-07 expands the scope of Topic 718 – Compensation – Stock Compensation to include share-based payments issued to nonemployees, with certain exceptions, in order to align the accounting for employees and nonemployees. The guidance in ASU No. 2018-07 is required for annual reporting periods beginning after December 15, 2019 for business entities that are not public, with early adoption permitted. The Company adopted the guidance on January 1, 2019. The adoption had an immaterial impact on the consolidated financial statements.
New Accounting Standards Not Yet Adopted	New Accounting Standards Not Yet Adopted ASU No. 2016-02 In February 2016, the FASB issued ASU No. 2016-02 which requires lessees to generally recognize most operating leases on the balance sheets but record expenses on the income statements in a manner similar to current accounting standards. The guidance is effective in 2020 for business entities that are not public with early adoption permitted. The Company is currently evaluating the impact this guidance will have on the Company’s consolidated financial statements. The Company currently expects that most operating lease commitments will be subject to the new standard and will be recognized as operating lease liabilities and right-of-use assets upon adoption. While the Company has not yet quantified the impact, these adjustments will increase total assets and total liabilities relative to such amounts reported prior to adoption. ASU No. 2018-15 In August 2018, the FASB issued ASU No. 2018-15, related to implementation costs incurred in a cloud computing arrangement that is a service contract. The guidance in ASU No. 2018-15 is required for annual reporting periods beginning after December 15, 2020, for business entities that are not public, with early adoption permitted. The Company is currently evaluating the impact this guidance will have on the Company’s consolidated financial statements.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of the Cumulative Effect of Adoption of ASC 606 within the Consolidated Balance Sheets	The cumulative effect of the changes made to the consolidated January 1, 2019 balance sheet resulting from the adoption of ASC 606 was as follows (in thousands): Balance at December 31, 2018 Adjustments due to ASC 606 Balance at January 1, 2019 Assets Trade accounts receivable $ 40,287 $ (805 ) $ 39,482 Deferred commissions, current portion — 4,464 4,464 Deferred commissions, net of current portion — 14,803 14,803 Liabilities and shareholders' equity Accrued expenses 42,217 2,090 44,307 Deferred revenue, current portion 125,260 (3,157 ) 122,103 Deferred revenue, net of current portion 9,393 (8,093 ) 1,300 Accumulated deficit (487,602 ) 27,622 (459,980 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following financial assets and liabilities are measured at fair value on a recurring basis. The fair values recognized in the accompanying consolidated balance sheets and the level within the fair value hierarchy in which the fair value measurements fall is as follows (in thousands): Fair Value Measurements Using Quoted Prices Significant in Active Other Significant Markets for Observable Unobservable Fair Identical Assets Inputs Inputs March 31, 2019 Value (Level 1) (Level 2) (Level 3) Money market funds $ 140,316 $ 140,316 $ $ Earnout related to acquisitions 5,952 5,952 Fair Value Measurements Using Quoted Prices Significant in Active Other Significant Markets for Observable Unobservable Fair Identical Assets Inputs Inputs December 31, 2018 Value (Level 1) (Level 2) (Level 3) Money market funds $ 138,483 $ 138,483 $ $ Earnout related to acquisitions — —
Summary of Reconciliation of Beginning and Ending Balances of Recurring Fair Value Measurements	A reconciliation of the beginning and ending balances of recurring fair value measurements recognized in the accompanying consolidated balance sheets using significant unobservable (Level 3) inputs, is as follows (in thousands): March 31, December 31, 2019 2018 Earnout liability: Balance beginning of period $ — $ 380 Fair value of earnout liability originally recorded 5,952 — Total unrealized (gains) losses included in other income — (380 ) Balance end of period $ 5,952 $ —

Balance Sheet Detail (Tables)

Balance Sheet Detail (Tables)	3 Months Ended
	Mar. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): Useful March 31, December 31, Life (Years) 2019 2018 Computer equipment and software 3 $ 13,948 $ 12,904 Internally developed software 6 4,075 3,620 Furniture and fixtures 5 6,462 5,850 Office equipment 5 586 586 Leasehold improvements 1 to 10 27,108 26,788 52,179 49,748 Accumulated depreciation (18,360 ) (16,375 ) Property and equipment—net $ 33,819 $ 33,373
Schedule of Prepaid Expense And Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): March 31, December 31, 2019 2018 Prepaid expenses $ 11,080 $ 9,578 Deferred financing costs 853 643 Deposits 115 325 Other 1,207 761 Total $ 13,255 $ 11,307
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): March 31, December 31, 2019 2018 Accrued payroll and related taxes $ 5,359 $ 3,800 Accrued state, federal, and local taxes 1,902 1,827 Accrued bonus 3,252 10,766 Employee stock purchase plan contributions 1,990 6,473 Accrued sales commissions 3,504 6,889 Accrued partner commissions 6,105 5,535 Accrued earnout liabilities 5,980 116 Contract liabilities 4,208 — Accrued purchase price related to acquisitions 1,584 — Other 7,716 6,811 Total $ 41,600 $ 42,217

Acquisitions of Businesses (Tab

Acquisitions of Businesses (Tables)	3 Months Ended
	Mar. 31, 2019
Compli, Inc.
Business Acquisition [Line Items]
Schedule of Estimated Fair Value of Assets Acquired and Liabilities Assumed	Estimated fair values of the assets acquired and the liabilities assumed in the Compli Purchase as of the acquisition date are provided in the following table (in thousands): Assets acquired: Current assets $ 505 Developed technology, customer relationships, and other intangibles 4,288 Goodwill 12,807 Total assets acquired 17,600 Liabilities assumed: Current liabilities 482 Total liabilities assumed 482 Net assets acquired $ 17,118
Summary of Valuation Methodologies, Significant Assumptions and Estimated Useful Lives	The Company utilizes different valuation approaches and methodologies to determine the fair value of acquired intangible assets. A summary of the valuation methodologies, significant assumptions, and estimated useful lives of acquired intangible assets in the Compli Purchase are provided in the below table (in thousands): Intangible Assigned Value Valuation Methodology Discount Rate Estimated Useful Life Customer relationships $ 3,250 Multi-period excess earnings-income approach 13 % 6 years Trademarks and trade names 32 Relief from royalty- income approach 13 % 2 years Developed technology and customer database 910 Relief from royalty- income approach 13 % 6 years Noncompetition agreements 96 With-and-without valuation- income approach 13 % 3 years
Indix Corporation
Business Acquisition [Line Items]
Schedule of Estimated Fair Value of Assets Acquired and Liabilities Assumed	Estimated fair values of the assets acquired and the liabilities assumed in the Indix Purchase as of the acquisition date are provided in the following table (in thousands): Assets acquired: Current assets $ 94 Developed technology 4,472 Goodwill 4,953 Total assets acquired 9,519 Liabilities assumed: Current liabilities 392 Total liabilities assumed 392 Net assets acquired $ 9,127
Summary of Valuation Methodologies, Significant Assumptions and Estimated Useful Lives	The Company utilizes different valuation approaches and methodologies to determine the fair value of acquired intangible assets. A summary of the valuation methodologies, significant assumptions, and estimated useful lives of acquired intangible assets in the Indix Purchase are provided in the below table (in thousands): Intangible Assigned Value Valuation Methodology Discount Rate Estimated Useful Life Developed technology $ 4,472 Relief from royalty- income approach 24.5% 6 years

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue From Contract With Customer [Abstract]
Summary of Impact From Adoption of New Revenue Recognition on Statements	Consolidated Balance Sheets – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated balance sheet as of March 31, 2019 (in thousands): March 31, December 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) (unaudited) (unaudited) (unaudited) Assets Current assets: Cash and cash equivalents $ 146,878 $ — $ 146,878 $ 142,322 Trade accounts receivable—net of allowance for doubtful accounts 45,381 919 46,300 40,287 Deferred commissions 6,062 (6,062 ) — — Prepaid expenses and other current assets 13,255 — 13,255 11,307 Total current assets before customer fund assets 211,576 (5,143 ) 206,433 193,916 Funds held from customers 19,365 — 19,365 13,113 Receivable from customers—net of allowance for doubtful accounts 1,238 — 1,238 270 Total current assets 232,179 (5,143 ) 227,036 207,299 Noncurrent assets: Property and equipment—net 33,819 — 33,819 33,373 Goodwill 78,842 — 78,842 61,300 Intangible assets—net 26,440 — 26,440 19,371 Deferred commissions 19,582 (19,582 ) — — Other noncurrent assets 1,824 — 1,824 1,589 Total assets $ 392,686 $ (24,725 ) $ 367,961 $ 322,932 Liabilities and shareholders' equity Current liabilities: Trade payables $ 9,536 $ — $ 9,536 $ 4,847 Accrued expenses 41,600 (4,208 ) 37,392 42,217 Deferred revenue 131,733 4,951 136,684 125,260 Total current liabilities before customer fund obligations 182,869 743 183,612 172,324 Customer fund obligations 20,502 — 20,502 13,349 Total current liabilities 203,371 743 204,114 185,673 Noncurrent liabilities: Deferred revenue 981 8,499 9,480 9,393 Deferred tax liability 599 — 599 560 Deferred rent 16,927 — 16,927 17,317 Other noncurrent liabilities 1,835 — 1,835 436 Total liabilities 223,713 9,242 232,955 213,379 Commitments and contingencies Shareholders' equity: Preferred stock — — — — Common stock 7 — 7 7 Additional paid-in capital 640,996 — 640,996 599,493 Accumulated other comprehensive income (loss) (2,807 ) — (2,807 ) (2,345 ) Accumulated deficit (469,223 ) (33,967 ) (503,190 ) (487,602 ) Total shareholders’ equity 168,973 (33,967 ) 135,006 109,553 Total liabilities and shareholders' equity $ 392,686 $ (24,725 ) $ 367,961 $ 322,932 Consolidated Statements of Operations (Unaudited) – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated statement of operations for the three months ended March 31, 2019 (in thousands, except per share amounts): For the Three Months Ended March 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) Revenue: Subscription and returns $ 78,231 $ 84 $ 78,315 $ 57,870 Professional services 6,739 (53 ) 6,686 3,507 Total revenue 84,970 31 85,001 61,377 Cost of revenue: Subscription and returns 20,978 — 20,978 14,817 Professional services 4,329 — 4,329 2,692 Total cost of revenue 25,307 — 25,307 17,509 Gross profit 59,663 31 59,694 43,868 Operating expenses: Research and development 15,956 — 15,956 12,619 Sales and marketing 38,208 6,376 44,584 37,307 General and administrative 15,234 — 15,234 9,211 Total operating expenses 69,398 6,376 75,774 59,137 Operating loss (9,735 ) (6,345 ) (16,080 ) (15,269 ) Other (income) expense: Interest income (767 ) — (767 ) (36 ) Interest expense 111 — 111 894 Other (income) expense, net 48 — 48 (30 ) Total other (income) expense, net (608 ) — (608 ) 828 Loss before income taxes (9,127 ) (6,345 ) (15,472 ) (16,097 ) Provision for (benefit from) income taxes 116 — 116 (848 ) Net loss $ (9,243 ) $ (6,345 ) $ (15,588 ) $ (15,249 ) Net loss per share attributable to common shareholders, basic and diluted $ (0.14 ) $ (0.09 ) $ (0.23 ) $ (2.47 ) Weighted average shares of common stock outstanding, basic and diluted 68,381 — 68,381 6,170 Consolidated Statements of Comprehensive Loss (Unaudited) – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated statement of comprehensive loss for the three months ended March 31, 2019 (in thousands): For the Three Months Ended March 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) Net loss $ (9,243 ) $ (6,345 ) $ (15,588 ) $ (15,249 ) Other comprehensive income (loss)—Foreign currency translation (462 ) — (462 ) 603 Total comprehensive loss $ (9,705 ) $ (6,345 ) $ (16,050 ) $ (14,646 ) Consolidated Statements of Cash Flows (Unaudited) – Reconciliation of the Impacts from the Adoption of the New Revenue Recognition Standard The following schedule summarizes the impacts from the adoption of the new revenue recognition standard on the consolidated statement of cash flows for the three months ended March 31, 2019 (in thousands): For the Three Months Ended March 31, 2019 2018 As Reported (ASC 606) Impacts from Adoption Without Adoption (ASC 605) As Reported (ASC 605) Cash flows from operating activities: Net loss $ (9,243 ) $ (6,345 ) $ (15,588 ) $ (15,249 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 3,681 — 3,681 2,990 Stock-based compensation 6,560 — 6,560 3,510 Deferred tax expense 39 — 39 (1,018 ) Amortization of deferred rent (133 ) — (133 ) 301 Non-cash change in earnout liability — — — (71 ) Non-cash bad debt expense 222 — 222 67 Other 58 — 58 180 Changes in operating assets and liabilities: Trade accounts receivable (5,535 ) (114 ) (5,649 ) (6,428 ) Prepaid expenses and other current assets (1,705 ) — (1,705 ) (1,907 ) Other long-term assets (236 ) — (236 ) 110 Trade payables 3,590 — 3,590 (1,736 ) Accrued expenses and other current liabilities (10,373 ) (2,118 ) (12,491 ) (5,771 ) Deferred commissions (6,377 ) 6,377 — — Deferred revenue 9,031 2,200 11,231 11,647 Net cash used in operating activities (10,421 ) — (10,421 ) (13,375 ) Cash flows from investing activities: Net increase in customer fund assets (7,224 ) — (7,224 ) (18,527 ) Cash paid for acquired intangible assets (131 ) — (131 ) — Cash paid for acquisitions of businesses (17,310 ) — (17,310 ) — Purchase of property and equipment (2,114 ) — (2,114 ) (3,625 ) Net cash used in investing activities (26,779 ) — (26,779 ) (22,152 ) Cash flows from financing activities: Proceeds from credit facility — — — 18,000 Payments of deferred financing costs (39 ) — (39 ) — Net increase in customer fund obligations 7,143 — 7,143 18,527 Proceeds from exercise of stock options and common stock warrants 27,311 — 27,311 326 Proceeds from purchases of stock under employee stock purchase plan 7,664 — 7,664 — Taxes paid related to net share settlement of stock-based awards (93 ) — (93 ) (2,016 ) Repurchase of shares — — — (819 ) Net cash provided by financing activities 41,986 — 41,986 34,018 Foreign currency effect on cash and cash equivalents (230 ) (230 ) 56 Net change in cash and cash equivalents 4,556 — 4,556 (1,453 ) Cash and cash equivalents—Beginning of period 142,322 — 142,322 14,075 Cash and cash equivalents—End of period $ 146,878 $ — $ 146,878 $ 12,622
Summary of Total Revenues	The following table disaggregates revenue generated within the United States (U.S.) from revenue generated from customers outside of the U.S. Revenue for transaction tax compliance in the U.S. is further disaggregated based on the solutions or services purchased by customers. Total revenues consisted of the following (in thousands): For the Three Months Ended March 31, 2019 2018 Revenue (U.S.): Subscription and returns Tax determination $ 45,232 $ 33,150 Tax returns and compliance management 26,686 21,800 Interest income on funds held for customers 729 — Total subscription and returns 72,647 54,950 Professional services 5,735 2,967 Total revenue (U.S.) 78,382 57,917 Total revenue (non-U.S.) 6,588 3,460 Total revenue $ 84,970 $ 61,377
Summary of Activity Impacting Contract Liabilities	A summary of the activity impacting the contract liabilities during the three months ended March 31, 2019 is presented below (in thousands): Contract Liabilities Balance at December 31, 2018 $ — Adoption of ASC 606 2,090 Contract liabilities transferred to deferred revenue (1,257 ) Addition to contract liabilities 3,375 Balance at March 31, 2019 $ 4,208
Summary of Activity Impacting Deferred Revenue	Deferred Revenue A summary of the activity impacting deferred revenue balances during the three months ended March 31, 2019 is presented below (in thousands): Deferred Revenue Balance at December 31, 2018 $ 134,653 Adoption of ASC 606 (11,250 ) Revenue recognized (84,970 ) Additional amounts deferred 94,281 Balance at March 31, 2019 $ 132,714
Summary of Activity Impacting Deferred Commissions	A summary of the activity impacting the deferred commissions during the three months ended March 31, 2019 is presented below (in thousands): Deferred Commissions Balance at December 31, 2018 $ — Adoption of ASC 606 19,267 Additional commissions deferred 7,656 Amortization of deferred commissions (1,279 ) Balance at March 31, 2019 $ 25,644

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Finite-lived Intangible Assets	Finite-lived intangible assets consisted of the following (in thousands): March 31, 2019 Average Useful Life (Years) Gross Accumulated Amortization Net Customer relationships 3 to 10 $ 18,652 $ (9,694 ) $ 8,958 Developed technology 3 to 8 36,314 (18,976 ) 17,338 Noncompete agreements 3 to 5 669 (554 ) 115 Tradename and trademarks 1 to 4 452 (423 ) 29 $ 56,087 $ (29,647 ) $ 26,440 December 31, 2018 Average Useful Life (Years) Gross Accumulated Amortization Net Customer relationships 3 to 10 $ 15,412 $ (9,202 ) $ 6,210 Developed technology 3 to 8 30,935 (17,806 ) 13,129 Noncompete agreements 3 to 5 574 (542 ) 32 Tradename and trademarks 1 to 4 420 (420 ) — $ 47,341 $ (27,970 ) $ 19,371
Schedule of Changes in Carrying Amount of Goodwill	Changes in the carrying amount of goodwill through March 31, 2019 are summarized as follows (in thousands): Balance—December 31, 2018 $ 61,300 Acquisition of Compli 12,807 Acquisition of Indix 4,953 Cumulative translation adjustments (218 ) Balance—March 31, 2019 $ 78,842

Convertible Preferred Stock a_2

Convertible Preferred Stock and Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Stockholders Equity Note [Abstract]
Summary of Changes of Convertible Preferred Stock and Shareholders' Equity (Deficit)	The changes to the Company’s shareholders’ equity for the three months ended March 31, 2019 is as follows (in thousands, except per share data): Accumulated Additional Other Total Common Stock Paid-In Comprehensive Accumulated Shareholders’ Shares Amount Capital Income (Loss) Deficit Equity Balance at January 1, 2019 66,768,563 $ 7 $ 599,493 $ (2,345 ) $ (487,602 ) $ 109,553 Impact of adoption of new accounting pronouncements (see Note 2) 27,622 27,622 Exercise of stock options 2,763,291 27,311 27,311 Shares tendered for cashless redemption of stock options (2,805 ) (93 ) (93 ) Stock-based compensation cost 6,571 6,571 Shares issued under employee stock purchase plan 372,764 7,664 7,664 Shares issued to purchase intangible assets 1,634 50 50 Loss on translation adjustment (462 ) (462 ) Net loss (9,243 ) (9,243 ) Balance at March 31, 2019 69,903,447 $ 7 $ 640,996 $ (2,807 ) $ (469,223 ) $ 168,973 The changes to the Company’s convertible preferred stock and shareholders’ equity (deficit) for the three months ended March 31, 2018 is as follows (in thousands, except per share data): Accumulated Convertible Additional Other Total Preferred Stock Common Stock Paid-In Comprehensive Accumulated Shareholders’ Shares Amount Shares Amount Capital Income (Loss) Deficit Deficit Balance at January 1, 2018 101,786,205 $ 370,921 5,992,293 $ 1 $ 18,121 $ 338 $ (412,052 ) $ (393,592 ) Exercise of stock options 785,991 6,025 6,025 Shares tendered for cashless redemption of stock options (465,710 ) (7,715 ) (7,715 ) Stock-based compensation cost 3,517 3,517 Repurchase of shares (10,000 ) (67 ) (48,152 ) (752 ) (752 ) Gain on translation adjustment 603 603 Net loss (15,249 ) (15,249 ) Balance at March 31, 2018 101,776,205 $ 370,854 6,264,422 $ 1 $ 19,196 $ 941 $ (427,301 ) $ (407,163 )

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 2019
Summary of Stock-Based Compensation Expense Related to Equity Incentive Rewards	The Company recognized total stock-based compensation cost related to equity incentive awards as follows (in thousands): For the Three Months Ended March 31, 2019 2018 Stock-based compensation cost: Common stock warrants $ — $ 512 Stock options 3,917 3,005 Restricted stock units 1,698 — Employee stock purchase plan 956 — Total stock-based compensation cost $ 6,571 $ 3,517
Summary of Stock Option Activity	Stock Options The following table summarizes stock option activity for the Company’s stock-based compensation plans for the three months ended March 31, 2019: Weighted Weighted Average Aggregate Average Remaining Intrinsic Exercise Contractual Value Shares Price Life (Years) (in thousands) Options outstanding as of December 31, 2018 11,094,070 $ 12.17 6.81 $ 210,523 Options granted 801,002 41.41 Options exercised (2,763,291 ) 9.89 Options cancelled or expired (101,202 ) 14.96 Options outstanding as of March 31, 2019 9,030,579 15.44 7.10 364,420 Options exercisable as of March 31, 2019 4,744,344 $ 9.54 5.66 $ 219,420
Summary of Options Outstanding and Vested by Range of Exercise Prices	A summary of options outstanding and vested as of March 31, 2019 is as follows: Options Outstanding Options Vested and Exercisable Exercise Number Weighted Average Number Vested Weighted Average Prices Outstanding Life (in Years) and Exercisable Life (in Years) $0.96 to $1.90 706,971 1.95 706,971 1.95 2.86 to 6.40 859,450 4.02 859,450 4.02 8.04 to 11.72 702,499 4.95 702,499 4.95 12.20 to 15.06 3,444,812 7.39 2,000,706 7.18 16.06 to 24.00 2,325,345 8.87 471,594 8.80 31.99 to 55.79 991,502 9.76 3,124 9.78 9,030,579 4,744,344
Summary of Fair Value Estimated Using Black-Scholes Option Pricing Model Assumptions	For the options granted during the periods presented, the fair value of options was estimated using the Black-Scholes option-pricing model with the following assumptions: For the Three Months Ended March 31, 2019 2018 Fair market value of common stock $39.76 - 55.79 $16.86 Volatility 40% 40% Expected term 6 years 6 years Expected dividend yield n/a n/a Risk-free interest rate 2.31% - 2.65% 2.55%
Summary of RSU Activity	The following table summarizes RSU activity for the Company’s stock-based compensation plans for the three months ended March 31, 2019: Weighted Average Grant Date Fair Restricted Stock Units Value Per Share RSUs outstanding as of December 31, 2018 74,424 $ 32.69 RSUs granted 955,753 42.68 RSUs vested — RSUs cancelled (11,852 ) 39.76 RSUs outstanding as of March 31, 2019 1,018,325 $ 41.98
2018 Employee Stock Purchase Plan
Summary of Fair Value Estimated Using Black-Scholes Option Pricing Model Assumptions	For the Three Months Ended March 31, 2019 Fair market value of common stock $40.60 Volatility 40% Expected term 0.5 years Expected dividend yield n/a Risk-free interest rate 2.59%

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Shareholders (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Common Share	The following table sets forth the computation of basic and diluted net loss per common share (in thousands, except per share amounts): For the Three Months Ended March 31, 2019 2018 Numerator: Net loss attributable to common shareholders $ (9,243 ) $ (15,249 ) Denominator: Weighted-average common shares outstanding-basic 68,381 6,170 Dilutive effect of share equivalents resulting from stock options, restricted stock units, common stock warrants, and convertible preferred shares (as converted) — — Weighted-average common shares outstanding-diluted 68,381 6,170 Net loss per common share, basic and diluted $ (0.14 ) $ (2.47 )
Schedule of Potential Shares Not Included in the Computation of Diluted Earnings Per Share	The following weighted-average outstanding shares of common stock equivalents were excluded from the computation of diluted net loss per share attributable to common shareholders for the periods presented because the impact of including them would have been antidilutive (in thousands): For the Three Months Ended March 31, 2019 2018 Options to purchase common shares 10,237 11,286 Unvested restricted stock units 631 — Employee stock purchase plan shares 14 — Common stock warrants — 549 Convertible preferred shares (as converted) — 50,889 Total 10,882 62,724

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2019USD ($)Segment
Accounting Policies [Line Items]
Number of operating segment | Segment	1
Impairment of long-lived assets | $	$ 0
Tax position likely of being realized upon ultimate settlement	greater than 50%
Percentage of likelihood of realization of tax position upon ultimate settlement, minimum	50.00%
Contract payment net terms	30 days
Revenue recognition, contractual renewal period	1 year
Deferred commission amortized period	6 years
Concessions and cancellations period allowed for standard subscription contract prior to adoption	60 days
Minimum
Accounting Policies [Line Items]
Revenue recognition initial contractual term	12 months
Maximum
Accounting Policies [Line Items]
Revenue recognition initial contractual term	18 months
Amortization period of asset	1 year

Significant Accounting Polici_5

Significant Accounting Policies - Summary of the Cumulative Effect of Adoption of ASC 606 within the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Trade accounts receivable—net of allowance for doubtful accounts of $539 and $521, respectively	$ 45,381	$ 39,482	$ 40,287
Deferred commissions, current portion	6,062	4,464	0
Deferred commissions, net of current portion	19,582	14,803	0
Liabilities and shareholders' equity
Accrued expenses	41,600	44,307	42,217
Deferred revenue, current portion	131,733	122,103	125,260
Deferred revenue, net of current portion	981	1,300	9,393
Accumulated deficit	(469,223)	(459,980)	$ (487,602)
ASC 606 | Difference between Revenue Guidance in Effect before and after Topic 606
Assets
Trade accounts receivable—net of allowance for doubtful accounts of $539 and $521, respectively	919	(805)
Deferred commissions, current portion	(6,062)	4,464
Deferred commissions, net of current portion	(19,582)	14,803
Liabilities and shareholders' equity
Accrued expenses	(4,208)	2,090
Deferred revenue, current portion	4,951	(3,157)
Deferred revenue, net of current portion	8,499	(8,093)
Accumulated deficit	$ (33,967)	$ 27,622

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Earnout Related to Acquisitions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Liabilities	$ 5,952	$ 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Earnout Related to Acquisitions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Liabilities		0
Significant Other Observable Inputs (Level 2) | Earnout Related to Acquisitions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Liabilities		0
Significant Unobservable Inputs (Level 3) | Earnout Related to Acquisitions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Liabilities	5,952	0
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets	140,316	138,483
Money Market Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets	$ 140,316	$ 138,483

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Feb. 06, 2019	Jan. 22, 2019	Dec. 31, 2018	Mar. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability	$ 5,952				$ 0
Fair Value, Measurements, Non-Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurements on a non-recurring basis	$ 0
Compli, Inc.
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability			$ 3,800
Indix Corporation
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability		$ 2,200
Minimum | Gyori
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability				$ 0
Discount Rate | Maximum | Discounted Cash Flow and Monte Carlo Simulations | Indix Corporation
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate utilized for valuation of earnout liability	5.80%
Discount Rate | Minimum | Discounted Cash Flow and Monte Carlo Simulations | Compli, Inc.
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate utilized for valuation of earnout liability	5.40%
Discount Rate | Minimum | Discounted Cash Flow and Monte Carlo Simulations | Indix Corporation
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate utilized for valuation of earnout liability	5.40%

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Reconciliation of Beginning and Ending Balances of Recurring Fair Value Measurements (Details) - Recurring Basis - Significant Unobservable Inputs (Level 3) - Earnout Related to Acquisitions - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Earnout liability:
Balance beginning of period	$ 0	$ 380
Fair value of earnout liability originally recorded	5,952	0
Total unrealized (gains) losses included in other income	0	(380)
Balance end of period	$ 5,952	$ 0

Balance Sheet Detail - Property

Balance Sheet Detail - Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 52,179	$ 49,748
Accumulated depreciation	(18,360)	(16,375)
Property and equipment—net	33,819	33,373
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 13,948	12,904
Property and equipment, Useful Life	3 years
Internally Developed Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,075	3,620
Property and equipment, Useful Life	6 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,462	5,850
Property and equipment, Useful Life	5 years
Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 586	586
Property and equipment, Useful Life	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 27,108	$ 26,788
Leasehold Improvements | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	1 year
Leasehold Improvements | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	10 years

Balance Sheet Detail - Addition

Balance Sheet Detail - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Depreciation expense	$ 2	$ 1.6

Balance Sheet Detail - Prepaid

Balance Sheet Detail - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Prepaid Expense And Other Assets Current [Abstract]
Prepaid expenses	$ 11,080	$ 9,578
Deferred financing costs	853	643
Deposits	115	325
Other	1,207	761
Total	$ 13,255	$ 11,307

Balance Sheet Detail - Accrued

Balance Sheet Detail - Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Accrued Liabilities Current [Abstract]
Accrued payroll and related taxes	$ 5,359		$ 3,800
Accrued state, federal, and local taxes	1,902		1,827
Accrued bonus	3,252		10,766
Employee stock purchase plan contributions	1,990		6,473
Accrued sales commissions	3,504		6,889
Accrued partner commissions	6,105		5,535
Accrued earnout liabilities	5,980		116
Contract liabilities	4,208		0
Accrued purchase price related to acquisitions	1,584		0
Other	7,716		6,811
Total	$ 41,600	$ 44,307	$ 42,217

Acquisitions of Businesses - Ad

Acquisitions of Businesses - Additional Information (Details) - USD ($) $ in Thousands	Feb. 06, 2019	Jan. 22, 2019	Mar. 31, 2019	Mar. 31, 2019	Mar. 31, 2018	Jan. 22, 2020	Jan. 31, 2020	Dec. 31, 2018
Business Acquisition [Line Items]
Accrued value of earnout related to acquisition			$ 5,952	$ 5,952	$ 0
Goodwill			78,842	78,842				$ 61,300
Revenues				84,970	61,377
Loss before income taxes				$ (9,127)	$ (16,097)
Compli, Inc.
Business Acquisition [Line Items]
Total consideration transferred		$ 17,100
Consideration in cash		11,800
Accrued value of earnout related to acquisition		3,800
Goodwill		$ 12,807
Revenues			800
Loss before income taxes			(100)
Compli, Inc. | Scenario Forecast
Business Acquisition [Line Items]
Consideration in cash						$ 1,600
Maximum Annual Payout Earned							$ 4,000
Indix Corporation
Business Acquisition [Line Items]
Total consideration transferred	$ 9,100
Consideration in cash	5,500
Accrued value of earnout related to acquisition	2,200
Maximum Annual Payout Earned	3,000
Goodwill	4,953
Loss before income taxes			$ (700)
Additional cash to be paid, as consideration, after eighteen months	1,400
Indix Corporation | Within Three Months from Closing Date of Acquisition
Business Acquisition [Line Items]
Maximum Annual Payout Earned	500
Indix Corporation | Within Seven Months from Closing Date of Acquisition
Business Acquisition [Line Items]
Maximum Annual Payout Earned	650
Indix Corporation | Within 8 Months from Closing Date of Acquisition
Business Acquisition [Line Items]
Maximum Annual Payout Earned	650
Indix Corporation | Within 12 Months from Closing Date of Acquisition
Business Acquisition [Line Items]
Maximum Annual Payout Earned	$ 1,200

Acquisitions of Businesses - Sc

Acquisitions of Businesses - Schedule of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Feb. 06, 2019	Jan. 22, 2019	Dec. 31, 2018
Assets acquired:
Goodwill	$ 78,842			$ 61,300
Compli, Inc.
Assets acquired:
Current assets			$ 505
Developed technology			4,288
Goodwill			12,807
Total assets acquired			17,600
Liabilities assumed:
Current liabilities			482
Total liabilities assumed			482
Net assets acquired			$ 17,118
Indix Corporation
Assets acquired:
Current assets		$ 94
Developed technology		4,472
Goodwill		4,953
Total assets acquired		9,519
Liabilities assumed:
Current liabilities		392
Total liabilities assumed		392
Net assets acquired		$ 9,127

Acquisitions of Businesses - Su

Acquisitions of Businesses - Summary Of The Valuation Methodologies Significant Assumptions, And Estimated Useful Lives Of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Feb. 06, 2019	Jan. 22, 2019
Compli, Inc.
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 4,288
Compli, Inc. | Customer Relationships
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 3,250
Valuation Methodology		Multi-period excess earnings-income approach
Discount Rate		13.00%
Intangible asset, useful life		6 years
Compli, Inc. | Tradename and Trademarks
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 32
Valuation Methodology		Relief from royalty- income approach
Discount Rate		13.00%
Intangible asset, useful life		2 years
Compli, Inc. | Developed Technology
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 910
Valuation Methodology		Relief from royalty- income approach
Discount Rate		13.00%
Intangible asset, useful life		6 years
Compli, Inc. | Noncompete Agreements
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 96
Valuation Methodology		With-and-without valuation- income approach
Discount Rate		13.00%
Intangible asset, useful life		3 years
Indix Corporation
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 4,472
Indix Corporation | Developed Technology
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 4,472
Valuation Methodology	Relief from royalty- income approach
Discount Rate	24.50%
Intangible asset, useful life	6 years

Revenue - Consolidated Balance

Revenue - Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 146,878		$ 142,322	$ 12,622	$ 14,075
Trade accounts receivable—net of allowance for doubtful accounts of $539 and $521, respectively	45,381	$ 39,482	40,287
Deferred commissions	6,062	4,464	0
Prepaid expenses and other current assets	13,255		11,307
Total current assets before customer fund assets	211,576		193,916
Funds held from customers	19,365		13,113
Receivable from customers—net of allowance of $283 and $198, respectively	1,238		270
Total current assets	232,179		207,299
Noncurrent assets:
Property and equipment—net	33,819		33,373
Goodwill	78,842		61,300
Intangible assets—net	26,440		19,371
Deferred commissions	19,582	14,803	0
Other noncurrent assets	1,824		1,589
Total assets	392,686		322,932
Current liabilities:
Trade payables	9,536		4,847
Accrued expenses	41,600	44,307	42,217
Deferred revenue	131,733	122,103	125,260
Total current liabilities before customer fund obligations	182,869		172,324
Customer fund obligations	20,502		13,349
Total current liabilities	203,371		185,673
Noncurrent liabilities:
Deferred revenue	981	1,300	9,393
Deferred tax liability	599		560
Deferred rent	16,927		17,317
Other noncurrent liabilities	1,835		436
Total liabilities	223,713		213,379
Commitments and contingencies	0		0
Shareholders' equity:
Preferred stock, $0.0001 par value– no shares issued and outstanding at March 31, 2019 and December 31, 2018, and 20,000 shares authorized as of March 31, 2019 and December 31, 2018	0		0
Common stock	7		7
Additional paid-in capital	640,996		599,493
Accumulated other comprehensive income (loss)	(2,807)		(2,345)
Accumulated deficit	(469,223)	(459,980)	(487,602)
Total shareholders’ equity	168,973		109,553	$ (407,163)	$ (393,592)
Total liabilities and shareholders' equity	392,686		322,932
ASU 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Current assets:
Cash and cash equivalents	0		0
Trade accounts receivable—net of allowance for doubtful accounts of $539 and $521, respectively	919	(805)
Deferred commissions	(6,062)	4,464
Prepaid expenses and other current assets	0
Total current assets before customer fund assets	(5,143)
Funds held from customers	0
Receivable from customers—net of allowance of $283 and $198, respectively	0
Total current assets	(5,143)
Noncurrent assets:
Property and equipment—net	0
Goodwill	0
Intangible assets—net	0
Deferred commissions	(19,582)	14,803
Other noncurrent assets	0
Total assets	(24,725)
Current liabilities:
Trade payables	0
Accrued expenses	(4,208)	2,090
Deferred revenue	4,951	(3,157)
Total current liabilities before customer fund obligations	743
Customer fund obligations	0
Total current liabilities	743
Noncurrent liabilities:
Deferred revenue	8,499	(8,093)
Deferred tax liability	0
Deferred rent	0
Other noncurrent liabilities	0
Total liabilities	9,242
Commitments and contingencies	0
Shareholders' equity:
Preferred stock, $0.0001 par value– no shares issued and outstanding at March 31, 2019 and December 31, 2018, and 20,000 shares authorized as of March 31, 2019 and December 31, 2018	0
Common stock	0
Additional paid-in capital	0
Accumulated other comprehensive income (loss)	0
Accumulated deficit	(33,967)	$ 27,622
Total shareholders’ equity	(33,967)
Total liabilities and shareholders' equity	(24,725)
ASU 2014-09 | Without Adoption (ASC 605)
Current assets:
Cash and cash equivalents	146,878		$ 142,322
Trade accounts receivable—net of allowance for doubtful accounts of $539 and $521, respectively	46,300
Deferred commissions	0
Prepaid expenses and other current assets	13,255
Total current assets before customer fund assets	206,433
Funds held from customers	19,365
Receivable from customers—net of allowance of $283 and $198, respectively	1,238
Total current assets	227,036
Noncurrent assets:
Property and equipment—net	33,819
Goodwill	78,842
Intangible assets—net	26,440
Deferred commissions	0
Other noncurrent assets	1,824
Total assets	367,961
Current liabilities:
Trade payables	9,536
Accrued expenses	37,392
Deferred revenue	136,684
Total current liabilities before customer fund obligations	183,612
Customer fund obligations	20,502
Total current liabilities	204,114
Noncurrent liabilities:
Deferred revenue	9,480
Deferred tax liability	599
Deferred rent	16,927
Other noncurrent liabilities	1,835
Total liabilities	232,955
Commitments and contingencies	0
Shareholders' equity:
Preferred stock, $0.0001 par value– no shares issued and outstanding at March 31, 2019 and December 31, 2018, and 20,000 shares authorized as of March 31, 2019 and December 31, 2018	0
Common stock	7
Additional paid-in capital	640,996
Accumulated other comprehensive income (loss)	(2,807)
Accumulated deficit	(503,190)
Total shareholders’ equity	135,006
Total liabilities and shareholders' equity	$ 367,961

Revenue - Consolidated Statemen

Revenue - Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue:
Revenues	$ 84,970	$ 61,377
Cost of revenue:
Cost of revenues	25,307	17,509
Gross profit	59,663	43,868
Operating expenses:
Research and development	15,956	12,619
Sales and marketing	38,208	37,307
General and administrative	15,234	9,211
Total operating expenses	69,398	59,137
Operating loss	(9,735)	(15,269)
Other (income) expense:
Interest income	(767)	(36)
Interest expense	111	894
Other (income) expense, net	48	(30)
Total other (income) expense, net	(608)	828
Loss before income taxes	(9,127)	(16,097)
Provision for (benefit from) income taxes	116	(848)
Net loss	$ (9,243)	$ (15,249)
Net loss per share attributable to common shareholders, basic and diluted	$ (0.14)	$ (2.47)
Weighted average shares of common stock outstanding, basic and diluted	68,381	6,170
Subscription and Returns
Revenue:
Revenues	$ 78,231	$ 57,870
Cost of revenue:
Cost of revenues	20,978	14,817
Professional Services
Revenue:
Revenues	6,739	3,507
Cost of revenue:
Cost of revenues	4,329	$ 2,692
ASU 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue:
Revenues	31
Cost of revenue:
Cost of revenues	0
Gross profit	31
Operating expenses:
Research and development	0
Sales and marketing	6,376
General and administrative	0
Total operating expenses	6,376
Operating loss	(6,345)
Other (income) expense:
Interest income	0
Interest expense	0
Other (income) expense, net	0
Total other (income) expense, net	0
Loss before income taxes	(6,345)
Provision for (benefit from) income taxes	0
Net loss	$ (6,345)
Net loss per share attributable to common shareholders, basic and diluted	$ (0.09)
Weighted average shares of common stock outstanding, basic and diluted	0
ASU 2014-09 | Without Adoption (ASC 605)
Revenue:
Revenues	$ 85,001
Cost of revenue:
Cost of revenues	25,307
Gross profit	59,694
Operating expenses:
Research and development	15,956
Sales and marketing	44,584
General and administrative	15,234
Total operating expenses	75,774
Operating loss	(16,080)
Other (income) expense:
Interest income	(767)
Interest expense	111
Other (income) expense, net	48
Total other (income) expense, net	(608)
Loss before income taxes	(15,472)
Provision for (benefit from) income taxes	116
Net loss	$ (15,588)
Net loss per share attributable to common shareholders, basic and diluted	$ (0.23)
Weighted average shares of common stock outstanding, basic and diluted	68,381
ASU 2014-09 | Subscription and Returns | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue:
Revenues	$ 84
Cost of revenue:
Cost of revenues	0
ASU 2014-09 | Subscription and Returns | Without Adoption (ASC 605)
Revenue:
Revenues	78,315
Cost of revenue:
Cost of revenues	20,978
ASU 2014-09 | Professional Services | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue:
Revenues	(53)
Cost of revenue:
Cost of revenues	0
ASU 2014-09 | Professional Services | Without Adoption (ASC 605)
Revenue:
Revenues	6,686
Cost of revenue:
Cost of revenues	$ 4,329

Revenue - Consolidated Statem_2

Revenue - Consolidated Statements of Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	$ (9,243)	$ (15,249)
Other comprehensive income (loss)—Foreign currency translation	(462)	603
Total comprehensive loss	(9,705)	$ (14,646)
ASU 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	(6,345)
Other comprehensive income (loss)—Foreign currency translation	0
Total comprehensive loss	(6,345)
ASU 2014-09 | Without Adoption (ASC 605)
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	(15,588)
Other comprehensive income (loss)—Foreign currency translation	(462)
Total comprehensive loss	$ (16,050)

Revenue - Consolidated Statem_3

Revenue - Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (9,243)	$ (15,249)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,681	2,990
Stock-based compensation	6,560	3,510
Deferred tax expense	39	(1,018)
Amortization of deferred rent	(133)	301
Non-cash change in earnout liability	0	(71)
Non-cash bad debt expense	222	67
Other	58	180
Changes in operating assets and liabilities:
Trade accounts receivable	(5,535)	(6,428)
Prepaid expenses and other current assets	(1,705)	(1,907)
Other long-term assets	(236)	110
Trade payables	3,590	(1,736)
Accrued expenses and other current liabilities	(10,373)	(5,771)
Deferred commissions	(6,377)	0
Deferred revenue	9,031	11,647
Net cash used in operating activities	(10,421)	(13,375)
Cash flows from investing activities:
Net increase in customer fund assets	(7,224)	(18,527)
Cash paid for acquired intangible assets	(131)	0
Cash paid for acquisitions of businesses	(17,310)	0
Purchase of property and equipment	(2,114)	(3,625)
Net cash used in investing activities	(26,779)	(22,152)
Cash flows from financing activities:
Proceeds from credit facility	0	18,000
Payments of deferred financing costs	(39)	0
Net increase in customer fund obligations	7,143	18,527
Proceeds from exercise of stock options and common stock warrants	27,311	326
Proceeds from purchases of stock under employee stock purchase plan	7,664	0
Taxes paid related to net share settlement of stock-based awards	(93)	(2,016)
Repurchase of shares	0	(819)
Net cash provided by financing activities	41,986	34,018
Foreign currency effect on cash and cash equivalents	(230)	56
Net change in cash and cash equivalents	4,556	(1,453)
Cash and cash equivalents—Beginning of period	142,322	14,075
Cash and cash equivalents—End of period	146,878	$ 12,622
ASU 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Cash flows from operating activities:
Net loss	(6,345)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	0
Stock-based compensation	0
Deferred tax expense	0
Amortization of deferred rent	0
Non-cash change in earnout liability	0
Non-cash bad debt expense	0
Other	0
Changes in operating assets and liabilities:
Trade accounts receivable	(114)
Prepaid expenses and other current assets	0
Other long-term assets	0
Trade payables	0
Accrued expenses and other current liabilities	(2,118)
Deferred commissions	6,377
Deferred revenue	2,200
Net cash used in operating activities	0
Cash flows from investing activities:
Net increase in customer fund assets	0
Cash paid for acquired intangible assets	0
Cash paid for acquisitions of businesses	0
Purchase of property and equipment	0
Net cash used in investing activities	0
Cash flows from financing activities:
Proceeds from credit facility	0
Payments of deferred financing costs	0
Net increase in customer fund obligations	0
Proceeds from exercise of stock options and common stock warrants	0
Proceeds from purchases of stock under employee stock purchase plan	0
Taxes paid related to net share settlement of stock-based awards	0
Repurchase of shares	0
Net cash provided by financing activities	0
Foreign currency effect on cash and cash equivalents	0
Net change in cash and cash equivalents	0
Cash and cash equivalents—Beginning of period	0
Cash and cash equivalents—End of period	0
ASU 2014-09 | Without Adoption (ASC 605)
Cash flows from operating activities:
Net loss	(15,588)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,681
Stock-based compensation	6,560
Deferred tax expense	39
Amortization of deferred rent	(133)
Non-cash change in earnout liability	0
Non-cash bad debt expense	222
Other	58
Changes in operating assets and liabilities:
Trade accounts receivable	(5,649)
Prepaid expenses and other current assets	(1,705)
Other long-term assets	(236)
Trade payables	3,590
Accrued expenses and other current liabilities	(12,491)
Deferred commissions	0
Deferred revenue	11,231
Net cash used in operating activities	(10,421)
Cash flows from investing activities:
Net increase in customer fund assets	(7,224)
Cash paid for acquired intangible assets	(131)
Cash paid for acquisitions of businesses	(17,310)
Purchase of property and equipment	(2,114)
Net cash used in investing activities	(26,779)
Cash flows from financing activities:
Proceeds from credit facility	0
Payments of deferred financing costs	(39)
Net increase in customer fund obligations	7,143
Proceeds from exercise of stock options and common stock warrants	27,311
Proceeds from purchases of stock under employee stock purchase plan	7,664
Taxes paid related to net share settlement of stock-based awards	(93)
Repurchase of shares	0
Net cash provided by financing activities	41,986
Foreign currency effect on cash and cash equivalents	(230)
Net change in cash and cash equivalents	4,556
Cash and cash equivalents—Beginning of period	142,322
Cash and cash equivalents—End of period	$ 146,878

Revenue - Summary of Total Reve

Revenue - Summary of Total Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenues	$ 84,970	$ 61,377
U.S.
Disaggregation Of Revenue [Line Items]
Revenues	78,382	57,917
Non-U.S.
Disaggregation Of Revenue [Line Items]
Revenues	6,588	3,460
Subscription and Returns, Tax Determination | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	45,232	33,150
Subscription and Returns, Tax Returns and Compliance Management | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	26,686	21,800
Subscription and Returns,Interest Income on Funds Held for Customers | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	729	0
Subscription and Returns
Disaggregation Of Revenue [Line Items]
Revenues	78,231	57,870
Subscription and Returns | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	72,647	54,950
Professional Services
Disaggregation Of Revenue [Line Items]
Revenues	6,739	3,507
Professional Services | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	$ 5,735	$ 2,967

Revenue - Summary of Activity I

Revenue - Summary of Activity Impacting Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Contract Liabilities [Rollforward]
Balance at December 31, 2018	$ 0
Balance at March 31, 2019	4,208
Accrued Liabilities, Current
Contract Liabilities [Rollforward]
Balance at December 31, 2018	0
Contract liabilities transferred to deferred revenue	(1,257)
Addition to contract liabilities	3,375
Balance at March 31, 2019	$ 4,208
Accrued Liabilities, Current | ASU 2014-09
Contract Liabilities [Rollforward]
Adoption of ASC 606		$ 2,090

Revenue - Summary of Activity_2

Revenue - Summary of Activity Impacting Deferred Revenue (Details) - Deferred Revenue - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Deferred Revenue Rollforward
Balance at December 31, 2018	$ 134,653
Revenue recognized	(84,970)
Additional amounts deferred	94,281
Balance at March 31, 2019	$ 132,714
ASU 2014-09
Deferred Revenue Rollforward
Adoption of ASC 606		$ (11,250)

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred commissions amotization expected period	6 years
Deferred contract costs, expected to be amortized within next 12 Months	$ 6,062,000	$ 4,464,000	$ 0
Impairments of deferred contract costs	0
Assets recognized related to costs to fulfill contracts	0
Additional contractual obligations	32,200,000
Prepaid Expenses and Other Current Assets
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Deferred contract costs, expected to be amortized within next 12 Months	$ 6,100,000

Revenue - Summary of Activity_3

Revenue - Summary of Activity Impacting Deferred Commissions (Details) - Deferred Commissions - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Capitalized Contract Cost [Line Items]
Balance at December 31, 2018	$ 0
Additional commissions deferred	7,656
Amortization of deferred commissions	(1,279)
Balance at March 31, 2019	$ 25,644
ASU 2014-09
Capitalized Contract Cost [Line Items]
Adoption of ASC 606		$ 19,267

Revenue - Additional Informat_2

Revenue - Additional Information (Details 1) $ in Millions	Mar. 31, 2019USD ($)
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Additional contractual obligations	$ 32.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-03-31
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Additional contractual obligations	$ 31.9
Revenue expected to be recognized with remaining amount	12 months

Intangible Assets - Schedule of

Intangible Assets - Schedule of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Gross	$ 56,087	$ 47,341
Accumulated Amortization	(29,647)	(27,970)
Net	26,440	19,371
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross	18,652	15,412
Accumulated Amortization	(9,694)	(9,202)
Net	$ 8,958	$ 6,210
Customer Relationships | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	3 years	3 years
Customer Relationships | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	10 years	10 years
Developed Technology
Finite Lived Intangible Assets [Line Items]
Gross	$ 36,314	$ 30,935
Accumulated Amortization	(18,976)	(17,806)
Net	$ 17,338	$ 13,129
Developed Technology | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	3 years	3 years
Developed Technology | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	8 years	8 years
Noncompete Agreements
Finite Lived Intangible Assets [Line Items]
Gross	$ 669	$ 574
Accumulated Amortization	(554)	(542)
Net	$ 115	$ 32
Noncompete Agreements | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	3 years	3 years
Noncompete Agreements | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	5 years	5 years
Tradename and Trademarks
Finite Lived Intangible Assets [Line Items]
Gross	$ 452	$ 420
Accumulated Amortization	(423)	(420)
Net	$ 29	$ 0
Tradename and Trademarks | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	1 year	1 year
Tradename and Trademarks | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	4 years	4 years

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) shares in Thousands	Oct. 31, 2018USD ($)	May 31, 2018USD ($)	Mar. 31, 2019USD ($)Unit	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)shares
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, amortization expense			$ 1,700,000	$ 1,400,000
Cash payment to sellers			$ 131,000	$ 0
Number of goodwill impairment reporting units | Unit			3
Goodwill impairment charge	$ 0
Goodwill			$ 78,842,000		$ 61,300,000
Brazilian Reporting Unit
Finite Lived Intangible Assets [Line Items]
Goodwill			0
Tradestream Technologies Inc. and Wise 24 Inc
Finite Lived Intangible Assets [Line Items]
Future revenue recognized period		6 years
Cash payment to sellers			$ 100,000
Common stock Issue | shares					1,634
Tradestream Technologies Inc. and Wise 24 Inc | Maximum
Finite Lived Intangible Assets [Line Items]
Total consideration		$ 30,000,000

Intangible Assets - Schedule _2

Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Goodwill [Line Items]
Balance—December 31, 2018	$ 61,300
Cumulative translation adjustments	(218)
Balance—March 31, 2019	78,842
Compli, Inc.
Goodwill [Line Items]
Goodwill acquired during period	12,807
Indix Corporation
Goodwill [Line Items]
Goodwill acquired during period	$ 4,953

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Loss Contingencies [Line Items]
Rent expense	$ 3,000,000	$ 2,300,000
Sublease income	$ 400,000	$ 0
Loss contingency, inestimable loss	The Company has not recorded an accrual related to these arrangements as of March 31, 2019 because it has not determined that a loss is probable.
Maximum
Loss Contingencies [Line Items]
Estimated range of loss	$ 2,000,000

Debt - Additional Information (

Debt - Additional Information (Details) - Revolving Credit Facility - Loan and Security Agreement - Silicon Valley Bank and Ally Bank	3 Months Ended
	Mar. 31, 2019USD ($)
Line Of Credit Facility [Line Items]
Credit facilities amount	$ 50,000,000
Credit facilities, repayment month and year	2019-11
Quarterly fee on undrawn portion available under credit facilities	0.50%
Borrowings outstanding	$ 0
Maximum
Line Of Credit Facility [Line Items]
Credit facilities, interest rate	4.25%
Prime Rate | Maximum
Line Of Credit Facility [Line Items]
Credit facilities, variable rate	1.75%

Convertible Preferred Stock a_3

Convertible Preferred Stock and Shareholders' Equity - Additional Information (Details) $ / shares in Units, $ in Thousands	Jun. 14, 2018USD ($)$ / sharesshares	Mar. 31, 2019USD ($)Class$ / sharesshares	Mar. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2018$ / sharesshares
Class Of Stock [Line Items]
Number of classes of stock | Class		2
Capital stock, authorized shares	260,290,986	620,000,000
Common stock, shares authorized	153,944,895	600,000,000		600,000,000
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001		$ 0.0001
Convertible preferred stock, shares authorized	106,346,091
Convertible preferred stock, par value | $ / shares	$ 0.0001
Preferred stock, shares authorized		20,000,000		20,000,000
Preferred stock, par value | $ / shares		$ 0.0001		$ 0.0001
Description of IPO transaction		There were no changes to the rights and preferences of the common stock as a result of the IPO.
Fair value of shares repurchased | $			$ 752
Stock-based compensation cost | $		$ 6,571	3,517
Common Stock
Class Of Stock [Line Items]
Number of warrants net exercised to common stock		144,945
Common Stock Warrants
Class Of Stock [Line Items]
Number of warrants exercised	363,000
Proceeds from exercise of warrants | $	$ 3,700
Number of warrants outstanding		0
Employees and Non-Employee Investors
Class Of Stock [Line Items]
Fair value of shares repurchased | $			$ 800
Board of Directors | Common Stock Warrants
Class Of Stock [Line Items]
Number of common stock warrants issued		0	80,000
Common stock warrants, weighted average exercise price, per share | $ / shares			$ 16.60
Board of Directors | Common Stock Warrants | General and Administrative
Class Of Stock [Line Items]
Stock-based compensation cost | $			$ 500

Convertible Preferred Stock a_4

Convertible Preferred Stock and Shareholders' Equity - Summary of Changes of Convertible Preferred Stock and Shareholders' Equity (Deficit) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Class Of Stock [Line Items]
Beginning balance	$ 109,553	$ (393,592)	$ (393,592)
Impact of adoption of new accounting pronouncements (see Note 2)	27,622
Exercise of stock options	$ 27,311	6,025
Exercise of stock options, Shares	2,763,291
Shares tendered for cashless redemption of stock options	$ (93)	(7,715)
Stock-based compensation cost	6,571	3,517
Shares issued under employee stock purchase plan	7,664
Shares issued to purchase intangible assets	50	0
Repurchase of shares		(752)
Gain (Loss) on translation adjustment	(462)	603
Net loss	(9,243)	(15,249)
Ending balance	168,973	$ (407,163)	$ 109,553
Convertible Preferred Stock
Class Of Stock [Line Items]
Beginning balance, Shares		101,786,205	101,786,205
Beginning balance		$ 370,921	$ 370,921
Repurchase of shares, Shares		(10,000)
Repurchase of shares		$ (67)
Ending balance, Shares		101,776,205
Ending balance		$ 370,854
Common Stock
Class Of Stock [Line Items]
Beginning balance	$ 7	$ 1	$ 1
Beginning balance, Shares	66,768,563	5,992,293	5,992,293
Exercise of stock options, Shares	2,763,291	785,991
Shares tendered for cashless redemption, Shares	(2,805)	(465,710)
Shares issued under employee stock purchase plan, Shares	372,764
Shares issued to purchase intangible assets, Shares	1,634
Repurchase of shares, Shares		(48,152)
Ending balance	$ 7	$ 1	$ 7
Ending balance, Shares	69,903,447	6,264,422	66,768,563
Additional Paid-In Capital
Class Of Stock [Line Items]
Beginning balance	$ 599,493	$ 18,121	$ 18,121
Exercise of stock options	27,311	6,025
Shares tendered for cashless redemption of stock options	(93)	(7,715)
Stock-based compensation cost	6,571	3,517
Shares issued under employee stock purchase plan	7,664
Shares issued to purchase intangible assets	50
Repurchase of shares		(752)
Ending balance	640,996	19,196	599,493
Accumulated Other Comprehensive Income (Loss)
Class Of Stock [Line Items]
Beginning balance	(2,345)	338	338
Gain (Loss) on translation adjustment	(462)	603
Ending balance	(2,807)	941	(2,345)
Accumulated Deficit
Class Of Stock [Line Items]
Beginning balance	(487,602)	(412,052)	(412,052)
Impact of adoption of new accounting pronouncements (see Note 2)	27,622
Net loss	(9,243)	(15,249)
Ending balance	$ (469,223)	$ (427,301)	$ (487,602)

Equity Incentive Plans - Additi

Equity Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to outstanding awards	9,030,579		11,094,070
Total intrinsic value of options exercised	$ 109.5	$ 7
Weighted average grant date fair value of options granted	$ 17.93	$ 7.16
Number of shares, vested	773,467
Number of options unvested	4,286,235
Contractual life	10 years
Stock options, average vesting term	4 years
Expected term	6 years	6 years
Common stock, shares, issued	69,903,000		66,769,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation expense related to stock options	$ 37.5
Unrecognized compensation expense expected to be recognized over period	3 years
Stock options vesting period	4 years
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense expected to be recognized over period	4 years
Stock options vesting period	4 years
Total unrecognized compensation expense expected to be recognized	$ 41
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	5,315,780
Automatically increase percentage of aggregate number of shares of common stock outstanding	5.00%
Shares subject to outstanding awards	2,009,827
Shares available for future issuance	6,892,004
Number of shares of common stock reserved for issuance	5,315,780
2006 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to outstanding awards	8,039,077
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	996,709
Total unrecognized compensation expense related to stock options	$ 1.1
Contractual life	10 years
Expected term	6 months
Initial offering period	June 15, 2018
Description of offering period for ESPP	The first offering period began on June 15, 2018 and ended on January 31, 2019. Subsequent offering periods begin on August 1 and February 1 (or such other date determined by our Board of Directors or our Compensation and Leadership Development Committee).
Description of purchase price for shares of common stock purchased under ESPP	The purchase price for shares of common stock purchased under the ESPP is 85% of the lesser of the fair market value of the Company’s common stock on (i) the first day of the applicable offering period or (ii) the last day of the purchase period in the applicable offering period.
Percentage of purchase price for shares of common stock under fair value market	85.00%
Number of shares of common stock reserved for issuance	996,709
Employee stock purchase plan number of shares initially authorized	10,102,525
2018 Employee Stock Purchase Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Automatically increase percentage of aggregate number of shares of common stock outstanding	1.00%
Percentage of payroll deduction on eligible compensation	1.00%
Increase of common stock capital shares reserved for future issuance in each of calendar year	1,000,000
2018 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of payroll deduction on eligible compensation	15.00%
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares, issued	372,764

Equity Incentive Plans - Summar

Equity Incentive Plans - Summary of Stock-Based Compensation Expense Related to Equity Incentive Rewards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation cost	$ 6,571	$ 3,517
Common Stock Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation cost	0	512
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation cost	3,917	3,005
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation cost	1,698	0
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation cost	$ 956	$ 0

Equity Incentive Plans - Summ_2

Equity Incentive Plans - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Shares
Options outstanding beginning balance	11,094,070
Options granted	801,002
Options exercised	(2,763,291)
Options cancelled or expired	(101,202)
Options outstanding ending balance	9,030,579	11,094,070
Options exercisable	4,744,344
Weighted Average Exercise Price
Options outstanding beginning balance	$ 12.17
Options granted	41.41
Options exercised	9.89
Options cancelled or expired	14.96
Options outstanding ending balance	15.44	$ 12.17
Options exercisable	$ 9.54
Weighted Average Remaining Contractual Life (Years)
Options outstanding	7 years 1 month 6 days	6 years 9 months 21 days
Options exercisable	5 years 7 months 28 days
Aggregate Intrinsic Value
Options outstanding	$ 364,420	$ 210,523
Options exercisable	$ 219,420

Equity Incentive Plans - Summ_3

Equity Incentive Plans - Summary of Options Outstanding and Vested (Details)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Option Outstanding, Number Outstanding	9,030,579
Options Vested and Exercisable, Number Vested and Exercisable	4,744,344
Options Vested and Exercisable, Weighted Average Life (in Years)	5 years 7 months 28 days
$0.96 to 1.90
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Low | $ / shares	$ 0.96
Exercise Prices, High | $ / shares	$ 1.90
Option Outstanding, Number Outstanding	706,971
Options Outstanding, Weighted Average Life (in Years)	1 year 11 months 12 days
Options Vested and Exercisable, Number Vested and Exercisable	706,971
Options Vested and Exercisable, Weighted Average Life (in Years)	1 year 11 months 12 days
2.86 to 6.40
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Low | $ / shares	$ 2.86
Exercise Prices, High | $ / shares	$ 6.40
Option Outstanding, Number Outstanding	859,450
Options Outstanding, Weighted Average Life (in Years)	4 years 7 days
Options Vested and Exercisable, Number Vested and Exercisable	859,450
Options Vested and Exercisable, Weighted Average Life (in Years)	4 years 7 days
8.04 to 11.72
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Low | $ / shares	$ 8.04
Exercise Prices, High | $ / shares	$ 11.72
Option Outstanding, Number Outstanding	702,499
Options Outstanding, Weighted Average Life (in Years)	4 years 11 months 12 days
Options Vested and Exercisable, Number Vested and Exercisable	702,499
Options Vested and Exercisable, Weighted Average Life (in Years)	4 years 11 months 12 days
12.20 to 15.06
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Low | $ / shares	$ 12.20
Exercise Prices, High | $ / shares	$ 15.06
Option Outstanding, Number Outstanding	3,444,812
Options Outstanding, Weighted Average Life (in Years)	7 years 4 months 20 days
Options Vested and Exercisable, Number Vested and Exercisable	2,000,706
Options Vested and Exercisable, Weighted Average Life (in Years)	7 years 2 months 4 days
16.06 to 24.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Low | $ / shares	$ 16.06
Exercise Prices, High | $ / shares	$ 24
Option Outstanding, Number Outstanding	2,325,345
Options Outstanding, Weighted Average Life (in Years)	8 years 10 months 13 days
Options Vested and Exercisable, Number Vested and Exercisable	471,594
Options Vested and Exercisable, Weighted Average Life (in Years)	8 years 9 months 18 days
31.99 to 55.79
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices, Low | $ / shares	$ 31.99
Exercise Prices, High | $ / shares	$ 55.79
Option Outstanding, Number Outstanding	991,502
Options Outstanding, Weighted Average Life (in Years)	9 years 9 months 3 days
Options Vested and Exercisable, Number Vested and Exercisable	3,124
Options Vested and Exercisable, Weighted Average Life (in Years)	9 years 9 months 10 days

Equity Incentive Plans - Summ_4

Equity Incentive Plans - Summary of Fair Value Estimated Using Black-Scholes Option Pricing Model Assumptions (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair market value of common stock		$ 16.86
Volatility	40.00%	40.00%
Expected term	6 years	6 years
Expected dividend yield	0.00%	0.00%
Risk-free interest rate, minimum	2.31%
Risk-free interest rate, maximum	2.65%
Risk-free interest rate		2.55%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair market value of common stock	$ 39.76
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair market value of common stock	$ 55.79

Equity Incentive Plans - Summ_5

Equity Incentive Plans - Summary of RSU Activity (Details) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs outstanding as of December 31, 2018, Shares	74,424
RSUs granted, Shares	955,753
RSUs vested, Shares	0
RSUs cancelled, Shares	(11,852)
RSUs outstanding as of March 31, 2019, Shares	1,018,325
RSUs outstanding as of December 31, 2018, Weighted average grand date fair value per share | $ / shares	$ 32.69
RSUs granted, Weighted average grand date fair value per share | $ / shares	42.68
RSUs cancelled, Weighted average grand date fair value per share | $ / shares	39.76
RSUs outstanding as of March 31, 2019, Weighted average grand date fair value per share | $ / shares	$ 41.98

Equity Incentive Plans - Summ_6

Equity Incentive Plans - Summary of Grant Dare Fair Value of ESPP Estimated Using Black-Scholes Option Pricing Model Assumptions (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair market value of common stock		$ 16.86
Volatility	40.00%	40.00%
Expected term	6 years	6 years
Expected dividend yield	0.00%	0.00%
Risk-free interest rate		2.55%
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair market value of common stock	$ 40.60
Volatility	40.00%
Expected term	6 months
Expected dividend yield	0.00%
Risk-free interest rate	2.59%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Percentage of effective income tax rate expense (benefit)	1.30%	(5.30%)
Deferred income tax benefit associated with goodwill		$ (0.9)

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Shareholders - Schedule of Computation of Basic and Diluted Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net loss attributable to common shareholders	$ (9,243)	$ (15,249)
Denominator:
Weighted-average common shares outstanding-basic	68,381	6,170
Dilutive effect of share equivalents resulting from stock options, restricted stock units, common stock warrants, and convertible preferred shares (as converted)	0	0
Weighted-average common shares outstanding-diluted	68,381	6,170
Net loss per common share, basic and diluted	$ (0.14)	$ (2.47)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Shareholders - Schedule of Potential Shares Not Included in the Computation of Diluted Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	10,882	62,724
Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	10,237	11,286
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	631	0
Employee Stock Purchase Plan Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	14	0
Common Stock | Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	0	549
Convertible Preferred Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	0	50,889