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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2018	Feb. 18, 2019	Jun. 30, 2018
Entity Information [Line Items]
Entity Registrant Name	WORKIVA INC
Entity Central Index Key	0001445305
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Amendment Flag	false
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 782.1
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		34,859,096
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		9,445,596

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 77,584	$ 60,333
Marketable securities	20,764	16,364
Accounts receivable, net of allowance for doubtful accounts of $956 and $388 at December 31, 2018 and December 31, 2017, respectively	65,107	28,800
Deferred commissions	8,178	2,376
Other receivables	1,181	975
Prepaid expenses and other	4,417	6,444
Total current assets	177,231	115,292
Property and equipment, net	41,468	40,444
Deferred commissions, non-current	10,569	0
Intangible assets, net	1,266	1,118
Other assets	577	861
Total assets	231,111	157,715
Current liabilities
Accounts payable	5,461	3,060
Accrued expenses and other current liabilities	36,353	20,429
Deferred revenue	148,545	104,684
Current portion of capital lease and financing obligations	1,222	1,168
Total current liabilities	191,581	129,341
Deferred revenue, non-current	25,171	22,709
Other long-term liabilities	6,891	4,174
Capital lease and financing obligations	17,208	18,425
Total liabilities	240,851	174,649
Stockholders’ deficit
Preferred stock, $0.001 par value per share, 100,000,000 shares authorized, no shares issued and outstanding	0	0
Additional paid-in-capital	297,145	248,289
Accumulated deficit	(307,027)	(265,337)
Accumulated other comprehensive income	98	72
Total stockholders’ deficit	(9,740)	(16,934)
Total liabilities and stockholders’ deficit	231,111	157,715
Class A Common Stock
Stockholders’ deficit
Common stock	34	32
Class B Common Stock
Stockholders’ deficit
Common stock	$ 10	$ 10

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 956	$ 388
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	34,498,391	32,165,407
Common stock, shares outstanding	34,498,391	32,165,407
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	9,545,596	10,203,371
Common stock, shares outstanding	9,545,596	10,203,371

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Total revenue	$ 64,435	$ 60,873	$ 59,130	$ 59,906	$ 54,506	$ 52,068	$ 49,391	$ 51,904	$ 244,344	$ 207,869	$ 178,646
Cost of revenue
Total cost of revenue	17,394	15,659	16,296	16,511	16,089	15,652	14,286	14,218	65,860	60,245	51,625
Gross profit	47,041	45,214	42,834	43,395	38,417	36,416	35,105	37,686	178,484	147,624	127,021
Operating expenses
Research and development	20,773	19,984	20,718	20,127	18,870	17,527	16,239	15,536	81,602	68,172	57,438
Sales and marketing	23,011	24,068	22,252	21,006	21,949	23,712	19,787	18,713	90,337	84,161	80,466
General and administrative	11,047	11,864	21,654	11,768	12,271	8,959	8,943	9,421	56,333	39,594	32,695
Total operating expenses	54,831	55,916	64,624	52,901	53,090	50,198	44,969	43,670	228,272	191,927	170,599
Loss from operations	(7,790)	(10,702)	(21,790)	(9,506)	(14,673)	(13,782)	(9,864)	(5,984)	(49,788)	(44,303)	(43,578)
Interest expense	(480)	(448)	(449)	(450)	(451)	(464)	(475)	(455)	(1,827)	(1,845)	(1,875)
Other income, net	753	203	492	343	797	198	176	612	1,791	1,783	1,500
Loss before provision for income taxes	(7,517)	(10,947)	(21,747)	(9,613)	(14,327)	(14,048)	(10,163)	(5,827)	(49,824)	(44,365)	(43,953)
Provision for income taxes	204	17	21	5	(6)	25	33	9	247	61	24
Net loss	$ (7,721)	$ (10,964)	$ (21,768)	$ (9,618)	$ (14,321)	$ (14,073)	$ (10,196)	$ (5,836)	$ (50,071)	$ (44,426)	$ (43,977)
Net loss per common share:
Basic and diluted (in dollars per share)	$ (0.17)	$ (0.25)	$ (0.50)	$ (0.22)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (1.15)	$ (1.07)	$ (1.08)
Weighted-average common shares outstanding - basic and diluted (in shares)	44,472,672	43,973,428	43,234,655	42,858,756	42,108,764	41,815,139	41,429,691	41,108,611	43,640,408	41,618,838	40,671,133
Subscription and support
Revenue
Total revenue	$ 53,779	$ 51,306	$ 48,837	$ 46,470	$ 45,549	$ 43,214	$ 40,980	$ 39,540	$ 200,392	$ 169,283	$ 143,120
Cost of revenue
Total cost of revenue	8,637	8,139	8,637	8,802	8,779	8,472	7,758	7,637	34,215	32,646	27,895
Professional services
Revenue
Total revenue	10,656	9,567	10,293	13,436	8,957	8,854	8,411	12,364	43,952	38,586	35,526
Cost of revenue
Total cost of revenue	$ 8,757	$ 7,520	$ 7,659	$ 7,709	$ 7,310	$ 7,180	$ 6,528	$ 6,581	$ 31,645	$ 27,599	$ 23,730

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (50,071)	$ (44,426)	$ (43,977)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of income tax (expense) of (9), ($2), and ($13) for the years ended December 31, 2018, 2017 and 2016, respectively	26	(159)	18
Unrealized gain (loss) on available-for-sale securities, net of income tax (expense) benefit of $0, $2, and ($19) for the years ended December 31, 2018, 2017 and 2016, respectively	0	(60)	32
Other comprehensive income (loss), net of tax	26	(219)	50
Comprehensive loss	$ (50,045)	$ (44,645)	$ (43,927)

- Definition

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

+ References + Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, tax (expense) benefit	$ (9)	$ (2)	$ (13)
Unrealized gain on available-for-sale securities, tax benefit (expense)	$ 0	$ 2	$ (19)

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock (Class A and B)	Additional Paid-in-Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance at the beginning of the period (in shares) at Dec. 31, 2015		40,948,000
Beginning of the period at Dec. 31, 2015	$ 25,719	$ 41	$ 202,371	$ 241	$ (176,934)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	14,247		14,247
Issuance of common stock upon exercise of stock options (in shares)		374,000
Issuance of common stock upon exercise of stock options	1,597	$ 0	1,597
Tax withholdings related to net share settlements of stock-based compensation awards (in shares)		(61,000)
Tax withholdings related to net share settlements of stock-based compensation awards	(761)		(761)
Net loss	(43,977)				(43,977)
Other comprehensive income	50			50
Balance at the end of the period (in shares) at Dec. 31, 2016		41,261,000
End of the period at Dec. 31, 2016	(3,125)	$ 41	217,454	291	(220,911)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	19,476		19,476
Issuance of common stock upon exercise of stock options (in shares)		1,159,000
Issuance of common stock upon exercise of stock options	12,485	$ 1	12,484
Issuance of restricted stock units (in shares)		30,000
Tax withholdings related to net share settlements of stock-based compensation awards (in shares)		(81,000)
Tax withholdings related to net share settlements of stock-based compensation awards	(1,125)		(1,125)
Net loss	(44,426)				(44,426)
Other comprehensive income	(219)			(219)
Balance at the end of the period (in shares) at Dec. 31, 2017		42,369,000
End of the period at Dec. 31, 2017	(16,934)	$ 42	248,289	72	(265,337)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 30,841		30,841
Issuance of common stock upon exercise of stock options (in shares)	1,480,738	1,481,000
Issuance of common stock upon exercise of stock options	$ 16,662	$ 2	16,660
Issuance of common stock under employee stock purchase plan (in shares)		179,000
Issuance of common stock under employee stock purchase plan	3,216		3,216
Issuance of restricted stock units (in shares)		99,000
Tax withholdings related to net share settlements of stock-based compensation awards	(1,861)	$ (84)	(1,861)
Net loss	(50,071)				(50,071)
Other comprehensive income	26			26
Balance at the end of the period (in shares) at Dec. 31, 2018		44,044,000
End of the period at Dec. 31, 2018	$ (9,740)	$ 44	$ 297,145	$ 98	$ (307,027)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net loss	$ (50,071)	$ (44,426)	$ (43,977)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	3,781	3,546	3,820
Stock-based compensation expense	30,841	19,476	14,247
Provision for (recovery of) doubtful accounts	550	(517)	185
Realized gain on sale of available-for-sale securities, net	0	0	(6)
(Accretion) amortization of premiums and discounts on marketable securities, net	(141)	101	147
Recognition of deferred government grant obligation	0	(1,578)	(1,141)
Deferred income tax	(9)	0	(32)
Changes in assets and liabilities:
Accounts receivable	(20,216)	(5,546)	(7,101)
Deferred commissions	(11,155)	(498)	(497)
Other receivables	(205)	577	(732)
Prepaid expenses and other	2,020	2,952	(5,513)
Other assets	276	618	(654)
Accounts payable	1,699	2,206	(3,930)
Deferred revenue	40,144	29,367	34,211
Accrued expenses and other liabilities	8,886	(758)	604
Net cash provided by (used in) operating activities	6,400	5,520	(10,369)
Cash flows from investing activities
Purchase of property and equipment	(1,122)	(1,188)	(1,901)
Purchase of marketable securities	(24,659)	(14,369)	(1,301)
Maturities of marketable securities	20,400	9,281	0
Sale of marketable securities	0	0	7,197
Purchase of intangible assets	(251)	(197)	(190)
Net cash (used in) provided by investing activities	(5,632)	(6,473)	3,805
Cash flows from financing activities
Proceeds from option exercises	16,662	12,485	1,597
Taxes paid related to net share settlements of stock-based compensation awards	(1,861)	(1,125)	(761)
Proceeds from shares issued in connection with employee stock purchase plan	3,216	0	0
Repayment of other long-term debt	0	(73)	(18)
Principal payments on capital lease and financing obligations	(1,163)	(1,435)	(1,863)
Proceeds from government grants	22	51	183
Deferred financing costs	0	(81)	(33)
Net cash provided by (used in) financing activities	16,876	9,822	(895)
Effect of foreign exchange rates on cash	(393)	183	(10)
Net increase (decrease) in cash and cash equivalents	17,251	9,052	(7,469)
Cash and cash equivalents at beginning of year	60,333	51,281	58,750
Cash and cash equivalents at end of year	77,584	60,333	51,281
Supplemental cash flow disclosure
Cash paid for interest	1,734	1,627	1,835
Cash paid for income taxes, net of refunds	67	42	47
Supplemental disclosure of noncash investing and financing activities
Allowance for tenant improvements	2,192	0	481
Purchases of property and equipment, accrued but not paid	$ 1,287	$ 0	$ 0

Organization and Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Significant Accounting Policies

Organization

Workiva Inc., a Delaware corporation, and its wholly-owned subsidiaries (the “Company” or “we” or “us”) is a leading provider of cloud-based solutions for connected data, reporting and compliance. Our platform, Wdesk, is used by thousands of public and private companies, government agencies and higher-education institutions. Wdesk offers controlled collaboration, data linking, data integrations, granular permissions, process management and a full audit trail. We sell to customers in the areas of: finance and accounting; risk and controls; regulatory reporting; financial close, management and performance reporting; and statutory and corporate tax reporting. Our operational headquarters are located in Ames, Iowa, with additional offices located in the United States, Europe, the Asia-Pacific region and Canada.

Basis of Presentation and Principles of Consolidation

The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles and include the accounts of Workiva Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Additionally, certain prior year amounts have been reclassified for consistency with the current year presentation. The reclassification of the prior period amounts were not material to the previously reported consolidated financial statements.

Seasonality has affected our revenue, expenses and cash flows from operations. Revenue from professional services has been higher in the first quarter as many of our customers file their 10-K in the first calendar quarter. Sales and marketing expense has been higher in the third quarter due to our annual user conference in September. In addition, the timing of the payments for cash bonuses to employees during the first and fourth calendar quarters may result in some seasonality in operating cash flow.

Foreign Currency

We translate the financial statements of our foreign subsidiaries, which have a functional currency in the respective country’s local currency, to U.S. dollars using month-end exchange rates for assets and liabilities and average exchange rates for revenue, costs and expenses. Translation gains and losses are recorded in accumulated other comprehensive income as a component of stockholders’ deficit. Gains and losses resulting from foreign currency transactions that are denominated in currencies other than the entity's functional currency are included within “Other income, net” on the consolidated statements of operations. We recorded $289,000, $(372,000) and $67,000 of transaction gains (losses) during the years ended December 31, 2018, 2017 and 2016, respectively.

Use of Estimates

The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States requires us to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. We base our estimates on historical experience and various other assumptions believed to be reasonable. These estimates include, but are not limited to, the allowance for doubtful accounts, the determination of the relative selling prices of our services, the measurement of material rights, health insurance claims incurred but not yet reported, valuation of available-for-sale marketable securities, useful lives of deferred contract costs, intangible assets and property and equipment, income taxes and certain assumptions used in the valuation of equity awards. While these estimates are based on our best knowledge of current events and actions that may affect us in the future, actual results may differ materially from these estimates.

Cash and Cash Equivalents

Cash consists of cash on deposit with banks that is stated at cost, which approximates fair value. We invest our excess cash primarily in highly liquid money market funds and marketable securities. We classify all highly liquid investments with stated maturities of three months or less from date of purchase as cash equivalents and all highly liquid investments with stated maturities of greater than three months as marketable securities.

Marketable Securities

Our marketable securities consist of commercial paper, U.S. corporate debt securities, and U.S. treasury debt securities. We classify our marketable securities as available-for-sale at the time of purchase and reevaluate such classification as of each balance sheet date. We may sell these securities at any time for use in current operations even if they have not yet reached maturity. As a result, we classify our investments, including securities with maturities beyond twelve months as current assets in the accompanying consolidated balance sheets. Available-for-sale securities are recorded at fair value each reporting period. Unrealized gains and losses are excluded from earnings and recorded as a separate component within “Accumulated other comprehensive income” on the consolidated balance sheets until realized. Dividend income is reported within “Other income, net” on the consolidated statements of operations. We evaluate our investments to assess whether those with unrealized loss positions are other than temporarily impaired. We consider impairments to be other than temporary if they are related to deterioration in credit risk or if it is likely we will sell the securities before the recovery of their cost basis. Realized gains and losses and declines in value judged to be other than temporary are determined based on the specific identification method and are reported in “Other income, net” on the consolidated statements of operations.

Fair Value of Financial Instruments

Our financial assets, which include cash equivalents and marketable securities, are measured and recorded at fair value on a recurring basis. Our other current financial assets and our other current financial liabilities have fair values that approximate their carrying value due to their short-term maturities.

Concentration of Credit Risk

Our accounts receivable are derived primarily from customers located in North America. We perform ongoing credit evaluations of our customers’ financial condition and require no collateral from our customers. We maintain an allowance for doubtful accounts receivable based upon the expected collectability of accounts receivable balances. We did not have a significant concentration of accounts receivable from any single customer or from customers in any single country outside of the United States at December 31, 2018 or 2017.

Deferred Commissions

Sales commissions earned by our sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions paid where the amortization period is one year or less are expensed as incurred. All other sales commissions are deferred and then amortized on a straight-line basis over a period of benefit that we have determined to be three years. We determined the period of benefit by taking into consideration our standard contract terms and conditions, rate of technological change and other factors. Amortization expense is included in sales and marketing expense in the accompanying consolidated statements of operations.

Property and Equipment, net

Property and equipment is stated at cost, net of accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, generally three to ten years. We amortize leasehold improvements and assets under capital leases or financing arrangements over the lesser of the term of the lease including renewal options that are reasonably assured or the estimated useful life of the assets. Depreciation and amortization expense totaled $3.4 million, $3.4 million and $3.7 million for the years ended December 31, 2018, 2017 and 2016, respectively, and included $1.3 million, $1.6 million and $2.1 million of amortization of assets recorded under capital leases during the years ended December 31, 2018, 2017 and 2016, respectively.

Revenue Recognition

We generate revenue through the sale of subscriptions to our cloud-based software and the delivery of professional services. We recognize revenue when control of these services is transferred to our customers in an amount that reflects the consideration we expect to be entitled to in exchange for those services.

We determine revenue recognition through the following steps:

•Identification of the contract, or contracts, with a customer

•Identification of the performance obligations in the contract

•Determination of the transaction price

•Allocation of the transaction price to the performance obligations in the contract

•Recognition of revenue when, or as, we satisfy a performance obligation

We report revenue net of sales and other taxes collected from customers to be remitted to government authorities.

Subscription and Support Revenue

We recognize subscription and support revenue on a ratable basis over the contract term beginning on the date that our service is made available to the customer. Our subscription contracts are generally three to 36 months in duration, are billed in advance and are non-cancelable. We consider the access to Wdesk and related support services in a customer contract to be a series of distinct services which comprise a single performance obligation because they are substantially the same and have the same pattern of transfer.

Professional Services Revenue and Customer Options

Professional services revenues primarily consist of fees for document set up, XBRL tagging, and consulting with our customers on business processes and best practices for using Wdesk. We have determined that an agreement to purchase these professional services constitutes an option to purchase services in accordance with ASC 606 rather than an agreement that creates enforceable rights and

obligations because of the customer's contractual right to cancel services that have not yet been used. In the limited case of agreements where we determined that the option provides the customer with a material right, we allocate a portion of the transaction price to the material right. Professional service agreements that do not contain a material right are accounted for when the customer exercises its option to purchase additional services. Revenue is recognized for document set ups when the service is complete and control has transferred to the customer. Revenues from XBRL tagging and consulting services are recognized as the services are performed.

Contracts with Multiple Performance Obligations

Some of our contracts with customers contain multiple performance obligation in the event that we determine a material right exists. For these contracts, we account for the individual performance obligations separately when they are both capable of being distinct, whereby the customer can benefit from the service either on its own or together with other resources that are readily available from third parties or from us, and are distinct in the context of the contract, whereby the transfer of the services is separately identifiable from other promises in the contract. If these criteria are not met, the promised services are accounted for as a combined performance obligation. The transaction price is allocated to the separate performance obligations on a relative standalone selling price basis. We determine the standalone selling prices based on our overall pricing objectives, taking into consideration market conditions and entity-specific factors, including the size of our arrangements, length of term, customer demographics and the numbers and types of users within our arrangements.

Deferred Revenue

We typically invoice our customers for subscription and support fees in advance on a quarterly, annual, two- or three-year basis, with payment due at the start of the subscription term. Unpaid invoice amounts for non-cancelable services starting in future periods are included in accounts receivable and deferred revenue. The portion of deferred revenue that we anticipate will be recognized after the succeeding twelve-month period is recorded as non-current deferred revenue, and the remaining portion is recorded as current deferred revenue.

Customer Deposits

As an agreement to purchase professional services constitutes a customer option, fees received in advance of these services being performed are considered customer deposits and are included in accrued expenses and other current liabilities on the consolidated balance sheets. Unpaid invoice amounts for these professional services starting in future periods are excluded from accounts receivable and accrued expenses and other current liabilities.

Cost of Revenue

Cost of revenue consists primarily of personnel and related costs directly associated with the professional services and customer success teams and training personnel, including salaries, benefits, bonuses, and stock-based compensation; the costs of contracted third-party vendors; the costs of server usage by our customers; information technology costs; and facility costs.

Sales and Marketing Expenses

Sales and marketing expenses consist primarily of personnel and related costs, including salaries, benefits, bonuses, commissions, travel, and stock-based compensation. Other costs included in this expense are marketing and promotional events, our annual user conference, online marketing, product marketing, information technology costs, and facility costs.

Advertising costs are charged to sales and marketing expense as incurred. Advertising expense totaled $2.9 million, $2.7 million and $2.7 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Research and Development Expenses

Research and development expenses consist primarily of personnel and related costs, including salaries, benefits, bonuses, and stock-based compensation, costs of server usage by our developers, information technology costs, and facility costs.

General and Administrative Expenses

General and administrative expenses consist primarily of personnel and related costs for our executive, finance, legal, human resources, and administrative personnel, including salaries, benefits, bonuses, and stock-based compensation; legal, accounting, and other professional service fees; other corporate expenses; information technology costs; and facility costs.

Leases

We categorize leases at their inception as either operating or capital leases and may receive renewal or expansion options, rent holidays, and leasehold improvement and other incentives on certain lease agreements. We recognize lease costs on a straight-line basis, taking into account adjustments for free or escalating rental payments, renewals at our option that are reasonably assured and deferred payment terms. Additionally, lease incentives are accounted for as a reduction of lease costs over the term of the agreement.

Government Grants

Government grants received are recorded as a liability on the balance sheets until all contingencies are resolved and the grant is determined to be realized.

Intangible Assets

We account for intangible assets under Accounting Standards Codification (ASC) 350, Goodwill and Other. Intangible assets consist of legal fees incurred for patents and are recorded at cost and amortized over the useful lives of the assets of ten years, using the straight-line method. Certain patents are in the legal application process and therefore are not currently being amortized.

Accumulated amortization of patents as of December 31, 2018 and 2017 was approximately $320,000 and $218,000, respectively. Future amortization expense for legally approved patents is estimated at $113,000 per year through 2022, $96,000 in 2023 and approximately $217,000 thereafter.

Impairment of Long-Lived Assets

Long-lived assets, such as property, equipment, and software and intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. If circumstances require that a long-lived asset or asset group be tested for possible impairment, we first compare the undiscounted cash flows expected to be generated by that long-lived asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value.

Stock-Based Compensation

We measure all share-based payments, including grants of options to purchase common stock and the issuance of restricted stock or restricted stock units to employees, service providers and board members, using a fair-value based method. We record forfeitures as they occur. The cost of services received from employees and non-employees in exchange for awards of equity instruments is recognized in the consolidated statement of operations based on the estimated fair value of those awards on the grant date or reporting date, if required to be remeasured, and amortized on a straight-line basis over the requisite service period. We use the Black-Scholes option-pricing model to determine the fair values of stock option awards. For restricted stock and restricted stock units, fair value is based on the closing price of our common stock on the grant date.

Income Taxes

We record current income taxes based on our estimates of current taxable income and provide for deferred income taxes to reflect estimated future income tax payments and receipts. We are subject to U.S. federal income taxes as well as state taxes. In addition, we are subject to taxes in the foreign jurisdictions where we operate.

We account for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, we determine deferred tax assets and liabilities on the basis of the differences between the financial statement and tax bases of assets and liabilities by using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment rate.

On December 22, 2017, the U.S. federal government enacted legislation commonly referred to as the “Tax Cuts and Jobs Act” (the “TCJA”). The TCJA made widespread changes to the Internal Revenue Code, including, among other items, the introduction of a new international “Global Intangible Low-Taxed Income” (“GILTI”) regime effective January 1, 2018. Companies may adopt one of two views in regards to establishing deferred taxes in accordance with the new (“GILTI”) regime under ASC 740. Companies may account for the effects of GILTI either (1) in the period the entity becomes subject to GILTI, or (2) establish deferred taxes (similar to the guidance that currently exists with respect to basis differences that will reverse under current Subpart F rules) for basis differences that upon reversal will be subject to GILTI. We have elected to account for GILTI in the period incurred.

We recognize deferred tax assets to the extent that we believe that these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and results of recent operations. If we determine that we would be able to realize our deferred tax assets in the future in excess of their net recorded amount, we would make an

adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

We record uncertain tax positions in accordance with ASC 740, Income Taxes, on the basis of a two-step process in which (1) we determine whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not threshold, we recognize the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority.

We recognize interest and penalties related to unrecognized tax benefits on the income tax expense line in the accompanying consolidated statements of operations. Accrued interest and penalties are included on the related tax liability line in the consolidated balance sheets.

Accounts Receivable and Allowance for Doubtful Accounts

Accounts receivable are recorded at the invoiced amount net of an allowance for doubtful accounts. The allowance for doubtful accounts is based on our assessment of the collectability of customer accounts. We regularly review our receivables that remain outstanding past their applicable payment terms and established an allowance for potential write-offs by considering factors such as historical experience, credit quality, age of the accounts receivable balances, and current economic conditions that may affect a customer’s ability to pay. Accounts receivable deemed uncollectible are charged against the allowance once collection efforts have been exhausted.

Recently Adopted Accounting Pronouncements

In May 2014, the FASB issued guidance codified in ASC 606, Revenue Recognition - Revenue from Contracts with Customers (ASU 2014-09), which amends the guidance in former ASC 605, Revenue Recognition. The core principle of ASC 606 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Additionally, the guidance requires improved disclosures to help users of financial statements better understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

Effective January 1, 2018, we adopted ASU 2014-09 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. We recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of our accumulated deficit. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods.

The primary impact on accounts receivables and deferred revenue of adopting the new standard relates to recording deferred revenue when payments are due in advance of our performance of subscription based contracts. This recording has resulted in an offsetting increase in accounts receivable and deferred revenue.

The effect of adopting the new standard on accrued expenses and other current liabilities relates to the reclassification of amounts collected in advance related to the purchase of professional services from deferred revenue to accrued expenses and other current liabilities as these agreements to purchase professional services constitute a customer option.

The primary impact of adopting the new standard on sales and marketing expense relates to the deferral of incremental commission costs of obtaining subscription contracts. Under the previous guidance, we deferred only direct and incremental commission costs to obtain a contract and amortized those costs on a straight-line basis over the lesser of 12 months or the non-cancelable term of the customer contract based on the terms of our commission arrangements. Under the new standard, we defer all incremental commission costs to obtain the contract. We amortize these costs on a straight-line basis over a period of benefit that we have determined to be three years.

The adoption of ASC 606 primarily resulted in an acceleration of revenue as of December 31, 2017, which in turn reduced our existing deferred tax asset for amounts that had previously been included in deferred revenue. Additionally, the amortization of the costs of obtaining a contract has generated additional deferred tax liabilities that ultimately reduced our net deferred tax asset position. As we have provided a full valuation allowance against our net deferred tax assets in the jurisdictions impacted by the adoption of ASC 606, this aggregate impact was offset by a corresponding reduction to the valuation allowance.

The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of ASU 2014-09 were as follows (in thousands):


	As of December 31, 2017		Adjustments Due to ASU 2014-09		As of January 1, 2018
Assets
Accounts receivable, net	$	28,800	$	16,900	$	45,700
Deferred commissions	2,376		650		3,026
Deferred commissions, non-current	—		4,655		4,655

Liabilities
Accrued expenses and other current liabilities	20,429		6,956		27,385
Deferred revenue	104,684		6,625		111,309
Deferred revenue, non-current	22,709		243		22,952

Equity
Accumulated deficit	$	(265,337)	$	8,381	$	(256,956)

In accordance with the new revenue standard requirements, the impact of adoption on our consolidated balance sheet as of December 31, 2018 and statement of operations for the year ended December 31, 2018 was as follows (in thousands, except per share data):


	As of December 31, 2018
	As Reported	Balances Without Adoption of ASC 606	Effect of Change
Assets
Accounts receivable, net	65,107	37,528	27,579
Deferred commissions	8,178	4,593	3,585
Deferred commissions, non-current	10,569	—	10,569

Liabilities
Accrued expenses and other current liabilities	36,353	28,958	7,395
Deferred revenue	148,545	134,793	13,752
Deferred revenue, non-current	25,171	20,853	4,318

Equity
Accumulated deficit	(307,027)	(323,295)	16,268


	Year ended December 31, 2018
	As Reported		Balances Without Adoption of ASC 606		Effect of Change
Revenues
Subscription and support	$	200,392	$	199,575	$	817
Professional services	43,952		45,707		(1,755)

Operating expenses
Sales and marketing	90,337		99,162		(8,825)

Net loss	$	(50,071)	$	(57,958)	$	7,887

Net loss per common share
Basic and diluted	$	(1.15)	$	(1.33)	$	0.18

The adoption of ASC 606 had no impact on our total cash flows from operations.

In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting. This ASU clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The ASU is effective for annual periods beginning after December 15, 2017 and interim periods within those annual periods. Effective January 1, 2018, we adopted this standard. The adoption of this guidance did not have a material impact on our consolidated financial statements.

In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. This ASU simplifies the accounting for nonemployee share-based payment transactions. Under the new guidance, equity-classified share-based payment awards issued to nonemployees will now be measured on the grant date, instead of the previous requirement to remeasure the awards through performance completion date. Awards that include performance conditions will recognize compensation cost when the achievement of the performance condition is probable, rather than upon achievement of the performance condition. Finally, the current requirement to reassess the classification (equity or liability) for nonemployee awards upon vesting will be eliminated, except for awards in the form of convertible instruments. The ASU is effective for annual periods beginning after December 15, 2018 and interim periods within those annual periods. Early adoption is permitted, including interim periods, but no earlier than the adoption of ASC 606. Effective June 20, 2018, we adopted this standard. The adoption of this new guidance did not have a material impact on our consolidated financial statements.

New Accounting Pronouncements Not Yet Adopted

In February 2016, the FASB issued guidance codified in ASC 842, Leases, which supersedes the guidance in former ASC 840, Leases, to increase transparency and comparability among organizations by requiring recognition of right-of-use assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements (with the exception of short-term leases). The standard will become effective for interim and annual periods beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements that allows entities to recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We plan to adopt this guidance on January 1, 2019 using this new transition guidance.

We currently expect to use the package of practical expedients which allows us to not (1) reassess whether any expired or existing contracts are considered or contain leases; (2) reassess the lease classification for any expired or existing leases; and (3) reassess the initial direct costs for any existing leases.

In the fourth quarter of 2018, we substantially completed our project plan to apply the necessary changes to accounting processes, procedures and internal controls, and we plan to finalize our transition adjustment under ASC 842 in the first quarter of 2019. We expect the adoption will result in the addition of approximately $16.0 million of assets and liabilities to our consolidated balance sheet, with no significant changes to our consolidated statements of operations or cash flows.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which amends the current accounting guidance and requires the measurement of all expected losses based on historical experience, current conditions and reasonable and supportable forecasts. For trade receivables, loans, and other financial instruments, we will be required to use a forward-looking expected loss model rather than the incurred loss model for recognizing credit losses which reflects losses that are probable. The standard will become effective for

interim and annual periods beginning after December 15, 2019, with early adoption permitted. Application of the amendments is through a cumulative-effect adjustment to retained earnings as of the effective date. We plan to adopt this standard on the effective date and are currently evaluating the impact of this new standard on our consolidated financial statements.

In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which clarifies the accounting for implementation costs in cloud computing arrangements. The update will become effective for interim and annual periods beginning after December 15, 2019 and may be adopted either retrospectively or prospectively. Early adoption is permitted. We plan to adopt this standard prospectively on the effective date. We are currently evaluating the impacts that adoption of this ASU will have on our consolidated financial statements.

Cash Equivalents and Marketable Securities

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Cash Equivalents and Marketable Securities

At December 31, 2018, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
Money market funds	$	52,068	$	—	$	—	$	52,068
Commercial paper	7,448		—		—		7,448
U.S. treasury debt securities	2,494		—		(1)		2,493
U.S. corporate debt securities	10,890		—		(67)		10,823
	$	72,900	$	—	$	(68)	$	72,832
Included in cash and cash equivalents	$	52,068	$	—	$	—	$	52,068
Included in marketable securities	$	20,832	$	—	$	(68)	$	20,764

At December 31, 2017, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
Money market funds	$	49,452	$	—	$	—	$	49,452
U.S. treasury debt securities	3,083		—		(8)		3,075
U.S. corporate debt securities	13,350		—		(61)		13,289
	$	65,885	$	—	$	(69)	$	65,816
Included in cash and cash equivalents	$	49,452	$	—	$	—	$	49,452
Included in marketable securities	$	16,433	$	—	$	(69)	$	16,364

The following table presents gross unrealized losses and fair values for those marketable securities that were in an unrealized loss position as of December 31, 2018, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in thousands):


	As of December 31, 2018
	Less than 12 months						12 months or greater
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. treasury debt securities	$	—	$	—	$	998	$	(1)
U.S. corporate debt securities	3,481		(5)		7,342		(62)
Total	$	3,481	$	(5)	$	8,340	$	(63)

We do not believe any of the unrealized losses represented an other-than-temporary impairment based on our evaluation of available evidence, which includes our intent as of December 31, 2018 to hold these investments until the cost basis is recovered.

Supplemental Consolidated Balance Sheet and Statement of Operations Information

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Supplemental Consolidated Balance Sheet and Statement of Operations Information

Property and Equipment, net

Property and equipment, net as of December 31, 2018 and 2017 consisted of (in thousands):


	As of December 31,
	2018		2017
Buildings	$	36,608	$	36,608
Computers, equipment and software	6,602		6,277
Furniture and fixtures	8,839		8,428
Vehicles	97		97
Leasehold improvements	7,678		4,669
Construction in process	15		—
	59,839		56,079
Less: accumulated depreciation and amortization	(18,371)		(15,635)
	$	41,468	$	40,444

The following assets included in property and equipment, net were acquired under capital and financing leases (see Note 6) (in thousands):


	As of December 31,
	2018		2017
Buildings	$	36,608	$	36,608
Computers and equipment	—		666
	36,608		37,274
Less: accumulated amortization	(6,237)		(5,891)
	$	30,371	$	31,383

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities as of December 31, 2018 and 2017 consisted of (in thousands):


	As of December 31,
	2018		2017
Accrued vacation	$	6,906	$	6,087
Accrued commissions	7,265		3,297
Accrued bonuses	5,643		4,419
Estimated health insurance claims	1,100		1,090
ESPP employee contributions	2,156		1,419
Customer deposits	7,395		—
Accrued other liabilities	5,888		4,117
	$	36,353	$	20,429

Other Income, net

Other income, net for the years ended December 31, 2018, 2017 and 2016 consisted of (in thousands):


	For the year ended December 31,
	2018		2017		2016
Interest income	$	1,278	$	586	$	286
Income from training reimbursement program	—		1,578		1,141
Gains (losses) on foreign currency transactions	289		(372)		67
Other	224		(9)		6
	$	1,791	$	1,783	$	1,500

Fair Value Measurements

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

We determine the fair values of our financial instruments based on the fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. 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. The fair value assumes that the transaction to sell the asset or transfer the liability occurs in the principal or most advantageous market for the asset or liability and establishes that the fair value of an asset or liability shall be determined based on the assumptions that market participants would use in pricing the asset or liability. The classification of a financial asset or liability within the hierarchy is based upon the lowest level input that is significant to the fair value measurement. The fair value hierarchy prioritizes the inputs into three levels that may be used to measure fair value:

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 inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument.

Level 3 - Inputs are unobservable inputs based on our assumptions.

Financial Assets

Cash equivalents primarily consist of AAA-rated money market funds with overnight liquidity and no stated maturities. We classified cash equivalents as Level 1 due to the short-term nature of these instruments and measured the fair value based on quoted prices in active markets for identical assets.

When available, our marketable securities are valued using quoted prices for identical instruments in active markets. If we are unable to value our marketable securities using quoted prices for identical instruments in active markets, we value our investments using broker reports that utilize quoted market prices for comparable instruments. We validate, on a sample basis, the derived prices provided by the brokers by comparing their assessment of the fair values of our investments against the fair values of the portfolio balances of another third-party professional pricing service. As of December 31, 2018 and 2017, all of our marketable securities were valued using quoted prices for comparable instruments in active markets and are classified as Level 2.

Based on our valuation of our money market funds and marketable securities, we concluded that they are classified in either Level 1 or Level 2 and we have no financial assets measured using Level 3

inputs. The following table presents information about our assets that are measured at fair value on a recurring basis using the above input categories (in thousands):


	Fair Value Measurements as of December 31, 2018										Fair Value Measurements as of December 31, 2017
Description	Total		Level 1		Level 2		Total		Level 1		Level 2
Money market funds	$	52,068	$	52,068	$	—	$	49,452	$	49,452	$	—
Commercial paper	7,448		—		7,448		—		—		—
U.S. treasury debt securities	2,493		—		2,493		3,075		—		3,075
U.S. corporate debt securities	10,823		—		10,823		13,289		—		13,289
	$	72,832	$	52,068	$	20,764	$	65,816	$	49,452	$	16,364

Included in cash and cash equivalents	$	52,068					$	49,452
Included in marketable securities	$	20,764					$	16,364

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Deferred Costs	12 Months Ended
Deferred Costs	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Deferred Costs	Deferred CostsDeferred costs, which primarily consist of costs to obtain contracts with customers, were $18.7 million as of December 31, 2018. Amortization expense for the deferred costs was $10.1 million for the year ended December 31, 2018. There was no significant impairment loss in relation to the costs capitalized for the period presented.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Lease Commitments

We lease certain office and residential space under non-cancelable operating leases with various lease terms through June 2043. Rent expense for the years ended December 31, 2018, 2017 and 2016 was $5.6 million, $4.7 million and $3.9 million, respectively.

Build to Suit

We entered into a lease agreement for land and an office building in Ames, Iowa, which was constructed in two phases. As part of the lease agreement, the landlord was responsible for constructing the building in accordance with our specifications and agreed to fund $11.8 million for the first phase and $11.1 million for the second phase of construction. We were the developer of the project and responsible for construction costs in excess of these amounts. As a result of this involvement, we were deemed the “owner” for accounting purposes during the construction period and were required to capitalize the construction costs associated with the office building. Upon completion of each phase of the project, we performed a sale-leaseback analysis to determine if the building could be removed from the balance sheet. We determined there was continuing involvement, which precluded derecognition of the building. The construction liability of $11.8 million was reclassified to a financing obligation, and $17.1 million of costs capitalized during construction was placed in service during June 2013 for the initial phase. Upon completion of the second phase of the project, the construction liability of $11.1 million was reclassified to a financing obligation, and $19.9 million of costs capitalized during construction was placed in service during 2014.

Total cash payments due under the arrangement were allocated on a relative fair value basis between rent related to the land lease and debt service payments related to the financing obligation. The portion of the lease payments allocated to the land is expensed on a straight-line basis over the term of the lease from the point we took possession of the land and including renewal periods where renewal was deemed reasonably assured at the inception of the lease. The lease contains purchase options to acquire

the landlord’s interest in the land lease and building at any time beginning three years from the commencement date of the lease. In addition, the lease requires us upon certain events, such as a change in control, to purchase the building from the landlord. The purchase options were deemed to be fair value at the inception of the lease.

As of December 31, 2018, future estimated minimum lease payments under non-cancelable operating and financing leases were as follows (in thousands):


	Operating Leases		Financing Obligations
2019	$	4,755	$	2,893
2020	3,723		2,893
2021	3,640		2,893
2022	3,363		2,655
2023	3,029		1,471
Thereafter	10,693		24,868
Total minimum lease payments	$	29,203	37,673
Less: Amount representing interest			(19,243)
Present value of financing obligations			$	18,430

Government Grants

Since 2009, we have participated in a program with a local area community college, enlisted by the state of Iowa, that provides reimbursement of training dollars spent on employees hired in Iowa. The community college funds training through the sale of certificates for the amount of anticipated training expenses to be incurred and an estimate of the costs to administer the program. At each payroll date, the state allows us to direct a specified portion of employee state income tax withholdings for the qualified employees to the community college. The community college uses the funds to pay for the program and principal and interest on the certificates. In the event that the funds generated from withholding taxes are insufficient to pay the principal and interest on the certificates, we would be liable for any shortfall. We have concluded that the realization of amounts received under this program is contingent on continuing employment levels. Therefore, in accordance with ASC 450, the amounts received are recorded on the balance sheet as a liability until all contingencies have been resolved. During the years ended December 31, 2018, 2017 and 2016, the total benefit recorded on the statement of operations was $0.2 million, $1.6 million and $1.0 million, respectively.

Other Purchase Commitments

In November 2017, we entered into an agreement with a third party provider of cloud infrastructure services for a period of two years beginning December 1, 2017. As of December 31, 2018, we are committed to pay $2.7 million during the next 12 months.

Litigation

From time to time we may become involved in legal proceedings or be subject to claims arising in the ordinary course of our business. We evaluate the development of legal matters on a regular basis and accrue a liability when we believe a loss is probable and the amount can be reasonably estimated. Although the results of litigation and claims cannot be predicted with certainty, we currently believe that the final outcome of any currently pending legal proceedings to which we are a party will not have a material adverse effect on our business, operating results, financial condition or cash flows. Regardless of

the outcome, litigation can have an adverse impact on us because of defense and settlement costs, diversion of management resources and other factors.

Debt	12 Months Ended
Debt	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	Debt Other Long-Term Debt In August 2014, we entered into a $15.0 million credit facility with Silicon Valley Bank, which was subsequently amended. The credit facility can be used to fund working capital and general business requirements and matures in August 2020. The credit facility is secured by all of our assets, has first priority over our other debt obligations, and requires us to maintain certain financial covenants, including the maintenance of at least $5.0 million of cash on hand or unused borrowing capacity. The credit facility contains certain restrictive covenants that limit our ability to transfer or dispose of assets, merge with other companies or consummate certain changes of control, acquire other companies, pay dividends, incur additional indebtedness and liens, experience changes in management and enter into new businesses. The credit facility has a variable interest rate equal to the bank’s prime lending rate with interest payable monthly and the principal balance due at maturity. The credit facility’s interest rate was 5.5% at December 31, 2018. We recorded no interest expense for the years ended December 31, 2018, 2017 and 2016 related to such debt agreement. In November 2018, we issued a letter of credit for $0.5 million as a security deposit for new office space. The issuance of the letter of credit reduced the borrowing capacity under our line of credit to approximately $14.5 million. No other amounts were outstanding under the credit facility as of December 31, 2018 and 2017.

Stockholders' Equity (Deficit)	12 Months Ended
Stockholders' Equity (Deficit)	Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity (Deficit)	Stockholders’ Equity (Deficit)We have two classes of authorized common stock: Class A common stock and Class B common stock. The rights of the holders of our Class A common stock and our Class B common stock are identical, except with respect to voting and conversion. Each share of our Class A common stock is entitled to one vote per share and is not convertible into any other shares of our capital stock. Each share of our Class B common stock is entitled to ten votes per share and is convertible into one share of our Class A common stock at any time. Our Class B common stock also will automatically convert into shares of our Class A common stock upon certain transfers and other events.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

We grant stock-based incentive awards to attract, motivate and retain qualified employees, non-employee directors and consultants, and to align their financial interests with those of our stockholders. We utilize stock-based compensation in the form of restricted stock awards, restricted stock units, options to purchase Class A common stock and ESPP purchase rights. Prior to our corporate conversion in December 2014, awards were provided under the 2009 Unit Incentive Plan (the 2009 Plan). Immediately prior to our IPO, the 2009 Plan was amended to provide that no further awards will be issued thereunder, and our board of directors and stockholders adopted and approved our 2014 Equity Incentive Plan (the 2014 Plan and, together with the 2009 Plan, the Plans).

As of December 31, 2018, awards granted under the 2009 Plan consisted of stock options and awards granted under the 2014 Plan consisted of stock options, restricted stock awards and restricted stock units. There were no other grants of any other award types under the Plans.

In June 2016 and June 2018, stockholders approved amendments to the 2014 Plan that increased the number of shares available for grant by 3,900,000 and 3,000,000, respectively. As of December 31, 2018, 3,091,981 shares of Class A common stock were available for grant under the 2014 Plan.

Our Employee Stock Purchase Plan (“ESPP”) became effective on June 13, 2017. Under the ESPP, eligible employees are granted options to purchase shares of Class A common stock at the lower of 85% of the fair market value of the stock at the time of grant or 85% of the fair market value at the time of exercise. Options to purchase shares are granted twice yearly on or about July 15 and January 15 and are exercisable on or about the succeeding January 14 and July 14, respectively, of each year. As of December 31, 2018, 4,820,623 shares of Class A common stock were available for issuance under the ESPP. No participant may purchase more than $12,500 worth of Class A common stock in a six-month offering period.

Stock-Based Compensation Expense

Stock-based compensation expense was recorded in the following cost and expense categories consistent with the respective employee or service provider’s related cash compensation (in thousands):


	Year ended December 31,
	2018		2017		2016
Cost of revenue
Subscription and support	$	700	$	738	$	493
Professional services	619		465		411
Operating expenses
Research and development	5,842		2,224		2,365
Sales and marketing	5,416		2,983		2,075
General and administrative	18,264		13,066		8,903
Total	$	30,841	$	19,476	$	14,247

The fair value of each option grant and each share issued under the ESPP is estimated on the date of grant using the Black-Scholes option-pricing model. For stock options, expected volatility is based on the historical volatility of our Class A common stock and historical volatilities for publicly traded stock of comparable companies over the estimated expected life of the options. For the ESPP purchase rights, expected volatility is based on the historical volatility of our Class A common stock. The expected term represents the period of time the options and the ESPP purchase rights are expected to be outstanding. For stock options, the expected term is based on the “simplified method” as defined by SEC Staff Accounting

Bulletin No. 110 (Topic 14.D.2). We use the “simplified method” due to the lack of sufficient historical exercise data to provide a reasonable basis upon which to otherwise estimate the expected life of the options. The expected term for the ESPP purchase rights approximates the offering period. The risk-free interest rate is based on yields on U.S. Treasury STRIPS (Separate Trading of Registered Interest and Principal of Securities) with a maturity similar to the estimated expected term of the options and ESPP purchase rights.

The fair value of our stock options and ESPP purchase rights was estimated assuming no expected dividends and the following weighted-average assumptions:


	Year ended December 31,
	2018	2017	2016
Stock Options
Expected term (in years)	—	0.2 - 6.1	6.0 - 6.1
Risk-free interest rate	—	1.5% - 2.2%	1.2% - 2.1%
Expected volatility	—	23.7% - 43.8%	43.0% - 45.3%

ESPP
Expected term (in years)	0.5	0.5	—
Risk-free interest rate	1.8% - 2.4%	1.2%	—%
Expected volatility	22.2% - 36.4%	28.5%	—%

Stock Options

The following table summarizes the option activity under the Plans for the year ended December 31, 2018:


	Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Outstanding at December 31, 2017	8,145,777	$	13.33	7.0	$	65,913
Granted	—	—
Forfeited	(264,864)	17.22
Exercised	(1,480,738)	11.25
Outstanding at December 31, 2018	6,400,175	$	13.65	6.1	$	142,340

Exercisable at December 31, 2018	4,905,844	$	12.88	5.6	$	112,884

Options to purchase Class A common stock generally vest over a three- or four-year period and are generally granted for a term of ten years. The total intrinsic value of options exercised during the years ended December 31, 2018, 2017 and 2016 was $27.5 million, $9.8 million and $3.9 million, respectively.

The weighted-average grant-date fair value of options granted during the years ended December 31, 2017 and 2016 was $6.79 and $6.79, respectively. No options were granted during the year ended December 31, 2018. The total fair value of options vested during the years ended December 31, 2018, 2017 and 2016 was approximately $12.4 million, $10.2 million and $9.3 million, respectively. Total

unrecognized compensation expense of $8.3 million related to options will be recognized over a weighted-average period of 2.0 years.

Restricted Stock Awards

We have granted restricted stock awards to our executive officers that vest in three equal annual installments from the date of grant. The recipient of an award of restricted stock under the Plan may vote and receive dividends on the shares of restricted stock covered by the award. The fair value for restricted stock awards is calculated based on the stock price on the date of grant. The total fair value of restricted stock awards vested during the years ended December 31, 2018, 2017, and 2016 was approximately $2.2 million, $2.7 million, and $3.3 million respectively.

The following table summarizes the restricted stock award activity under the Plan for the year ended December 31, 2018:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2017	163,332	13.40
Granted	—	—
Forfeited	—	—
Vested	(163,332)	13.40
Unvested at December 31, 2018	—	—

Compensation expense associated with unvested restricted stock awards is recognized on a straight-line basis over the vesting period. At December 31, 2018, there was no unrecognized compensation expense related to restricted stock awards.

Restricted Stock Units

Restricted stock units granted to employees generally vest over a three- or four-year period in equal, annual installments or with three-year cliff vesting. Restricted stock units granted to non-employee members of our Board of Directors generally have one-year cliff vesting from the date of grant. The recipient of a restricted stock unit award under the Plan will have no rights as a stockholder until share certificates are issued by us, but, at the discretion of our Compensation Committee, has the right to receive a dividend equivalent payment in the form of additional restricted stock units. Additionally, until the shares are issued, they have no voting rights and may not be bought or sold. The fair value for restricted stock unit awards is calculated based on the stock price on the date of grant. The total fair value of restricted stock units vested during the years ended December 31, 2018 and 2017 was approximately $7.7 million and $3.6 million, respectively. No restricted stock units vested during the year ended December 31, 2016.

The following table summarizes the restricted stock unit activity under the Plan for the year ended December 31, 2018:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2017	574,072	$	14.51
Granted	2,295,322	24.84
Forfeited	(47,733)	22.85
Vested⁽¹⁾	(462,400)	16.73
Unvested at December 31, 2018	2,359,261	$	23.95

(1) During the year ended December 31, 2018 recipients of 417,163 shares had elected to defer settlement of the vested restricted stock units in accordance with our Nonqualified Deferred Compensation Plan resulting in total deferred units of 554,621 as of December 31, 2018.

Compensation expense associated with unvested restricted stock units is recognized on a straight-line basis over the vesting period. At December 31, 2018, there was approximately $41.6 million of total unrecognized compensation expense related to restricted stock units, which is expected to be recognized over a weighted-average period of 2.4 years.

Employee Stock Purchase Plan

During the year ended December 31, 2018, 179,377 shares of common stock were purchased under the ESPP at a weighted-average price of $17.93 per share, resulting in cash proceeds of $3.2 million.

Compensation expense associated with ESPP purchase rights is recognized on a straight-line basis over the vesting period. At December 31, 2018, there was approximately $52,000 of total unrecognized compensation expense related to the ESPP, which is expected to be recognized over a weighted-average period of 0.04 years.

Accumulated Other Comprehensive Income

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Accumulated Other Comprehensive Income

The following table summarizes the activity of accumulated other comprehensive income during the years ended December 31, 2018, 2017 and 2016 (in thousands):


	Accumulated translation adjustment		Accumulated unrealized holding gains (losses) on available-for-sale securities		Accumulated other comprehensive income
Balance at December 31, 2015	$	280	$	(39)	$	241
Other comprehensive income	18		32		50
Balance at December 31, 2016	298		(7)		291
Other comprehensive loss	(159)		(60)		(219)
Balance at December 31, 2017	139		(67)		72
Other comprehensive income	26		—		26
Balance at December 31, 2018	$	165	$	(67)	$	98

Segments	12 Months Ended
Segments	Dec. 31, 2018
Segment Reporting [Abstract]
Segments	Segments Our chief operating decision maker reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. There are no segment managers who are held accountable by the chief operating decision maker, or anyone else, for operations, operating results and planning for levels or components below the consolidated unit level. Accordingly, we determined we have one operating and reportable segment. During the years ended December 31, 2018, 2017 and 2016, 90.5%, 92.1% and 93.8% of our revenue, respectively, and substantially all of our long-lived assets were attributable to operations in the United States.

Revenue Recognition

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Disaggregation of Revenue

The following table presents our revenues disaggregated by industry (in thousands). Certain amounts have been reclassified to conform with current period presentation. These reclassifications have no impact on total revenue.


	For the year ended December 31, 2018
Information technology	$	31,063
Consumer discretionary	28,325
Industrials	28,023
Diversified financials	27,335
Banks	23,818
Healthcare	21,672
Energy	19,617
Other	64,491
Total revenues	$	244,344

The following table presents our revenues disaggregated by type of good or service (in thousands):


	For the year ended December 31, 2018
Subscription and support	$	200,392
XBRL professional services	30,562
Other services	13,390
Total revenues	$	244,344

Deferred Revenue

During the year ended December 31, 2018, we recognized $103.9 million of revenue that was included in the deferred revenue balance at the beginning of the period.

Transaction Price Allocated to the Remaining Performance Obligations

As of December 31, 2018, revenue of approximately $173.7 million is expected to be recognized from remaining performance obligations for subscription contracts. We expect to recognize approximately $148.5 million of these remaining performance obligations over the next 12 months, with the balance recognized thereafter.

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Taxes

Loss before income tax provision (benefit) consisted of the following (in thousands):


	For the year ended December 31,
	2018		2017		2016
United States	$	(50,268)	$	(44,246)	$	(43,952)
Foreign	444		(119)		(1)
Total	$	(49,824)	$	(44,365)	$	(43,953)

The provision (benefit) for income taxes consisted of the following (in thousands):


	For the year ended December 31,
	2018		2017		2016
Current
State	$	48	$	42	$	12
Foreign	203		19		44
Total Current	$	251	$	61	$	56

Deferred
Federal	$	(8)	$	—	$	(32)
Foreign	4		—		—
Total Deferred	$	(4)	$	—	$	(32)

Total	$	247	$	61	$	24

During the years ended December 31, 2018, 2017 and 2016, we recorded a federal income tax benefit of $8,000, $0, and $32,000, respectively. That benefit was primarily related to the allocation of tax expense (benefit) between continuing operations and other comprehensive income (loss) when applying the exception to the ASC 740 intraperiod tax allocation rule. Intraperiod tax allocation rules require us to allocate the provision for income taxes between continuing operations and other categories of earnings, such as other comprehensive income. In periods in which we have a year-to-date pre-tax loss from continuing operations and pre-tax income in other categories of earnings, such as other comprehensive income, we must allocate the tax provision to the other categories of earnings and then record a related tax benefit in continuing operations. This exception to the general rule applies even when a valuation allowance is in place at the beginning and end of the year.

The items accounting for the difference between income taxes computed at the federal statutory income tax rate and the provision for income taxes consisted of the following (in thousands):


	For the year ended December 31,
	2018			2017			2016
Federal statutory rate	21.0		%	35.0		%	35.0		%
Effect of:
Tax benefit at federal statutory rate	$	(10,463)		$	(15,528)		$	(15,384)
State taxes, net of federal benefit	(2,587)			(1,802)			(1,377)
Revaluation of deferred tax items due to tax rate change (federal and state)	—			22,880			—
Revaluation of deferred tax asset for current year net operating loss due to tax rate change	—			4,134			—
Permanent differences including section 162(m) limitations, stock compensation, gain on foreign restructuring, and meals & entertainment	2,113			5,141			1,292
Tax benefit of federal R&D credit	(3,289)			(2,366)			(1,781)
Recognition of excess tax benefits related to share-based payments	—			(3,606)			—
Valuation allowance	14,044			(8,586)			17,013
Other	429			(206)			261
Total income tax provision	$	247		$	61		$	24

The components of deferred tax assets and liabilities were as follows (in thousands):


	As of December 31,
	2018		2017
Deferred tax assets:
Property and equipment	$	18	$	15
Accruals and reserves	283		199
Deferred rent	1,601		931
Compensation and benefits	13,925		11,973
Deferred revenue	5,338		4,762
Net operating loss and credits	51,931		41,108
Other	701		167
Total deferred tax assets	73,797		59,155
Valuation allowance	(72,683)		(58,639)
Total deferred tax assets	1,114		516
Deferred tax liabilities:
Property and equipment	(529)		(440)
Other deferred tax liabilities	(587)		(76)
Deferred tax liabilities	(1,116)		(516)
Total	$	(2)	$	—

On December 22, 2017, the U.S. federal government enacted legislation commonly referred to as the “Tax Cuts and Jobs Act” (the “TCJA”). The TCJA made widespread changes to the Internal Revenue Code, including, among other items, a reduction in the federal corporate tax rate from 35% to 21%, effective January 1, 2018. Our financial statements for the current year reflect the effects of the TCJA based on current guidance.

As of December 31, 2018, we have completed the accounting for all the impacts of the TCJA. We continue to evaluate the impacts of the TCJA and will consider additional guidance from the U.S. Treasury Department, IRS or other standard-setting bodies. However, no additional adjustments were recorded by us during the measurement period in 2018 as permitted by SEC Staff Accounting Bulletin 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act.

Management assesses the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit use of the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred over the three-year period ended December 31, 2018. Such objective evidence limits the ability to consider other subjective evidence, such as our projections for future growth. On the basis of this evaluation, we recognized a full valuation allowance against our net US deferred tax asset at December 31, 2018, because we believe it is more likely than not that these benefits will not be realized.

As of December 31, 2018, we have federal and state net operating loss carryforwards of approximately $160.9 million and $126.2 million, respectively, available to reduce any future taxable income. The federal net operating loss carryforwards will expire in varying amounts beginning in 2034. As a result of the TCJA the federal and some state net operating losses incurred after 2017 will have an indefinite carryforward. The state net operating loss carryforwards will expire in varying amounts beginning in 2021. Additionally, we have total net operating loss carryforwards from international operations of $647,000 that do not expire. We also have approximately $9.3 million of federal and $1.8 million of state tax credit carryforwards as of December 31, 2018. The federal credits will expire in varying amounts between the years 2034 and 2038. The state credits expire beginning in 2021.

A reconciliation of the gross unrecognized tax benefits is as follows (in thousands):


	For the year ended December 31,
	2018		2017		2016
Unrecognized tax benefits-beginning of period	$	191	$	168	$	—
Additions for tax positions related to prior year	—		—		168
Reductions for tax positions related to prior year	—		—		—
Foreign currency adjustments	(9)		23		—
Additions for tax positions related to current year	—		—		—
Unrecognized tax benefits-end of period	$	182	$	191	$	168

We have analyzed our inventory of tax positions taken with respect to all applicable income tax issues for all open tax years. The gross unrecognized tax benefits, if recognized, would not materially affect the effective tax rate as of December 31, 2018, due to the availability of net operating losses.

We do not expect our gross unrecognized tax benefits to change significantly over the next 12 months. Our policy is to classify interest and penalties associated with uncertain tax positions, if any, as a component of our income tax provision. Interest and penalties were not significant during the years ended December 31, 2018, 2017 and 2016.

We are subject to taxation in the United States and various states and foreign jurisdictions. As of December 31, 2018, tax years for 2014 through 2017 are subject to examination by the tax authorities.

With few exceptions, as of December 31, 2018, we are no longer subject to U.S. federal, state, local or foreign examinations by tax authorities for years before 2014.

Net Loss Per Share

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Net Loss Per Share

Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential shares of common stock, including our outstanding stock options, stock related to unvested restricted stock awards, and common stock issuable pursuant to the ESPP to the extent dilutive.

The net loss per share is allocated based on the contractual participation rights of the Class A and Class B common shares as if the loss for the year has been distributed. As the liquidation and dividend rights are identical, the net loss is allocated on a proportionate basis.

We consider unvested restricted stock awards granted under the 2014 Equity Incentive Plan to be participating securities because holders of such shares have non-forfeitable dividend rights in the event of our declaration of a dividend for common shares. In future periods to the extent we are profitable, we will subtract earnings allocated to these participating securities from net income to determine net income attributable to common stockholders.

A reconciliation of the denominator used in the calculation of basic and diluted loss per share is as follows (in thousands, except share and per share data):


	Year ended
	December 31, 2018						December 31, 2017						December 31, 2016
	Class A		Class B		Class A		Class B		Class A		Class B
Numerator
Net loss	$	(38,733)	$	(11,338)	$	(33,016)	$	(11,410)	$	(31,644)	$	(12,333)

Denominator
Weighted-average common shares outstanding - basic and diluted	33,758,623		9,881,785		30,929,899		10,688,939		29,265,605		11,405,528
Basic and diluted net loss per share	$	(1.15)	$	(1.15)	$	(1.07)	$	(1.07)	$	(1.08)	$	(1.08)

The anti-dilutive securities excluded from the weighted-average shares used to calculate the diluted net loss per common share were as follows:


	As of December 31,
	2018	2017	2016
Shares subject to outstanding common stock options	6,400,175	8,145,777	7,532,455
Shares subject to unvested restricted stock awards	—	163,332	353,335
Shares subject to unvested restricted stock units	2,359,261	574,072	381,952
Shares issuable pursuant to the ESPP	105,583	85,509	—

Unaudited Quarterly Results of Operations

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Unaudited Quarterly Results of Operations

The following tables set forth selected unaudited quarterly consolidated statement of operations data for each of the quarters indicated as well as the percentage of total revenue for each line item shown. The unaudited information should be read in conjunction with our financial statements and related notes included elsewhere in this report. We believe that the following unaudited information reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period.


	Three months ended
	Dec 31, 2018		Sep 30, 2018		Jun 30, 2018		Mar 31, 2018		Dec 31, 2017		Sep 30, 2017		Jun 30, 2017		Mar 31, 2017
	(in thousands)
Revenue
Subscription and support	$	53,779	$	51,306	$	48,837	$	46,470	$	45,549	$	43,214	$	40,980	$	39,540
Professional services	10,656		9,567		10,293		13,436		8,957		8,854		8,411		12,364
Total revenue	64,435		60,873		59,130		59,906		54,506		52,068		49,391		51,904
Cost of revenue
Subscription and support	8,637		8,139		8,637		8,802		8,779		8,472		7,758		7,637
Professional services	8,757		7,520		7,659		7,709		7,310		7,180		6,528		6,581
Total cost of revenue	17,394		15,659		16,296		16,511		16,089		15,652		14,286		14,218
Gross profit	47,041		45,214		42,834		43,395		38,417		36,416		35,105		37,686
Operating expenses
Research and development	20,773		19,984		20,718		20,127		18,870		17,527		16,239		15,536
Sales and marketing	23,011		24,068		22,252		21,006		21,949		23,712		19,787		18,713
General and administrative ⁽¹⁾⁽²⁾	11,047		11,864		21,654		11,768		12,271		8,959		8,943		9,421
Total operating expenses	54,831		55,916		64,624		52,901		53,090		50,198		44,969		43,670
Loss from operations	(7,790)		(10,702)		(21,790)		(9,506)		(14,673)		(13,782)		(9,864)		(5,984)
Interest expense	(480)		(448)		(449)		(450)		(451)		(464)		(475)		(455)
Other income, net	753		203		492		343		797		198		176		612
Loss before provision (benefit) for income taxes	(7,517)		(10,947)		(21,747)		(9,613)		(14,327)		(14,048)		(10,163)		(5,827)
Provision (benefit) for income taxes	204		17		21		5		(6)		25		33		9
Net loss	$	(7,721)	$	(10,964)	$	(21,768)	$	(9,618)	$	(14,321)	$	(14,073)	$	(10,196)	$	(5,836)
Net loss per common share:
Basic and diluted	$	(0.17)	$	(0.25)	$	(0.50)	$	(0.22)	$	(0.34)	$	(0.34)	$	(0.25)	$	(0.14)
Weighted-average common shares outstanding - basic and diluted	44,472,672		43,973,428		43,234,655		42,858,756		42,108,764		41,815,139		41,429,691		41,108,611

(1) During the fourth quarter of 2017, we recorded an additional $1.9 million to general and administrative expense due to certain severance arrangements.

(2) During the second quarter of 2018, we recorded an additional $5.9 million and $3.6 million of cash-based and equity-based compensation, respectively, to general and administrative expense pursuant to a separation agreement with our former CEO.

Organization and Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles and include the accounts of Workiva Inc. and its wholly owned subsidiaries.

Principles of Consolidation

All intercompany accounts and transactions have been eliminated in consolidation.

Reclassifications

Additionally, certain prior year amounts have been reclassified for consistency with the current year presentation. The reclassification of the prior period amounts were not material to the previously reported consolidated financial statements.

Foreign Currency

Use of Estimates

Cash and Cash Equivalents

Marketable Securities

Fair Value of Financial Instruments

Concentration of Credit Risk

Financial instruments that potentially subject us to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. We place our cash and cash equivalents with high credit-quality financial institutions. Such deposits may be in excess of federally insured limits. To date, we have not experienced any losses on our cash and cash equivalents. We perform periodic evaluations of the relative credit standing of the financial institutions.Our accounts receivable are derived primarily from customers located in North America. We perform ongoing credit evaluations of our customers’ financial condition and require no collateral from our customers. We maintain an allowance for doubtful accounts receivable based upon the expected collectability of accounts receivable balances.

Deferred Commissions

Property and Equipment, net

Revenue Recognition

We determine revenue recognition through the following steps:

•Identification of the contract, or contracts, with a customer

•Identification of the performance obligations in the contract

•Determination of the transaction price

•Allocation of the transaction price to the performance obligations in the contract

•Recognition of revenue when, or as, we satisfy a performance obligation

We report revenue net of sales and other taxes collected from customers to be remitted to government authorities.

Subscription and Support Revenue

Professional Services Revenue and Customer Options

Contracts with Multiple Performance Obligations

Deferred Revenue, Customer Deposits and Cost of Revenue

Deferred Revenue

Customer Deposits

Cost of Revenue

Selling and Marketing Expenses

Advertising Costs

Advertising costs are charged to sales and marketing expense as incurred.

Research and Development Expenses

General and Administrative Expenses

Leases

Government Grants

Government grants received are recorded as a liability on the balance sheets until all contingencies are resolved and the grant is determined to be realized.

Intangible Assets

Impairment of Long-Lived Assets

Stock-based Compensation

Income Taxes

adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

Accounts Receivable and Allowance for Doubtful Accounts

Recently Adopted Accounting Pronouncements and New Accounting Pronouncements Not Yet Adopted

The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of ASU 2014-09 were as follows (in thousands):


	As of December 31, 2017		Adjustments Due to ASU 2014-09		As of January 1, 2018
Assets
Accounts receivable, net	$	28,800	$	16,900	$	45,700
Deferred commissions	2,376		650		3,026
Deferred commissions, non-current	—		4,655		4,655

Liabilities
Accrued expenses and other current liabilities	20,429		6,956		27,385
Deferred revenue	104,684		6,625		111,309
Deferred revenue, non-current	22,709		243		22,952

Equity
Accumulated deficit	$	(265,337)	$	8,381	$	(256,956)


	As of December 31, 2018
	As Reported	Balances Without Adoption of ASC 606	Effect of Change
Assets
Accounts receivable, net	65,107	37,528	27,579
Deferred commissions	8,178	4,593	3,585
Deferred commissions, non-current	10,569	—	10,569

Liabilities
Accrued expenses and other current liabilities	36,353	28,958	7,395
Deferred revenue	148,545	134,793	13,752
Deferred revenue, non-current	25,171	20,853	4,318

Equity
Accumulated deficit	(307,027)	(323,295)	16,268


	Year ended December 31, 2018
	As Reported		Balances Without Adoption of ASC 606		Effect of Change
Revenues
Subscription and support	$	200,392	$	199,575	$	817
Professional services	43,952		45,707		(1,755)

Operating expenses
Sales and marketing	90,337		99,162		(8,825)

Net loss	$	(50,071)	$	(57,958)	$	7,887

Net loss per common share
Basic and diluted	$	(1.15)	$	(1.33)	$	0.18

The adoption of ASC 606 had no impact on our total cash flows from operations.

New Accounting Pronouncements Not Yet Adopted

Organization and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of New Accounting Pronouncements and Changes in Accounting Principles

The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of ASU 2014-09 were as follows (in thousands):


	As of December 31, 2017		Adjustments Due to ASU 2014-09		As of January 1, 2018
Assets
Accounts receivable, net	$	28,800	$	16,900	$	45,700
Deferred commissions	2,376		650		3,026
Deferred commissions, non-current	—		4,655		4,655

Liabilities
Accrued expenses and other current liabilities	20,429		6,956		27,385
Deferred revenue	104,684		6,625		111,309
Deferred revenue, non-current	22,709		243		22,952

Equity
Accumulated deficit	$	(265,337)	$	8,381	$	(256,956)


	As of December 31, 2018
	As Reported	Balances Without Adoption of ASC 606	Effect of Change
Assets
Accounts receivable, net	65,107	37,528	27,579
Deferred commissions	8,178	4,593	3,585
Deferred commissions, non-current	10,569	—	10,569

Liabilities
Accrued expenses and other current liabilities	36,353	28,958	7,395
Deferred revenue	148,545	134,793	13,752
Deferred revenue, non-current	25,171	20,853	4,318

Equity
Accumulated deficit	(307,027)	(323,295)	16,268


	Year ended December 31, 2018
	As Reported		Balances Without Adoption of ASC 606		Effect of Change
Revenues
Subscription and support	$	200,392	$	199,575	$	817
Professional services	43,952		45,707		(1,755)

Operating expenses
Sales and marketing	90,337		99,162		(8,825)

Net loss	$	(50,071)	$	(57,958)	$	7,887

Net loss per common share
Basic and diluted	$	(1.15)	$	(1.33)	$	0.18

Cash Equivalents and Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-sale Securities

At December 31, 2018, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
Money market funds	$	52,068	$	—	$	—	$	52,068
Commercial paper	7,448		—		—		7,448
U.S. treasury debt securities	2,494		—		(1)		2,493
U.S. corporate debt securities	10,890		—		(67)		10,823
	$	72,900	$	—	$	(68)	$	72,832
Included in cash and cash equivalents	$	52,068	$	—	$	—	$	52,068
Included in marketable securities	$	20,832	$	—	$	(68)	$	20,764

At December 31, 2017, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
Money market funds	$	49,452	$	—	$	—	$	49,452
U.S. treasury debt securities	3,083		—		(8)		3,075
U.S. corporate debt securities	13,350		—		(61)		13,289
	$	65,885	$	—	$	(69)	$	65,816
Included in cash and cash equivalents	$	49,452	$	—	$	—	$	49,452
Included in marketable securities	$	16,433	$	—	$	(69)	$	16,364

Schedule of Cash and Cash Equivalents

At December 31, 2018, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
Money market funds	$	52,068	$	—	$	—	$	52,068
Commercial paper	7,448		—		—		7,448
U.S. treasury debt securities	2,494		—		(1)		2,493
U.S. corporate debt securities	10,890		—		(67)		10,823
	$	72,900	$	—	$	(68)	$	72,832
Included in cash and cash equivalents	$	52,068	$	—	$	—	$	52,068
Included in marketable securities	$	20,832	$	—	$	(68)	$	20,764

At December 31, 2017, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
Money market funds	$	49,452	$	—	$	—	$	49,452
U.S. treasury debt securities	3,083		—		(8)		3,075
U.S. corporate debt securities	13,350		—		(61)		13,289
	$	65,885	$	—	$	(69)	$	65,816
Included in cash and cash equivalents	$	49,452	$	—	$	—	$	49,452
Included in marketable securities	$	16,433	$	—	$	(69)	$	16,364

Schedule of Available-for-sale Securities, Continuous Unrealized Loss Position


	As of December 31, 2018
	Less than 12 months						12 months or greater
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. treasury debt securities	$	—	$	—	$	998	$	(1)
U.S. corporate debt securities	3,481		(5)		7,342		(62)
Total	$	3,481	$	(5)	$	8,340	$	(63)

Supplemental Consolidated Balance Sheet and Statement of Operations Information (Tables)

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Property, Plant and Equipment

Property and equipment, net as of December 31, 2018 and 2017 consisted of (in thousands):


	As of December 31,
	2018		2017
Buildings	$	36,608	$	36,608
Computers, equipment and software	6,602		6,277
Furniture and fixtures	8,839		8,428
Vehicles	97		97
Leasehold improvements	7,678		4,669
Construction in process	15		—
	59,839		56,079
Less: accumulated depreciation and amortization	(18,371)		(15,635)
	$	41,468	$	40,444

Schedule of Capital Leased Assets

The following assets included in property and equipment, net were acquired under capital and financing leases (see Note 6) (in thousands):


	As of December 31,
	2018		2017
Buildings	$	36,608	$	36,608
Computers and equipment	—		666
	36,608		37,274
Less: accumulated amortization	(6,237)		(5,891)
	$	30,371	$	31,383

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities as of December 31, 2018 and 2017 consisted of (in thousands):


	As of December 31,
	2018		2017
Accrued vacation	$	6,906	$	6,087
Accrued commissions	7,265		3,297
Accrued bonuses	5,643		4,419
Estimated health insurance claims	1,100		1,090
ESPP employee contributions	2,156		1,419
Customer deposits	7,395		—
Accrued other liabilities	5,888		4,117
	$	36,353	$	20,429

Schedule of Other Income and (Expense), net

Other income, net for the years ended December 31, 2018, 2017 and 2016 consisted of (in thousands):


	For the year ended December 31,
	2018		2017		2016
Interest income	$	1,278	$	586	$	286
Income from training reimbursement program	—		1,578		1,141
Gains (losses) on foreign currency transactions	289		(372)		67
Other	224		(9)		6
	$	1,791	$	1,783	$	1,500

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Assets Measured on Recurring Basis

The following table presents information about our assets that are measured at fair value on a recurring basis using the above input categories (in thousands):


	Fair Value Measurements as of December 31, 2018										Fair Value Measurements as of December 31, 2017
Description	Total		Level 1		Level 2		Total		Level 1		Level 2
Money market funds	$	52,068	$	52,068	$	—	$	49,452	$	49,452	$	—
Commercial paper	7,448		—		7,448		—		—		—
U.S. treasury debt securities	2,493		—		2,493		3,075		—		3,075
U.S. corporate debt securities	10,823		—		10,823		13,289		—		13,289
	$	72,832	$	52,068	$	20,764	$	65,816	$	49,452	$	16,364

Included in cash and cash equivalents	$	52,068					$	49,452
Included in marketable securities	$	20,764					$	16,364

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Summary of Minimum Lease Payments

As of December 31, 2018, future estimated minimum lease payments under non-cancelable operating and financing leases were as follows (in thousands):


	Operating Leases		Financing Obligations
2019	$	4,755	$	2,893
2020	3,723		2,893
2021	3,640		2,893
2022	3,363		2,655
2023	3,029		1,471
Thereafter	10,693		24,868
Total minimum lease payments	$	29,203	37,673
Less: Amount representing interest			(19,243)
Present value of financing obligations			$	18,430

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Stock-based Compensation Expense

Stock-based compensation expense was recorded in the following cost and expense categories consistent with the respective employee or service provider’s related cash compensation (in thousands):


	Year ended December 31,
	2018		2017		2016
Cost of revenue
Subscription and support	$	700	$	738	$	493
Professional services	619		465		411
Operating expenses
Research and development	5,842		2,224		2,365
Sales and marketing	5,416		2,983		2,075
General and administrative	18,264		13,066		8,903
Total	$	30,841	$	19,476	$	14,247

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The fair value of our stock options and ESPP purchase rights was estimated assuming no expected dividends and the following weighted-average assumptions:


	Year ended December 31,
	2018	2017	2016
Stock Options
Expected term (in years)	—	0.2 - 6.1	6.0 - 6.1
Risk-free interest rate	—	1.5% - 2.2%	1.2% - 2.1%
Expected volatility	—	23.7% - 43.8%	43.0% - 45.3%

ESPP
Expected term (in years)	0.5	0.5	—
Risk-free interest rate	1.8% - 2.4%	1.2%	—%
Expected volatility	22.2% - 36.4%	28.5%	—%

Schedule of Share-based Payment Award, ESPP, Valuation Assumptions

The fair value of our stock options and ESPP purchase rights was estimated assuming no expected dividends and the following weighted-average assumptions:


	Year ended December 31,
	2018	2017	2016
Stock Options
Expected term (in years)	—	0.2 - 6.1	6.0 - 6.1
Risk-free interest rate	—	1.5% - 2.2%	1.2% - 2.1%
Expected volatility	—	23.7% - 43.8%	43.0% - 45.3%

ESPP
Expected term (in years)	0.5	0.5	—
Risk-free interest rate	1.8% - 2.4%	1.2%	—%
Expected volatility	22.2% - 36.4%	28.5%	—%

Schedule of Stock-Option Activity

The following table summarizes the option activity under the Plans for the year ended December 31, 2018:


	Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Outstanding at December 31, 2017	8,145,777	$	13.33	7.0	$	65,913
Granted	—	—
Forfeited	(264,864)	17.22
Exercised	(1,480,738)	11.25
Outstanding at December 31, 2018	6,400,175	$	13.65	6.1	$	142,340

Exercisable at December 31, 2018	4,905,844	$	12.88	5.6	$	112,884

Summary of Restricted Stock Awards

The following table summarizes the restricted stock award activity under the Plan for the year ended December 31, 2018:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2017	163,332	13.40
Granted	—	—
Forfeited	—	—
Vested	(163,332)	13.40
Unvested at December 31, 2018	—	—

Summary of Restricted Stock Units

The following table summarizes the restricted stock unit activity under the Plan for the year ended December 31, 2018:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2017	574,072	$	14.51
Granted	2,295,322	24.84
Forfeited	(47,733)	22.85
Vested⁽¹⁾	(462,400)	16.73
Unvested at December 31, 2018	2,359,261	$	23.95

Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income

The following table summarizes the activity of accumulated other comprehensive income during the years ended December 31, 2018, 2017 and 2016 (in thousands):


	Accumulated translation adjustment		Accumulated unrealized holding gains (losses) on available-for-sale securities		Accumulated other comprehensive income
Balance at December 31, 2015	$	280	$	(39)	$	241
Other comprehensive income	18		32		50
Balance at December 31, 2016	298		(7)		291
Other comprehensive loss	(159)		(60)		(219)
Balance at December 31, 2017	139		(67)		72
Other comprehensive income	26		—		26
Balance at December 31, 2018	$	165	$	(67)	$	98

Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue


	For the year ended December 31, 2018
Information technology	$	31,063
Consumer discretionary	28,325
Industrials	28,023
Diversified financials	27,335
Banks	23,818
Healthcare	21,672
Energy	19,617
Other	64,491
Total revenues	$	244,344

The following table presents our revenues disaggregated by type of good or service (in thousands):


	For the year ended December 31, 2018
Subscription and support	$	200,392
XBRL professional services	30,562
Other services	13,390
Total revenues	$	244,344

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

Loss before income tax provision (benefit) consisted of the following (in thousands):


	For the year ended December 31,
	2018		2017		2016
United States	$	(50,268)	$	(44,246)	$	(43,952)
Foreign	444		(119)		(1)
Total	$	(49,824)	$	(44,365)	$	(43,953)

Schedule of Components of Income Tax Expense (Benefit)

The provision (benefit) for income taxes consisted of the following (in thousands):


	For the year ended December 31,
	2018		2017		2016
Current
State	$	48	$	42	$	12
Foreign	203		19		44
Total Current	$	251	$	61	$	56

Deferred
Federal	$	(8)	$	—	$	(32)
Foreign	4		—		—
Total Deferred	$	(4)	$	—	$	(32)

Total	$	247	$	61	$	24

Schedule of Effective Income Tax Rate Reconciliation

The items accounting for the difference between income taxes computed at the federal statutory income tax rate and the provision for income taxes consisted of the following (in thousands):


	For the year ended December 31,
	2018			2017			2016
Federal statutory rate	21.0		%	35.0		%	35.0		%
Effect of:
Tax benefit at federal statutory rate	$	(10,463)		$	(15,528)		$	(15,384)
State taxes, net of federal benefit	(2,587)			(1,802)			(1,377)
Revaluation of deferred tax items due to tax rate change (federal and state)	—			22,880			—
Revaluation of deferred tax asset for current year net operating loss due to tax rate change	—			4,134			—
Permanent differences including section 162(m) limitations, stock compensation, gain on foreign restructuring, and meals & entertainment	2,113			5,141			1,292
Tax benefit of federal R&D credit	(3,289)			(2,366)			(1,781)
Recognition of excess tax benefits related to share-based payments	—			(3,606)			—
Valuation allowance	14,044			(8,586)			17,013
Other	429			(206)			261
Total income tax provision	$	247		$	61		$	24

Schedule of Deferred Tax Assets and Liabilities

The components of deferred tax assets and liabilities were as follows (in thousands):


	As of December 31,
	2018		2017
Deferred tax assets:
Property and equipment	$	18	$	15
Accruals and reserves	283		199
Deferred rent	1,601		931
Compensation and benefits	13,925		11,973
Deferred revenue	5,338		4,762
Net operating loss and credits	51,931		41,108
Other	701		167
Total deferred tax assets	73,797		59,155
Valuation allowance	(72,683)		(58,639)
Total deferred tax assets	1,114		516
Deferred tax liabilities:
Property and equipment	(529)		(440)
Other deferred tax liabilities	(587)		(76)
Deferred tax liabilities	(1,116)		(516)
Total	$	(2)	$	—

Schedule of Unrecognized Tax Benefits

A reconciliation of the gross unrecognized tax benefits is as follows (in thousands):


	For the year ended December 31,
	2018		2017		2016
Unrecognized tax benefits-beginning of period	$	191	$	168	$	—
Additions for tax positions related to prior year	—		—		168
Reductions for tax positions related to prior year	—		—		—
Foreign currency adjustments	(9)		23		—
Additions for tax positions related to current year	—		—		—
Unrecognized tax benefits-end of period	$	182	$	191	$	168

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

A reconciliation of the denominator used in the calculation of basic and diluted loss per share is as follows (in thousands, except share and per share data):


	Year ended
	December 31, 2018						December 31, 2017						December 31, 2016
	Class A		Class B		Class A		Class B		Class A		Class B
Numerator
Net loss	$	(38,733)	$	(11,338)	$	(33,016)	$	(11,410)	$	(31,644)	$	(12,333)

Denominator
Weighted-average common shares outstanding - basic and diluted	33,758,623		9,881,785		30,929,899		10,688,939		29,265,605		11,405,528
Basic and diluted net loss per share	$	(1.15)	$	(1.15)	$	(1.07)	$	(1.07)	$	(1.08)	$	(1.08)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The anti-dilutive securities excluded from the weighted-average shares used to calculate the diluted net loss per common share were as follows:


	As of December 31,
	2018	2017	2016
Shares subject to outstanding common stock options	6,400,175	8,145,777	7,532,455
Shares subject to unvested restricted stock awards	—	163,332	353,335
Shares subject to unvested restricted stock units	2,359,261	574,072	381,952
Shares issuable pursuant to the ESPP	105,583	85,509	—

Unaudited Quarterly Results of Operations (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information


	Three months ended
	Dec 31, 2018		Sep 30, 2018		Jun 30, 2018		Mar 31, 2018		Dec 31, 2017		Sep 30, 2017		Jun 30, 2017		Mar 31, 2017
	(in thousands)
Revenue
Subscription and support	$	53,779	$	51,306	$	48,837	$	46,470	$	45,549	$	43,214	$	40,980	$	39,540
Professional services	10,656		9,567		10,293		13,436		8,957		8,854		8,411		12,364
Total revenue	64,435		60,873		59,130		59,906		54,506		52,068		49,391		51,904
Cost of revenue
Subscription and support	8,637		8,139		8,637		8,802		8,779		8,472		7,758		7,637
Professional services	8,757		7,520		7,659		7,709		7,310		7,180		6,528		6,581
Total cost of revenue	17,394		15,659		16,296		16,511		16,089		15,652		14,286		14,218
Gross profit	47,041		45,214		42,834		43,395		38,417		36,416		35,105		37,686
Operating expenses
Research and development	20,773		19,984		20,718		20,127		18,870		17,527		16,239		15,536
Sales and marketing	23,011		24,068		22,252		21,006		21,949		23,712		19,787		18,713
General and administrative ⁽¹⁾⁽²⁾	11,047		11,864		21,654		11,768		12,271		8,959		8,943		9,421
Total operating expenses	54,831		55,916		64,624		52,901		53,090		50,198		44,969		43,670
Loss from operations	(7,790)		(10,702)		(21,790)		(9,506)		(14,673)		(13,782)		(9,864)		(5,984)
Interest expense	(480)		(448)		(449)		(450)		(451)		(464)		(475)		(455)
Other income, net	753		203		492		343		797		198		176		612
Loss before provision (benefit) for income taxes	(7,517)		(10,947)		(21,747)		(9,613)		(14,327)		(14,048)		(10,163)		(5,827)
Provision (benefit) for income taxes	204		17		21		5		(6)		25		33		9
Net loss	$	(7,721)	$	(10,964)	$	(21,768)	$	(9,618)	$	(14,321)	$	(14,073)	$	(10,196)	$	(5,836)
Net loss per common share:
Basic and diluted	$	(0.17)	$	(0.25)	$	(0.50)	$	(0.22)	$	(0.34)	$	(0.34)	$	(0.25)	$	(0.14)
Weighted-average common shares outstanding - basic and diluted	44,472,672		43,973,428		43,234,655		42,858,756		42,108,764		41,815,139		41,429,691		41,108,611

(1) During the fourth quarter of 2017, we recorded an additional $1.9 million to general and administrative expense due to certain severance arrangements.

Organization and Significant Accounting Policies - Foreign Currency (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Gains (losses) on foreign currency transactions	$ 289	$ (372)	$ 67

Organization and Significant Accounting Policies - Property and Equipment, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Depreciation	$ 3.4	$ 3.4	$ 3.7
Amortization of assets under capital lease	$ 1.3	$ 1.6	$ 2.1
Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years

Organization and Significant Accounting Policies - Deferred Commissions, Revenue Recognition and Advertising Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Sales commissions amortization period	3 years
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advertising expense	$ 2.9	$ 2.7	$ 2.7
Subscription and support
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue recognition, customer contract period, min	3 months
Revenue recognition, customer contract period, max	36 months

Organization and Significant Accounting Policies - Intangible Assets (Details) - Patents - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years
Finite-lived intangible assets, accumulated amortization	$ 320	$ 218
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	113
2020	113
2021	113
2022	113
2023	96
Thereafter	$ 217

Organization and Significant Accounting Policies - Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized cost, amortization period under new and prior guidance		12 months
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized cost, amortization period under new and prior guidance	3 years
Pro Forma \| Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liability	$ 16.0
Operating lease asset	$ 16.0

Organization and Significant Accounting Policies - Adoption of New Accounting Standards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
ASSETS
Accounts receivable, net	$ 65,107				$ 28,800				$ 65,107	$ 28,800		$ 45,700
Deferred commissions	8,178				2,376				8,178	2,376		3,026
Deferred commissions, non-current	10,569				0				10,569	0		4,655
Liabilities
Accrued expenses and other current liabilities	36,353				20,429				36,353	20,429		27,385
Deferred revenue	148,545				104,684				148,545	104,684		111,309
Deferred revenue, non-current	25,171				22,709				25,171	22,709		22,952
Accumulated deficit	(307,027)				(265,337)				(307,027)	(265,337)		(256,956)
Revenue
Total revenue	64,435	$ 60,873	$ 59,130	$ 59,906	54,506	$ 52,068	$ 49,391	$ 51,904	244,344	207,869	$ 178,646
Operating expenses
Sales and marketing	23,011	24,068	22,252	21,006	21,949	23,712	19,787	18,713	90,337	84,161	80,466
Net loss	$ (7,721)	$ (10,964)	$ (21,768)	$ (9,618)	$ (14,321)	$ (14,073)	$ (10,196)	$ (5,836)	$ (50,071)	$ (44,426)	$ (43,977)
Net loss per common share:
Basic and diluted (in dollars per share)	$ (0.17)	$ (0.25)	$ (0.50)	$ (0.22)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (1.15)	$ (1.07)	$ (1.08)
Balances Without Adoption of ASC 606
ASSETS
Accounts receivable, net	$ 37,528				$ 28,800				$ 37,528	$ 28,800
Deferred commissions	4,593				2,376				4,593	2,376
Deferred commissions, non-current	0				0				0	0
Liabilities
Accrued expenses and other current liabilities	28,958				20,429				28,958	20,429
Deferred revenue	134,793				104,684				134,793	104,684
Deferred revenue, non-current	20,853				22,709				20,853	22,709
Accumulated deficit	(323,295)				(265,337)				(323,295)	(265,337)
Operating expenses
Sales and marketing									99,162
Net loss									$ (57,958)
Net loss per common share:
Basic and diluted (in dollars per share)									$ (1.33)
Accounting Standards Update 2014-09 \| Effect of Change
ASSETS
Accounts receivable, net	27,579								$ 27,579			16,900
Deferred commissions	3,585								3,585			650
Deferred commissions, non-current	10,569								10,569			4,655
Liabilities
Accrued expenses and other current liabilities	7,395								7,395			6,956
Deferred revenue	13,752								13,752			6,625
Deferred revenue, non-current	4,318								4,318			243
Accumulated deficit	16,268								16,268			$ 8,381
Operating expenses
Sales and marketing									(8,825)
Net loss									$ 7,887
Net loss per common share:
Basic and diluted (in dollars per share)									$ 0.18
Subscription and support
Revenue
Total revenue	53,779	$ 51,306	$ 48,837	$ 46,470	45,549	$ 43,214	$ 40,980	$ 39,540	$ 200,392	169,283	$ 143,120
Subscription and support \| Balances Without Adoption of ASC 606
Revenue
Total revenue									199,575
Subscription and support \| Accounting Standards Update 2014-09 \| Effect of Change
Revenue
Total revenue									817
Professional services
Revenue
Total revenue	$ 10,656	$ 9,567	$ 10,293	$ 13,436	$ 8,957	$ 8,854	$ 8,411	$ 12,364	43,952	$ 38,586	$ 35,526
Professional services \| Balances Without Adoption of ASC 606
Revenue
Total revenue									45,707
Professional services \| Accounting Standards Update 2014-09 \| Effect of Change
Revenue
Total revenue									$ (1,755)

Cash Equivalents and Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 77,584	$ 60,333
Debt Securities, Available-for-sale [Line Items]
Unrealized Gains	0	0
Unrealized Losses	(68)	(69)
Cash and cash equivalents and available-for-sale securities, amortized cost	72,900	65,885
Cash and cash equivalents and available-for-sale securities	72,832	65,816
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7,448
Unrealized Gains	0
Unrealized Losses	0
Aggregate Fair Value	7,448
U.S. treasury debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,494	3,083
Unrealized Gains	0	0
Unrealized Losses	(1)	(8)
Aggregate Fair Value	2,493	3,075
U.S. corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,890	13,350
Unrealized Gains	0	0
Unrealized Losses	(67)	(61)
Aggregate Fair Value	10,823	13,289
Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	52,068	49,452
Cash and cash equivalents, aggregate fair value	52,068	49,452
Cash and cash equivalents \| Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	52,068	49,452
Cash and cash equivalents, aggregate fair value	52,068	49,452
Marketable securities \| U.S. corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	20,832	16,433
Unrealized Gains	0	0
Unrealized Losses	(68)	(69)
Aggregate Fair Value	$ 20,764	$ 16,364

Cash Equivalents and Marketable Securities - Continuous Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Fair Value
Less than 12 months	$ 3,481
12 months or greater	8,340
Unrealized Loss
Less than 12 months	(5)
12 months or greater	(63)
U.S. treasury debt securities
Fair Value
Less than 12 months	0
12 months or greater	998
Unrealized Loss
Less than 12 months	0
12 months or greater	(1)
U.S. corporate debt securities
Fair Value
Less than 12 months	3,481
12 months or greater	7,342
Unrealized Loss
Less than 12 months	(5)
12 months or greater	$ (62)

Supplemental Consolidated Balance Sheet and Statement of Operations Information - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 59,839	$ 56,079
Less: accumulated depreciation and amortization	(18,371)	(15,635)
Property and equipment	41,468	40,444
Capital Leases, Balance Sheet, Assets by Major Class, Net [Abstract]
Financing leased assets, gross	36,608	37,274
Less: accumulated amortization	(6,237)	(5,891)
Financing leased assets	30,371	31,383
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	36,608	36,608
Capital Leases, Balance Sheet, Assets by Major Class, Net [Abstract]
Financing leased assets, gross	36,608	36,608
Computers, equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,602	6,277
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	8,839	8,428
Vehicles
Property, Plant and Equipment [Line Items]
Property and equipment, gross	97	97
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,678	4,669
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15	0
Computers and equipment
Capital Leases, Balance Sheet, Assets by Major Class, Net [Abstract]
Financing leased assets, gross	$ 0	$ 666

Supplemental Consolidated Balance Sheet and Statement of Operations Information - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Accrued Liabilities and Other Liabilities [Abstract]
Accrued vacation	$ 6,906		$ 6,087
Accrued commissions	7,265		3,297
Accrued bonuses	5,643		4,419
Estimated health insurance claims	1,100		1,090
ESPP employee contributions	2,156		1,419
Customer deposits	7,395		0
Accrued other liabilities	5,888		4,117
Accrued expenses and other current liabilities	$ 36,353	$ 27,385	$ 20,429

Supplemental Consolidated Balance Sheet and Statement of Operations Information - Other Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Nonoperating Income (Expense) [Abstract]
Interest income									$ 1,278	$ 586	$ 286
Income from training reimbursement program									0	1,578	1,141
Gains (losses) on foreign currency transactions									289	(372)	67
Other									224	(9)	6
Other income, net	$ 753	$ 203	$ 492	$ 343	$ 797	$ 198	$ 176	$ 612	$ 1,791	$ 1,783	$ 1,500

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 7,448
U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	2,493	$ 3,075
U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	10,823	13,289
U.S. corporate debt securities \| Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	20,764	16,364
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents - money market funds	52,068	49,452
Money market funds \| Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents - money market funds	52,068	49,452
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	72,832	65,816
Recurring \| Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents - money market funds	52,068	49,452
Recurring \| Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	20,764	16,364
Recurring \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	7,448	0
Recurring \| U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	2,493	3,075
Recurring \| U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	10,823	13,289
Recurring \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents - money market funds	52,068	49,452
Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	52,068	49,452
Recurring \| Level 1 \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Recurring \| Level 1 \| U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Recurring \| Level 1 \| U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Recurring \| Level 1 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents - money market funds	52,068	49,452
Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	20,764	16,364
Recurring \| Level 2 \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	7,448	0
Recurring \| Level 2 \| U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	2,493	3,075
Recurring \| Level 2 \| U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	10,823	13,289
Recurring \| Level 2 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents - money market funds	$ 0	$ 0

Deferred Costs (Details) $ in Thousands	12 Months Ended
Deferred Costs (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Revenue from Contract with Customer [Abstract]
Deferred costs	$ 18,700
Amortization expense for deferred costs	10,100
Impairment loss	$ 0

Commitments and Contingencies - Lease Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 5.6	$ 4.7	$ 3.9

Commitments and Contingencies - Build to Suit (Details) - Ames, Iowa Building Lease $ in Millions	1 Months Ended	12 Months Ended
	Jun. 20, 2013 USD ($)	Dec. 31, 2018 USD ($) phase	Dec. 31, 2014 USD ($)
Property, Plant and Equipment [Line Items]
Number of phases \| phase		2
Lessor committed fundings, phase 1		$ 11.8
Lessor committed fundings, phase 2		$ 11.1
Reclassification to financing obligation	$ 11.8		$ 11.1
Purchase option period		3 years
Buildings
Property, Plant and Equipment [Line Items]
Assets placed into service	$ 17.1		$ 19.9

Commitments and Contingencies - Minimum Lease Payments Under Operating and Financing Leases (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Operating Leases
2019	$ 4,755
2020	3,723
2021	3,640
2022	3,363
2023	3,029
Thereafter	10,693
Total minimum lease payments	29,203
Financing Lease Obligation
Financing Obligations
2019	2,893
2020	2,893
2021	2,893
2022	2,655
2023	1,471
Thereafter	24,868
Total minimum lease payments	37,673
Less: Amount representing interest	(19,243)
Present value of financing obligations	$ 18,430

Commitments and Contingencies - Government Grants (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gain Contingencies [Line Items]
Income from training reimbursement program	$ 0	$ 1,578	$ 1,141
Other income, net
Gain Contingencies [Line Items]
Income from training reimbursement program	$ 200	$ 1,600	$ 1,000

Commitments and Contingencies - Other Purchase Commitments (Details) - Cloud infrastructure services - USD ($) $ in Millions	1 Months Ended
	Nov. 30, 2017	Dec. 31, 2018
Unrecorded Unconditional Purchase Obligation [Line Items]
Other purchase commitments, term	2 years
Other purchase commitments, due within twelve months		$ 2.7

Debt (Details) - Line of Credit - Silicon Valley Bank - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2018	Aug. 31, 2014
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 15,000,000.0
Debt covenant, Minimum cash on hand or unused borrowing capacity	$ 5,000,000.0
Interest rate at period end	5.50%
Interest expense	$ 0	$ 0	$ 0
Issued letter of credit				$ 500,000
Remaining borrowing capacity				$ 14,500,000
Line of credit	$ 0	$ 0

Stockholders' Equity (Deficit) (Details)	12 Months Ended
Stockholders' Equity (Deficit) (Details)	Dec. 31, 2018 class vote
Equity [Abstract]
Number of classes of common stock \| class	2
Class A Common Stock
Class of Stock [Line Items]
Common stock, number of votes per share	1
Class B Common Stock
Class of Stock [Line Items]
Common stock, number of votes per share	10
Common stock, conversion rate	1

Stock-Based Compensation - Narrative (Details) - USD ($)		1 Months Ended		12 Months Ended
	Jun. 13, 2017	Jun. 30, 2018	Jun. 30, 2016	Dec. 31, 2018
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock purchase offering period				6 months
Employee Stock Purchase Plan \| Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant				4,820,623
Purchase price of common stock, percentage of fair market value	85.00%
Maximum stock purchase value per employee	$ 12,500
2014 Equity Incentive Plan \| Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares available for grant		3,000,000	3,900,000
Number of shares available for grant				3,091,981

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 30,841	$ 19,476	$ 14,247
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	5,842	2,224	2,365
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	5,416	2,983	2,075
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	18,264	13,066	8,903
Subscription and support \| Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	700	738	493
Professional services \| Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 619	$ 465	$ 411

Stock-Based Compensation - Assumptions (Details)	12 Months Ended
Stock-Based Compensation - Assumptions (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee stock options
Weighted-Average Assumptions
Expected term (in years)	0 years
Risk-free interest rate, min (as percent)		1.50%	1.20%
Risk-free interest rate, max (as percent)		2.20%	2.10%
Risk-free interest rate (as percent)	0.00%
Expected volatility, min (as percent)		23.70%	43.00%
Expected volatility, max (as percent)		43.80%	45.30%
Expected volatility (as percent)	0.00%
Employee stock options \| Minimum
Weighted-Average Assumptions
Expected term (in years)		2 months 12 days	6 years
Employee stock options \| Maximum
Weighted-Average Assumptions
Expected term (in years)		6 years 1 month 6 days	6 years 1 month 6 days
Employee Stock Purchase Plan
Weighted-Average Assumptions
Expected term (in years)	6 months	6 months	0 years
Risk-free interest rate, min (as percent)	1.80%
Risk-free interest rate, max (as percent)	2.40%
Risk-free interest rate (as percent)		1.20%	0.00%
Expected volatility, min (as percent)	22.20%
Expected volatility, max (as percent)	36.40%
Expected volatility (as percent)		28.50%	0.00%

Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Options (in shares):
Outstanding beginning of the period (in shares)	8,145,777
Granted (in shares)	0
Forfeited (in shares)	(264,864)
Exercised (in shares)	(1,480,738)
Outstanding end of the period (in shares)	6,400,175	8,145,777
Exercisable at end of the period (in shares)	4,905,844
Weighted-Average Exercise Price (in dollars per share):
Outstanding beginning of the period (in dollars per share)	$ 13.33
Granted (in dollars per share)	0
Forfeited (in dollars per share)	17.22
Exercised (in dollars per share)	11.25
Outstanding end of the period (in dollars per share)	13.65	$ 13.33
Exercisable at the end of the period (in dollars per share)	$ 12.88
Outstanding, weighted-average remaining contractual term (years)	6 years 1 month 6 days	7 years
Exercisable, weighted-average remaining contractual term (years)	5 years 7 months 6 days
Outstanding, aggregate intrinsic value	$ 142,340	$ 65,913
Exercisable, aggregate intrinsic value	112,884
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options exercised intrinsic value	27,500	$ 9,800	$ 3,900
Options grants in period, weighted average grant date fair value (in dollars per share)		$ 6.79	$ 6.79
Options vested in period fair value	12,400	$ 10,200	$ 9,300
Options unrecognized compensation expense	$ 8,300
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options unrecognized compensation expense, period for recognition (years)	2 years
Class A Common Stock \| Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Expiration period (years)	10 years
Minimum \| Class A Common Stock \| Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Award vesting period (years)	3 years
Maximum \| Class A Common Stock \| Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Award vesting period (years)	4 years

Stock-Based Compensation - Restricted Stock Awards (Details) - Restricted stock awards - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period, fair value	$ 2,200,000	$ 2,700,000	$ 3,300,000
Number of Shares (in shares)
Unvested at beginning of period (in shares)	163,332
Granted (in shares)	0
Forfeited (in shares)	0
Vested (in shares)	(163,332)
Unvested at end of period (in shares)	0	163,332
Weighted- Average Grant Date Fair Value (in dollars per share)
Unvested at beginning of period (in dollars per share)	$ 13.40
Granted (in dollars per share)	0
Forfeited (in dollars per share)	0
Vested (in dollars per share)	13.40
Unvested at end of period (in dollars per share)	$ 0	$ 13.40
Unrecognized compensation expense	$ 0
Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years

Stock-Based Compensation - Restricted Stock Units (Details) - Restricted stock units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period, fair value	$ 7.7	$ 3.6
Number of Shares (in shares)
Unvested at beginning of period (in shares)	574,072
Granted (in shares)	2,295,322
Forfeited (in shares)	(47,733)
Vested (in shares)	(462,400)		0
Unvested at end of period (in shares)	2,359,261	574,072
Weighted- Average Grant Date Fair Value (in dollars per share)
Unvested at beginning of period (in dollars per share)	$ 14.51
Granted (in dollars per share)	24.84
Forfeited (in dollars per share)	22.85
Vested (in dollars per share)	16.73
Unvested at end of period (in dollars per share)	$ 23.95	$ 14.51
Unrecognized compensation expense	$ 41.6
Unrecognized compensation expense, period for recognition (years)	2 years 4 months 24 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	4 years
Cliff-vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Cliff-vesting \| Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	1 year
Deferred vesting
Number of Shares (in shares)
Vested (in shares)	(417,163)
Weighted- Average Grant Date Fair Value (in dollars per share)
Accumulated number of shares recipients have elected to defer settlement (in shares)	554,621

Stock-Based Compensation - Employee Stock Purchase Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from shares issued in connection with employee stock purchase plan	$ 3,216	$ 0	$ 0
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 52
Unrecognized compensation expense, period for recognition (years)	14 days
Class A Common Stock \| Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued during period	179,377
Shares issued during period, weighted average price per share (in dollars per share)	$ 17.93
Proceeds from shares issued in connection with employee stock purchase plan	$ 3,200

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of the period	$ (16,934)	$ (3,125)	$ 25,719
Other comprehensive income (loss)	26	(219)	50
End of the period	(9,740)	(16,934)	(3,125)
Accumulated translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of the period	139	298	280
Other comprehensive income (loss)	26	(159)	18
End of the period	165	139	298
Accumulated unrealized holding gains (losses) on available-for-sale securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of the period	(67)	(7)	(39)
Other comprehensive income (loss)	0	(60)	32
End of the period	(67)	(67)	(7)
Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of the period	72	291	241
Other comprehensive income (loss)	26	(219)	50
End of the period	$ 98	$ 72	$ 291

Segments (Details) - segment	12 Months Ended
Segments (Details) - segment	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1
Revenue from contract with customer \| Geographic concentration risk \| United States
Concentration Risk [Line Items]
Concentration risk percentage	90.50%	92.10%	93.80%

Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Total revenue	$ 64,435	$ 60,873	$ 59,130	$ 59,906	$ 54,506	$ 52,068	$ 49,391	$ 51,904	$ 244,344	$ 207,869	$ 178,646
Subscription and support
Disaggregation of Revenue [Line Items]
Total revenue	$ 53,779	$ 51,306	$ 48,837	$ 46,470	$ 45,549	$ 43,214	$ 40,980	$ 39,540	200,392	$ 169,283	$ 143,120
XBRL professional services
Disaggregation of Revenue [Line Items]
Total revenue									30,562
Other services
Disaggregation of Revenue [Line Items]
Total revenue									13,390
Information technology
Disaggregation of Revenue [Line Items]
Total revenue									31,063
Consumer discretionary
Disaggregation of Revenue [Line Items]
Total revenue									28,325
Industrials
Disaggregation of Revenue [Line Items]
Total revenue									28,023
Diversified financials
Disaggregation of Revenue [Line Items]
Total revenue									27,335
Banks
Disaggregation of Revenue [Line Items]
Total revenue									23,818
Healthcare
Disaggregation of Revenue [Line Items]
Total revenue									21,672
Energy
Disaggregation of Revenue [Line Items]
Total revenue									19,617
Other
Disaggregation of Revenue [Line Items]
Total revenue									$ 64,491

Revenue Recognition - Deferred Revenue and Transaction Price Allocated to the Remaining Performance Obligations (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Revenue from Contract with Customer [Abstract]
Deferred revenue recognized	$ 103.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized	$ 148.5
Expected period of recognition	12 months

Income Taxes - Income Before Income Tax, Domestic and Foreign (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
United States									$ (50,268)	$ (44,246)	$ (43,952)
Foreign									444	(119)	(1)
Loss before provision for income taxes	$ (7,517)	$ (10,947)	$ (21,747)	$ (9,613)	$ (14,327)	$ (14,048)	$ (10,163)	$ (5,827)	$ (49,824)	$ (44,365)	$ (43,953)

Income Taxes - Components of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
State									$ 48	$ 42	$ 12
Foreign									203	19	44
Total Current									251	61	56
Deferred
Federal									(8)	0	(32)
Foreign									4	0	0
Total Deferred									(4)	0	(32)
Total income tax provision	$ 204	$ 17	$ 21	$ 5	$ (6)	$ 25	$ 33	$ 9	$ 247	$ 61	$ 24

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal income tax benefit	$ 8	$ 0	$ 32

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal statutory rate									21.00%	35.00%	35.00%
Tax benefit at federal statutory rate									$ (10,463)	$ (15,528)	$ (15,384)
State taxes, net of federal benefit									(2,587)	(1,802)	(1,377)
Revaluation of deferred tax items due to tax rate change (federal and state)									0	22,880	0
Revaluation of deferred tax asset for current year net operating loss due to tax rate change									0	4,134	0
Permanent differences including section 162(m) limitations, stock compensation, gain on foreign restructuring, and meals & entertainment									2,113	5,141	1,292
Tax benefit of federal R&D credit									(3,289)	(2,366)	(1,781)
Recognition of excess tax benefits related to share-based payments									0	(3,606)	0
Valuation allowance									14,044	(8,586)	17,013
Other									429	(206)	261
Total income tax provision	$ 204	$ 17	$ 21	$ 5	$ (6)	$ 25	$ 33	$ 9	$ 247	$ 61	$ 24

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Property and equipment	$ 18	$ 15
Accruals and reserves	283	199
Deferred rent	1,601	931
Compensation and benefits	13,925	11,973
Deferred revenue	5,338	4,762
Net operating loss and credits	51,931	41,108
Other	701	167
Total deferred tax assets	73,797	59,155
Valuation allowance	(72,683)	(58,639)
Total deferred tax assets	1,114	516
Deferred tax liabilities:
Property and equipment	(529)	(440)
Other deferred tax liabilities	(587)	(76)
Deferred tax liabilities	(1,116)	(516)
Total	$ (2)	$ 0

Income Taxes - Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 160,900
State Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	126,200
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 647

Income Taxes - Tax Credit Carryforwards (Details) $ in Millions	Dec. 31, 2018 USD ($)
Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 9.3
State Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 1.8

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits-beginning of period	$ 191	$ 168	$ 0
Additions for tax positions related to prior year	0	0	168
Reductions for tax positions related to prior year	0	0	0
Foreign currency adjustments	(9)
Foreign currency adjustments		23	0
Additions for tax positions related to current year	0	0	0
Unrecognized tax benefits-end of period	182	191	168
Interest and penalties	$ 0	$ 0	$ 0

Net Loss Per Share - Earnings Per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Denominator
Weighted-average common shares outstanding - basic and diluted (in shares)	44,472,672	43,973,428	43,234,655	42,858,756	42,108,764	41,815,139	41,429,691	41,108,611	43,640,408	41,618,838	40,671,133
Basic and diluted net loss per share (in dollars per share)	$ (0.17)	$ (0.25)	$ (0.50)	$ (0.22)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (1.15)	$ (1.07)	$ (1.08)
Class A Common Stock
Numerator
Net loss									$ (38,733)	$ (33,016)	$ (31,644)
Denominator
Weighted-average common shares outstanding - basic and diluted (in shares)									33,758,623	30,929,899	29,265,605
Basic and diluted net loss per share (in dollars per share)									$ (1.15)	$ (1.07)	$ (1.08)
Class B Common Stock
Numerator
Net loss									$ (11,338)	$ (11,410)	$ (12,333)
Denominator
Weighted-average common shares outstanding - basic and diluted (in shares)									9,881,785	10,688,939	11,405,528
Basic and diluted net loss per share (in dollars per share)									$ (1.15)	$ (1.07)	$ (1.08)

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares subject to outstanding common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	6,400,175	8,145,777	7,532,455
Shares subject to unvested restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	163,332	353,335
Shares subject to unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,359,261	574,072	381,952
Shares issuable pursuant to the ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	105,583	85,509	0

Unaudited Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Total revenue	$ 64,435	$ 60,873	$ 59,130	$ 59,906	$ 54,506	$ 52,068	$ 49,391	$ 51,904	$ 244,344	$ 207,869	$ 178,646
Cost of revenue
Total cost of revenue	17,394	15,659	16,296	16,511	16,089	15,652	14,286	14,218	65,860	60,245	51,625
Gross profit	47,041	45,214	42,834	43,395	38,417	36,416	35,105	37,686	178,484	147,624	127,021
Operating expenses
Research and development	20,773	19,984	20,718	20,127	18,870	17,527	16,239	15,536	81,602	68,172	57,438
Sales and marketing	23,011	24,068	22,252	21,006	21,949	23,712	19,787	18,713	90,337	84,161	80,466
General and administrative	11,047	11,864	21,654	11,768	12,271	8,959	8,943	9,421	56,333	39,594	32,695
Total operating expenses	54,831	55,916	64,624	52,901	53,090	50,198	44,969	43,670	228,272	191,927	170,599
Loss from operations	(7,790)	(10,702)	(21,790)	(9,506)	(14,673)	(13,782)	(9,864)	(5,984)	(49,788)	(44,303)	(43,578)
Interest expense	(480)	(448)	(449)	(450)	(451)	(464)	(475)	(455)	(1,827)	(1,845)	(1,875)
Other income, net	753	203	492	343	797	198	176	612	1,791	1,783	1,500
Loss before provision for income taxes	(7,517)	(10,947)	(21,747)	(9,613)	(14,327)	(14,048)	(10,163)	(5,827)	(49,824)	(44,365)	(43,953)
Provision (benefit) for income taxes	204	17	21	5	(6)	25	33	9	247	61	24
Net loss	$ (7,721)	$ (10,964)	$ (21,768)	$ (9,618)	$ (14,321)	$ (14,073)	$ (10,196)	$ (5,836)	$ (50,071)	$ (44,426)	$ (43,977)
Basic and diluted (in dollars per share)	$ (0.17)	$ (0.25)	$ (0.50)	$ (0.22)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (1.15)	$ (1.07)	$ (1.08)
Weighted-average common shares outstanding - basic and diluted (in shares)	44,472,672	43,973,428	43,234,655	42,858,756	42,108,764	41,815,139	41,429,691	41,108,611	43,640,408	41,618,838	40,671,133
Subscription and support
Revenue
Total revenue	$ 53,779	$ 51,306	$ 48,837	$ 46,470	$ 45,549	$ 43,214	$ 40,980	$ 39,540	$ 200,392	$ 169,283	$ 143,120
Cost of revenue
Total cost of revenue	8,637	8,139	8,637	8,802	8,779	8,472	7,758	7,637	34,215	32,646	27,895
Professional services
Revenue
Total revenue	10,656	9,567	10,293	13,436	8,957	8,854	8,411	12,364	43,952	38,586	35,526
Cost of revenue
Total cost of revenue	$ 8,757	$ 7,520	7,659	$ 7,709	7,310	$ 7,180	$ 6,528	$ 6,581	$ 31,645	$ 27,599	$ 23,730
General and administrative
Operating expenses
Compensation expense					$ 1,900
Chief Executive Officer \| General and administrative
Operating expenses
Compensation expense			3,600
Severance costs			$ 5,900

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 8,381,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 8,381,000