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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2017	Feb. 20, 2018	Jun. 30, 2017
Entity Information [Line Items]
Entity Registrant Name	WORKIVA INC
Entity Central Index Key	0001445305
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Amendment Flag	false
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 555.5
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		32,364,250
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		10,203,371

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 60,333	$ 51,281
Marketable securities	16,364	11,435
Accounts receivable, net of allowance for doubtful accounts of $388 and $900 at December 31, 2017 and December 31, 2016, respectively	28,800	22,535
Deferred commissions	2,376	1,864
Other receivables	975	1,545
Prepaid expenses	6,444	9,382
Total current assets	115,292	98,042
Property and equipment, net	40,444	42,590
Intangible assets, net	1,118	1,012
Other assets	861	1,499
Total assets	157,715	143,143
Current liabilities
Accounts payable	3,060	849
Accrued expenses and other current liabilities	20,212	20,695
Deferred revenue	104,684	76,016
Deferred government grant obligation	217	1,022
Current portion of capital lease and financing obligations	1,168	1,285
Current portion of long-term debt	0	20
Total current liabilities	129,341	99,887
Deferred revenue	22,709	21,485
Deferred government grant obligation	278	1,000
Other long-term liabilities	3,896	4,100
Capital lease and financing obligations	18,425	19,743
Long-term debt	0	53
Total liabilities	174,649	146,268
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	248,289	217,454
Accumulated deficit	(265,337)	(220,911)
Accumulated other comprehensive income	72	291
Total stockholders’ deficit	(16,934)	(3,125)
Total liabilities and stockholders’ deficit	157,715	143,143
Class A Common Stock
Stockholders’ deficit
Common stock	32	30
Class B Common Stock
Stockholders’ deficit
Common stock	$ 10	$ 11

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts	$ 388	$ 900
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, share authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	32,165,407	30,369,199
Common stock, shares outstanding	32,165,407	30,369,199
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, share authorized	500,000,000	500,000,000
Common stock, shares issued	10,203,371	10,891,888
Common stock, shares outstanding	10,203,371	10,891,888

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue
Subscription and support	$ 45,549	$ 43,214	$ 40,980	$ 39,540	$ 38,329	$ 36,237	$ 34,969	$ 33,585	$ 169,283	$ 143,120	$ 116,288
Professional services	8,957	8,854	8,411	12,364	8,045	8,473	8,042	10,966	38,586	35,526	28,984
Total revenue	54,506	52,068	49,391	51,904	46,374	44,710	43,011	44,551	207,869	178,646	145,272
Cost of revenue
Subscription and support	8,779	8,472	7,758	7,637	7,244	6,694	7,039	6,918	32,646	27,895	22,559
Professional services	7,310	7,180	6,528	6,581	5,964	6,040	5,538	6,188	27,599	23,730	17,645
Total cost of revenue	16,089	15,652	14,286	14,218	13,208	12,734	12,577	13,106	60,245	51,625	40,204
Gross profit	38,417	36,416	35,105	37,686	33,166	31,976	30,434	31,445	147,624	127,021	105,068
Operating expenses
Research and development	18,870	17,527	16,239	15,536	14,533	14,342	14,047	14,516	68,172	57,438	50,466
Sales and marketing	21,949	23,712	19,787	18,713	18,196	22,354	19,828	20,088	84,161	80,466	69,569
General and administrative	12,271	8,959	8,943	9,421	7,845	8,015	7,882	8,953	39,594	32,695	28,716
Total operating expenses	53,090	50,198	44,969	43,670	40,574	44,711	41,757	43,557	191,927	170,599	148,751
Loss from operations	(14,673)	(13,782)	(9,864)	(5,984)	(7,408)	(12,735)	(11,323)	(12,112)	(44,303)	(43,578)	(43,683)
Interest expense	(451)	(464)	(475)	(455)	(455)	(462)	(468)	(490)	(1,845)	(1,875)	(2,025)
Other income, net	797	198	176	612	348	298	278	576	1,783	1,500	2,302
Loss before provision (benefit) for income taxes	(14,327)	(14,048)	(10,163)	(5,827)	(7,515)	(12,899)	(11,513)	(12,026)	(44,365)	(43,953)	(43,406)
Provision (benefit) for income taxes	(6)	25	33	9	1	(8)	12	19	61	24	(7)
Net loss	$ (14,321)	$ (14,073)	$ (10,196)	$ (5,836)	$ (7,516)	$ (12,891)	$ (11,525)	$ (12,045)	$ (44,426)	$ (43,977)	$ (43,399)
Net loss per common share:
Basic and diluted (in dollars per share)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (0.18)	$ (0.32)	$ (0.28)	$ (0.30)	$ (1.07)	$ (1.08)	$ (1.09)
Weighted average common shares outstanding - basic and diluted (in shares)	42,108,764	41,815,139	41,429,691	41,108,611	40,872,772	40,762,960	40,593,908	40,451,668	41,618,838	40,671,133	39,852,624

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (44,426)	$ (43,977)	$ (43,399)
Other comprehensive (loss) income, net of tax
Foreign currency translation adjustment, net of income tax (expense) of ($2), ($13) and ($101) for the years ended December 31, 2017, 2016 and 2015, respectively	(159)	18	133
Unrealized gain (loss) on available-for-sale securities, net of income tax (expense) benefit of $2, ($19), and $25 for the years ended December 31, 2017, 2016 and 2015, respectively	(60)	32	(39)
Other comprehensive (loss) income, net of tax	(219)	50	94
Comprehensive loss	$ (44,645)	$ (43,927)	$ (43,305)

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, tax (expense)	$ (2)	$ (13)	$ (101)
Unrealized (loss) gain on available-for-sale securities, tax (expense) benefit	$ 2	$ (19)	$ 25

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
Shares outstanding, beginning of the period (in shares) at Dec. 31, 2014		39,641,000
Beginning of the period at Dec. 31, 2014	$ 55,819	$ 39	$ 189,168	$ 147	$ (133,535)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	11,000		11,000
Grant of restricted stock award (in shares)		600,000
Issuance of common stock upon exercise of stock options (in shares)		707,000
Issuance of common stock upon exercise of stock options	2,244	$ 2	2,242
Net loss	(43,399)				(43,399)
Distribution to members	(35)		(35)
Cost of offering	(4)		(4)
Other comprehensive income (loss)	94			94
Shares outstanding, end of the period (in shares) at Dec. 31, 2015		40,948,000
End 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		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 (loss)	50			50
Shares outstanding, 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
Grant of restricted stock award (in shares)		30,000
Issuance of common stock upon exercise of stock options (in shares)	1,158,820	1,159,000
Issuance of common stock upon exercise of stock options	$ 12,485	$ 1	12,484
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 (loss)	(219)			(219)
Shares outstanding, 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)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net loss	$ (44,426)	$ (43,977)	$ (43,399)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	3,546	3,820	4,410
Stock-based compensation expense	19,476	14,247	11,000
(Recovery of) provision for doubtful accounts	(517)	185	449
Realized gain on sale of available-for-sale securities, net	0	(6)	(13)
Amortization of premiums and discounts on marketable securities, net	101	147	77
Recognition of deferred government grant obligation	(1,578)	(1,141)	(2,383)
Deferred income tax	0	(32)	(76)
Changes in assets and liabilities:
Accounts receivable	(5,546)	(7,101)	(5,080)
Deferred commissions	(498)	(497)	(520)
Other receivables	577	(732)	(523)
Prepaid expenses	2,952	(5,513)	(734)
Other assets	618	(654)	81
Accounts payable	2,206	(3,930)	2,331
Deferred revenue	29,367	34,211	7,297
Accrued expenses and other liabilities	(758)	604	5,390
Change in restricted cash	0	0	101
Net cash provided by (used in) operating activities	5,520	(10,369)	(21,592)
Cash flows from investing activities
Purchase of property and equipment	(1,188)	(1,901)	(1,843)
Purchase of marketable securities	(14,369)	(1,301)	(24,069)
Maturities of marketable securities	9,281	0	0
Sale of marketable securities	0	7,197	6,521
Purchase of intangible assets	(197)	(190)	(386)
Net cash (used in) provided by investing activities	(6,473)	3,805	(19,777)
Cash flows from financing activities
Payment of equity issuance costs	0	0	(1,346)
Proceeds from option exercises	12,485	1,597	2,244
Taxes paid related to net share settlements of stock-based compensation awards	(1,125)	(761)	0
Changes in restricted cash	0	0	300
Repayment of other long-term debt	(73)	(18)	(84)
Principal payments on capital lease and financing obligations	(1,435)	(1,863)	(2,282)
Distributions to members	0	0	(381)
Proceeds from government grants	51	183	548
Deferred financing costs	(81)	(33)	0
Repayment of government grant	0	0	(101)
Net cash provided by (used in) financing activities	9,822	(895)	(1,102)
Effect of foreign exchange rates on cash	183	(10)	90
Net increase (decrease) in cash and cash equivalents	9,052	(7,469)	(42,381)
Cash and cash equivalents at beginning of year	51,281	58,750	101,131
Cash and cash equivalents at end of year	60,333	51,281	58,750
Supplemental cash flow disclosure
Cash paid for interest	1,627	1,835	2,048
Cash paid for income taxes, net of refunds	42	47	64
Supplemental disclosure of noncash investing and financing activities
Fixed assets acquired through capital lease arrangements	0	0	527
Government grant recorded against property and equipment, net	0	0	908
Allowance for tenant improvements	0	481	698
Purchases of property and equipment, accrued but not paid	$ 0	$ 0	$ 354

Organization and Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Significant Accounting Policies	Organization and Significant Accounting Policies Organization Workiva Inc., a Delaware corporation, and its wholly-owned subsidiaries (the "Company" or "we" or "us") created Wdesk, an intuitive cloud platform that modernizes how people work within thousands of organizations. Wdesk is built on a data management engine, offering controlled collaboration, data connections, granular permissions and a full audit trail. We offer Wdesk solutions for a wide range of use cases in the following markets: finance and accounting, audit and internal controls, risk and compliance and performance and management reporting. Our operational headquarters are located in Ames, Iowa, with additional offices located in the United States, Europe, 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. 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’ equity. 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 $(372,000), $67,000 and $(293,000) of transaction (losses) gains during the years ended December 31, 2017, 2016 and 2015, 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 determination of the relative selling prices of our services, health insurance claims incurred but not yet reported, collectability of accounts receivable, valuation of available-for-sale marketable securities, useful lives of 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 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 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. 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, 2017 or 2016. 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, $3.7 million and $4.4 million for the years ended December 31, 2017, 2016 and 2015, respectively, and included $1.6 million, $2.1 million and $2.4 million of amortization of assets recorded under capital leases during the years ended December 31, 2017, 2016 and 2015, respectively. Revenue Recognition We generate revenue through the sale of subscriptions to our cloud-based software and the delivery of professional services. Our customer contracts typically range in length from three to 36 months. Our arrangements do not contain general rights of return. Our subscription contracts do not provide customers with the right to take possession of the software supporting the applications and, as a result, are accounted for as service contracts. We commence revenue recognition for subscriptions to our cloud applications and professional services when all of the following criteria are met: There is persuasive evidence of an arrangement; The service has been or is being provided to the customer; Collection of the fees is reasonably assured; and The amount of fees to be paid by the customer is fixed or determinable. Collectability is assessed based on a number of factors, including past transaction history with the customer and the creditworthiness of the customer. Collateral is not requested from the customer. If it is determined that the collection of a fee is not probable, the revenue is deferred until collection becomes probable, which is generally upon the receipt of cash. Revenue is reported net of sales and other taxes collected from customers to be remitted to government authorities. Subscription and Support Revenue We recognize the aggregate minimum subscription and support fees ratably on a straight-line basis over the subscription term, provided that an enforceable contract has been signed by both parties, access to our SaaS solutions has been granted to the customer, the fee for the subscription and support is fixed or determinable, and collection is reasonably assured. Professional Services Revenue We recognize revenue for our professional services contracts when the services are performed. Multiple Deliverable Arrangements For arrangements with multiple deliverables, we evaluate whether the individual deliverables qualify as separate units of accounting. In order to treat deliverables in a multiple deliverable arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. For deliverables that have standalone value upon delivery, we account for each deliverable separately and recognize revenue for the respective deliverables as they are delivered. Subscription contracts have standalone value as we sell the subscriptions separately. In determining whether professional services can be accounted for separately from subscription services, we consider the availability of the professional services from other vendors, the nature of our professional services and whether we sell our applications to new customers without professional services. In the years ended December 31, 2017, 2016 and 2015, we determined that we had established standalone value for our professional services. This determination was made due primarily to the ability of the customer to complete these tasks without assistance and the sale of services separate from the initial subscription order. Because we established standalone value for our professional services in the years ended December 31, 2017, 2016 and 2015, such service arrangements are being accounted for separately from subscription services. When multiple deliverables included in an arrangement are separable into different units of accounting, the arrangement consideration is allocated to the identified separate units of accounting based on their relative selling price. Multiple deliverable arrangements accounting guidance provides a hierarchy to use when determining the relative selling price for each unit of accounting. Vendor-specific objective evidence (VSOE) of selling price, based on the price at which the item is regularly sold by the vendor on a standalone basis, should be used if it exists. If VSOE of selling price is not available, third-party evidence (TPE) of selling price is used to establish the selling price if it exists. VSOE and TPE do not currently exist for any of our deliverables. Accordingly, for arrangements with multiple deliverables that can be separated into different units of accounting, we allocate the arrangement fee to the separate units of accounting based on our best estimate of selling price. The amount of arrangement fee allocated is limited by contingent revenue, if any. We determine our best estimate of selling price for our deliverables based on our overall pricing objectives, taking into consideration market conditions and entity-specific factors. We evaluate our best estimate of selling price by reviewing historical data related to sales of our deliverables, including comparing the percentages of our contract prices to our list prices. We also may consider several other data points in our evaluation, including the size of our arrangements, length of term, the cloud applications sold, customer demographics and the numbers and types of users within our arrangements. Deferred Revenue We typically invoice our customers for subscription 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 services starting in future periods are excluded from accounts receivable and deferred revenue. Invoiced amounts are reflected as accounts receivable once we have initiated services with an offset to deferred revenue or revenue depending on whether the revenue recognition criteria have been met. Deferred revenue also includes certain deferred professional service fees that are recognized upon completion of the service. 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. 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 and Deferred Commissions 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. We amortize sales commissions that are directly attributable to a contract over the lesser of 12 months or the non-cancelable term of the customer contract based on the terms of our commission arrangements. Advertising costs are charged to sales and marketing expense as incurred. Advertising expense totaled $2.7 million, $2.7 million and $2.8 million for the years ended December 31, 2017, 2016 and 2015, 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. Leasehold improvements are capitalized at cost and amortized over the shorter of their useful life or the term of the lease. Government Grants Government grants received are recorded as a liability on the balance sheet 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, 2017 and 2016 was approximately $218,000 and $127,000, respectively. Future amortization expense for legally approved patents is estimated at $94,000 per year through 2022 and approximately $211,000 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. 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 makes 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 we become subject to GILTI. 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 statement of operations. Accrued interest and penalties are included on the related tax liability line in the consolidated balance sheet. 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 March 2016, the FASB issued ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. Under this ASU, entities are permitted to make an accounting policy election either to estimate forfeitures on share-based payment awards, as required by current guidance, or to recognize forfeitures as they occur in addition to other changes. The guidance became effective for interim and annual periods beginning after December 15, 2016. We adopted this standard effective January 1, 2017. We elected to recognize forfeitures on share-based payment awards as they occur. The adoption, along with the remaining provisions of ASU 2016-09, did not have a material impact on our consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory, which requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance is effective for annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the beginning of an annual reporting period. The new standard must be adopted using a modified retrospective transition method, with the cumulative effect recognized as of the date of initial adoption. Effective January 1, 2017, we adopted this standard. The adoption of this new guidance did not have a material impact on our consolidated financial statements. New 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. The FASB has issued several amendments and updates to the new revenue standard, including guidance related to when an entity should recognize revenue gross as a principal or net as an agent and how an entity should identify performance obligations. As amended, ASU 2014-09 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. Early adoption is permitted for all entities only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. We adopted this guidance as of January 1, 2018, utilizing the modified retrospective transition method only with respect to contracts that were not completed as of January 1, 2018. This transition adjustment will be recorded as a one-time decrease to the opening balance of our accumulated deficit as of January 1, 2018 and will be comprised of the following revenue and cost items. The adoption of ASC 606 will require us to recognize revenue from certain of our professional services over time rather than upon completion of the services. We expect this change will result in some acceleration of revenue recognition. We have determined that an agreement to purchase our professional services constitutes an option to purchase services in accordance with ASC 606-10-55-41 rather than an agreement that creates enforceable rights and obligations because of the customer’s contractual right to cancel the unused services. We have determined that certain of our professional service agreements do not contain a material right and are only accounted for in accordance with ASC 606 when the customer exercises its option to purchase additional goods or services. In the case of agreements where we have determined that the option provides the customer with a material right, we will be required to allocate a portion of the transaction price to the material right. The treatment of customer options under ASC 606 may result in a different allocation of the transaction price than under current guidance. In addition, under current guidance, the amount that is allocated to, and recognized as revenue related to, a delivered service is limited to the amount that is not contingent on completion of the remaining performance obligations. We expect the removal of this limitation on contingent revenue under ASC 606 to result in revenue being recognized earlier for certain contracts. In addition, ASU 2014-09 requires that all incremental costs of obtaining a contract with a customer be recognized as an asset. The guidance also requires that these costs be deferred over a term that is consistent with the transfer of services related to the asset. Based on our preliminary analysis, we believe this term will be approximately three years compared to one year or less under current guidance. We elected to apply this guidance to the incremental costs related to open contracts as of January 1, 2018. We expect to record a $5.3 million adjustment to the opening balance of our accumulated deficit to capitalize additional costs of obtaining a contract as of January 1, 2018. Under ASC 606, in addition to recording deferred revenue when the related cash payments are received for noncancellable services, we will record deferred revenue when payments are due in advance of our performance of those services. We expect this change will result in an offsetting increase in accounts receivable and deferred revenue. In the fourth quarter of 2017, we substantially completed our project plan to apply the necessary changes to accounting processes, procedures, systems and internal controls, and we plan to finalize our transition adjustment under ASU 2014-09 in the first quarter of 2018. 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 lease assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements. The standard will become effective for interim and annual periods beginning after December 15, 2018, with early adoption permitted. The guidance is required to be adopted at the earliest period presented using a modified retrospective approach. We plan to adopt this guidance on the effective date. We are currently evaluating the impact the provisions will have on our consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. This ASU requires that companies include amounts generally described as restricted cash and restricted cash equivalents, along with cash and cash equivalents, when reconciling the beginning-of-period and end-of-period amounts shown on the statement of cash flows. The ASU is effective for annual reporting periods beginning after December 15, 2017 and interim periods within those annual periods. We are adopting this guidance as of the effective date. The adoption of this guidance is not expected to have a material impact on our consolidated financial statements. 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 reporting periods beginning after December 15, 2017 and interim periods within those annual periods. Early adoption is permitted. We are adopting this guidance as of the effective date. The implementation of this standard is not expected to have a significant impact on our consolidated financial statements.

Marketable Securities (Notes)

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

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


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

At December 31, 2016, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
U.S. treasury debt securities	$	3,503	$	—	$	(5)	$	3,498
U.S. corporate debt securities	7,943		1		(7)		7,937
Money market funds	43,496		—		—		43,496
	$	54,942	$	1	$	(12)	$	54,931
Included in cash and cash equivalents	$	43,496	$	—	$	—	$	43,496
Included in marketable securities	$	11,446	$	1	$	(12)	$	11,435

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, 2017, 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, 2017
	Less than 12 months				12 months or greater
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. treasury debt securities	$	1,976	$	(7)	$	1,099	$	(1)
U.S. corporate debt securities	13,289		(61)		—		—
Total	$	15,265	$	(68)	$	1,099	$	(1)

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, 2017 to hold these investments until the cost basis is recovered.

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

12 Months Ended

Dec. 31, 2017

Supplemental Balance Sheet and Statement of Operations Information [Abstract]

Supplemental Consolidated Balance Sheet and Statement of Operations Information

Property and Equipment, net

Property and equipment, net as of December 31, 2017 and 2016 consisted of (in thousands):


	As of December 31,
	2017		2016
Buildings	$	36,608	$	36,603
Computers, equipment and software	6,277		5,954
Furniture and fixtures	8,428		8,283
Vehicles	97		97
Leasehold improvements	4,669		4,682
	56,079		55,619
Less: accumulated depreciation and amortization	(15,635)		(13,029)
	$	40,444	$	42,590

The following assets included in property and equipment, net were acquired under capital and financing leases (see Note 5) (in thousands):


	As of December 31,
	2017		2016
Buildings	$	36,608	$	36,603
Computers and equipment	666		1,747
	37,274		38,350
Less: accumulated amortization	(5,891)		(5,134)
	$	31,383	$	33,216

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities as of December 31, 2017 and 2016 consisted of (in thousands):


	As of December 31,
	2017		2016
Accrued vacation	$	6,087	$	4,368
Accrued commissions	3,297		2,382
Accrued bonuses	4,419		8,927
Estimated health insurance claims	1,090		1,210
ESPP employee contributions	1,419		—
Accrued other liabilities	3,900		3,808
	$	20,212	$	20,695

Other Income, net

Other income, net for the years ended December 31, 2017, 2016 and 2015 consisted of (in thousands):


	For the year ended December 31,
	2017		2016		2015
Interest income	$	586	$	286	$	151
Recognition of IEDA government grant	—		—		1,638
Income from training reimbursement program	1,578		1,141		744
(Losses) gains on foreign currency transactions	(372)		67		(293)
Other	(9)		6		62
	$	1,783	$	1,500	$	2,302

Fair Value Measurements (Notes)

12 Months Ended

Dec. 31, 2017

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, 2017 and 2016, 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, 2017						Fair Value Measurements as of December 31, 2016
Description	Total		Level 1		Level 2		Total		Level 1		Level 2
Money market funds	$	49,452	$	49,452	$	—	$	43,496	$	43,496	$	—
U.S. treasury debt securities	3,075		—		3,075		3,498		—		3,498
U.S. corporate debt securities	13,289		—		13,289		7,937		—		7,937
	$	65,816	$	49,452	$	16,364	$	54,931	$	43,496	$	11,435

Included in cash and cash equivalents	$	49,452					$	43,496
Included in marketable securities	$	16,364					$	11,435

- 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

Commitments and Contingencies (Notes)

12 Months Ended

Dec. 31, 2017

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, 2017, 2016 and 2015 was $4.7 million, $3.9 million and $3.7 million, respectively.

In January 2018, we signed a new lease for approximately 30,000 square feet that will replace our existing offices in Denver and Boulder. The aggregate annual payments under the new lease will be approximately $1.0 million and are subject to annual increases over the lease term, which expires in February 2029.

We lease computer equipment under capital lease agreements that expire through September 2018. The total amount financed under these capital leases was $0.5 million during the year ended December 31, 2015. No new assets were financed under capital leases during the years ended December 31, 2017 and 2016.

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 pursuant to ASC 840, Leases, 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, 2017, future estimated minimum lease payments under non-cancelable operating, capital and financing leases were as follows (in thousands):


	Operating Leases		Capital Leases		Financing Obligations
2018	$	3,659	$	66	$	2,792
2019	2,630		—		2,792
2020	2,235		—		2,792
2021	2,187		—		2,792
2022	1,887		—		2,564
Thereafter	6,246		—		25,650
Total minimum lease payments	$	18,844	66		39,382
Less: Amount representing interest			(2)		(19,853)
Present value of capital lease and financing obligations			$	64	$	19,529

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 divert 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. To date, we have entered into five agreements under this program. In addition, we have been reimbursed for training costs incurred for a total of 410 employees.

During the years ended December 31, 2017, 2016 and 2015, we were reimbursed $52,000, $83,000 and $0, respectively. We have concluded that the realization of these amounts 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. We release the liability to “Other income, net” on our statement of operations once the amounts diverted and paid to the community college have reduced the total principal and interest due on the certificates to a level below the amounts reimbursed to date. The amount recognized in other income is measured as the excess of the reimbursements received as of each balance sheet date over the total principal and interest due on the certificates, net of amounts diverted. To the extent we have not diverted amounts sufficient to reduce the principal and interest on the certificates to a level below the reimbursements received for each of the programs, there is no benefit recorded in the statement of operations.

During the years ended December 31, 2017, 2016 and 2015, the total benefit recorded on the statement of operations was $1.6 million, $1.0 million and $744,000, respectively. At December 31, 2017 and 2016, there was $261,000 and $1.8 million included in “Deferred government grant obligation” on the consolidated balance sheet, respectively. The deferred liability is classified as current or non-current based on the estimated timing of when the amounts will be recorded as income. At December 31, 2017 and 2016, there was $217,000 and $1.0 million classified as a current liability, respectively.

In February 2011, we received financing from the Iowa Economic Development Authority (IEDA) that provided for a grant in the form of a forgivable loan totaling $2.3 million. In December 2015, after completing the project close out procedures, IEDA determined that 10 of the 251 positions originally hired under this grant did not meet minimum wage requirements resulting in a repayment of $88,000. The remaining balance under the forgivable loan portion of this government grant of $2.2 million was recognized during the fourth quarter of 2015, with $608,000 recorded as a reduction of our property and equipment and $1.6 million included in “Other income, net” on the consolidated statement of operations. At December 31, 2017 and 2016, there were no amounts outstanding related to the forgivable loan included in “Deferred government grant obligation” on the consolidated balance sheet.

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. The agreement provides that we are committed to pay $4.1 million and $4.8 million during the years ended December 31, 2018 and 2019, respectively.

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. 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 (Notes)	12 Months Ended
Debt (Notes)	Dec. 31, 2017
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 2018. 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 4.5% at December 31, 2017. We recorded no interest expense for the years ended December 31, 2017, 2016 and 2015 related to such debt agreement. No amounts were outstanding under the credit facility as of December 31, 2017 and 2016.

Stockholders' Equity (Deficit) (Notes)	12 Months Ended
Stockholders' Equity (Deficit) (Notes)	Dec. 31, 2017
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 (Notes)

12 Months Ended

Dec. 31, 2017

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, 2017, 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, stockholders approved an amendment to the 2014 Plan that increased the number of shares available for grant by 3,900,000. As of December 31, 2017, 1,999,415 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, 2017, 5,000,000 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. The ESPP’s initial offering period began in July 2017. As of December 31, 2017, we held employee contributions of approximately $1.4 million for future purchases under the ESPP included within accrued expenses and other current liabilities on the consolidated balance sheet. Accordingly, no shares of Class A common stock had been purchased or distributed pursuant to the ESPP as of December 31, 2017.

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,
	2017		2016		2015
Cost of revenue
Subscription and support	$	738	$	493	$	363
Professional services	465		411		349
Operating expenses
Research and development	2,224		2,365		1,924
Sales and marketing	2,983		2,075		1,727
General and administrative	13,066		8,903		6,637
Total	$	19,476	$	14,247	$	11,000

The fair value of each option grant and ESPP purchase right 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,
	2017	2016	2015
Stock Options
Expected term (in years)	0.2 - 6.1	6.0 - 6.1	6.1
Risk-free interest rate	1.5% - 2.2%	1.2% - 2.1%	1.4% - 1.9%
Expected volatility	23.7% - 43.8%	43.0% - 45.3%	42.4% - 47.1%

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

Stock Options

The following table summarizes the option activity under the Plans for the year ended December 31, 2017:


	Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Outstanding at December 31, 2016	7,532,455	$	12.22	7.2	$	19,988
Granted	2,111,253	16.10
Forfeited	(339,111)	14.93
Exercised	(1,158,820)	10.77
Outstanding at December 31, 2017	8,145,777	$	13.33	7.0	$	65,913

Exercisable at December 31, 2017	4,607,812	$	11.49	5.7	$	45,653

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, 2017, 2016 and 2015 was $9.8 million, $3.9 million and $8.4 million, respectively.

The weighted-average grant-date fair value of options granted during the years ended December 31, 2017, 2016 and 2015 was $6.79, $6.79 and $6.53, respectively. The total fair value of options vested during the years ended December 31, 2017, 2016 and 2015 was approximately $10.2 million, $9.3 million and $8.7 million, respectively. Total unrecognized compensation expense of $19.7 million related to options will be recognized over a weighted-average period of 2.5 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 and to non-employee members of our Board of Directors with one-year cliff vesting 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, 2017, 2016, and 2015 was approximately $2.7 million, $3.3 million, and $750,000 respectively.

The following table summarizes the restricted stock award activity under the Plan for the year ended December 31, 2017:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2016	353,335	$	13.40
Granted	—	—
Forfeited	—	—
Vested	(190,003)	13.40
Unvested at December 31, 2017	163,332	$	13.40

Compensation expense associated with unvested restricted stock awards is recognized on a straight-line basis over the vesting period. At December 31, 2017, there was approximately $0.2 million of total unrecognized compensation expense related to restricted stock awards, which is expected to be recognized over a weighted-average period of 0.1 years.

Restricted Stock Units

We have granted restricted stock units to our executive officers that vest in three equal annual installments from the date of grant and to non-employee members of our Board of Directors with 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 year ended December 31, 2017 was approximately $3.6 million. No restricted stock units vested during the years ended December 31, 2016 or 2015.

The following table summarizes the restricted stock unit activity under the Plan for the year ended December 31, 2017:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2016	381,952	$	15.11
Granted	413,792	13.95
Forfeited	—	—
Vested⁽¹⁾	(221,672)	14.48
Unvested at December 31, 2017	574,072	$	14.51

(1) As of December 31, 2017, recipients of 191,485 shares had elected to defer settlement of the vested restricted stock units in accordance with our Nonqualified Deferred Compensation Plan.

Compensation expense associated with unvested restricted stock units is recognized on a straight-line basis over the vesting period. At December 31, 2017, there was approximately $5.0 million of total unrecognized compensation expense related to restricted stock units, which is expected to be recognized over a weighted-average period of 1.6 years.

Employee Stock Purchase Plan

Compensation expense associated with ESPP purchase rights is recognized on a straight-line basis over the vesting period. At December 31, 2017, there was approximately $27,000 of total unrecognized compensation expense related to the ESPP, which is expected to be recognized over a weighted-average period of 0.03 years.

Accumulated Other Comprehensive Income (Notes)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Accumulated Other Comprehensive Income

The following table summarizes the activity of accumulated other comprehensive income during the years ended December 31, 2017, 2016 and 2015 (in thousands):


	Accumulated translation adjustment		Accumulated unrealized holding gains (losses) on available-for-sale securities		Accumulated other comprehensive income
Balance at December 31, 2014	$	147	$	—	$	147
Other comprehensive income (loss)	133		(39)		94
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

Segments (Notes)	12 Months Ended
Segments (Notes)	Dec. 31, 2017
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, 2017, 2016 and 2015, 92.1%, 93.8% and 94.3% of our revenue, respectively, and substantially all of our long-lived assets were attributable to operations in the United States.

Income Taxes (Notes)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

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


	For the year ended December 31,
	2017		2016		2015
United States	$	(44,246)	$	(43,952)	$	(42,788)
Foreign	(119)		(1)		(618)
Total	$	(44,365)	$	(43,953)	$	(43,406)

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


	For the year ended December 31,
	2017		2016		2015
Current
State	$	42	$	12	$	69
Foreign	19		44		—
Total Current	$	61	$	56	$	69

Deferred
Federal	$	—	$	(32)	$	(76)
Total Deferred	$	—	$	(32)	$	(76)

Total	$	61	$	24	$	(7)

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,
	2017			2016			2015
Federal statutory rate	35.0		%	35.0		%	35.0		%
Effect of:
Tax benefit at federal statutory rate	$	(15,528)		$	(15,384)		$	(15,192)
State taxes, net of federal benefit	(1,802)			(1,377)			(1,833)
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	5,141			1,292			636
Tax benefit of federal R&D credit	(2,366)			(1,781)			(1,270)

Recognition of excess tax benefits related to share-based payments	(3,606)			—			—
Valuation allowance	(8,586)			17,013			17,697
Other	(206)			261			(45)
Total income tax provision	$	61		$	24		$	(7)

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


	As of December 31,
	2017		2016
Deferred tax assets:
Property and equipment	$	15	$	12
Accruals and reserves	199		1,104
Deferred rent	931		1,565
Compensation and benefits	11,973		16,048
Deferred revenue	4,762		3,255
Net operating loss and credits	41,108		45,625
Other	167		180
Total deferred tax assets	59,155		67,789
Valuation allowance	(58,639)		(67,225)
Total deferred tax assets	516		564
Deferred tax liabilities:
Property and equipment	(440)		(403)
Other deferred tax liabilities	(76)		(161)
Deferred tax liabilities	(516)		(564)
Total	$	—	$	—

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 makes 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. The carrying value of our deferred tax assets and liabilities is also determined by the enacted U.S. corporate income tax rate. Consequently, any changes in the U.S. corporate income tax rate will impact the carrying value of our deferred tax assets and liabilities. Under the new corporate income tax rate of 21%, deferred income tax assets, net have decreased by $22.9 million and the valuation allowance has decreased by $22.9 million. There was no net effect of the tax reform enactment on the financial statements as of December 31, 2017.

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. Further adjustments, if any, will be 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.

Effective July 1, 2017, the Company completed a restructuring of its foreign operations. A newly formed holding company was set up in the United Kingdom, Workiva Holdings Limited, which will be treated as a controlled foreign corporation from a U.S. income tax perspective. The outstanding stock ownership of the existing foreign subsidiaries were contributed to Workiva Holdings Limited, effective July 1, 2017, which triggered a taxable gain for the difference in fair market value compared to the tax basis in the entities for U.S. income tax purposes. The estimated gain recorded is $13.9 million which is included as a permanent book-tax difference. The gain is expected to be fully offset by current year net operating losses.

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, 2017. 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 deferred tax asset at December 31, 2017, because we believe it is more likely than not that these benefits will not be realized.

As of December 31, 2017, we have federal and state net operating loss carryforwards of approximately $133.8 million and $101.2 million, respectively, available to reduce any future taxable income. The federal net operating loss carryforwards will expire in varying amounts between years 2034 and 2037. The state net operating loss carryforwards will expire in varying amounts between years 2021 and 2037. Additionally, we have total net operating loss carryforwards from international operations of $480,000 that will expire in varying amounts beginning in 2033. We also have approximately $6.0 million of federal and $1.3 million of state tax credit carryforwards as of December 31, 2017. The federal credits will expire in varying amounts between the years 2034 and 2037. 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,
	2017		2016
Unrecognized tax benefits-beginning of period	$	168	$	—
Additions for tax positions related to prior year	—		168
Reductions for tax positions related to prior year	—		—
Foreign currency adjustments	23		—
Additions for tax positions related to current year	—		—
Unrecognized tax benefits-end of period	$	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, 2017, 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, 2017, 2016 and 2015.

We are subject to taxation in the United States and various states and foreign jurisdictions. As of December 31, 2017, tax years for 2014 through 2017 are subject to examination by the tax authorities. With few exceptions, as of December 31, 2017, 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 (Notes)

12 Months Ended

Dec. 31, 2017

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, 2017				December 31, 2016				December 31, 2015
	Class A		Class B		Class A		Class B		Class A		Class B
Numerator
Net loss	$	(33,016)	$	(11,410)	$	(31,644)	$	(12,333)	$	(30,075)	$	(13,324)

Denominator
Weighted-average common shares outstanding - basic and diluted	30,929,899		10,688,939		29,265,605		11,405,528		27,617,350		12,235,274
Basic and diluted net loss per share	$	(1.07)	$	(1.07)	$	(1.08)	$	(1.08)	$	(1.09)	$	(1.09)

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,
	2017	2016	2015
Shares subject to outstanding common stock options	8,145,777	7,532,455	6,969,133
Shares subject to unvested restricted stock awards	163,332	353,335	600,025
Shares issuable pursuant to the ESPP	85,509	—	—

Unaudited Quarterly Results of Operations (Notes)

12 Months Ended

Dec. 31, 2017

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, 2017		Sep 30, 2017		Jun 30, 2017		Mar 31, 2017		Dec 31, 2016		Sep 30, 2016		Jun 30, 2016		Mar 31, 2016
	(in thousands)
Revenue
Subscription and support	$	45,549	$	43,214	$	40,980	$	39,540	$	38,329	$	36,237	$	34,969	$	33,585
Professional services	8,957		8,854		8,411		12,364		8,045		8,473		8,042		10,966
Total revenue	54,506		52,068		49,391		51,904		46,374		44,710		43,011		44,551
Cost of revenue
Subscription and support	8,779		8,472		7,758		7,637		7,244		6,694		7,039		6,918
Professional services	7,310		7,180		6,528		6,581		5,964		6,040		5,538		6,188
Total cost of revenue	16,089		15,652		14,286		14,218		13,208		12,734		12,577		13,106
Gross profit	38,417		36,416		35,105		37,686		33,166		31,976		30,434		31,445
Operating expenses
Research and development	18,870		17,527		16,239		15,536		14,533		14,342		14,047		14,516
Sales and marketing	21,949		23,712		19,787		18,713		18,196		22,354		19,828		20,088
General and administrative ⁽¹⁾	12,271		8,959		8,943		9,421		7,845		8,015		7,882		8,953
Total operating expenses	53,090		50,198		44,969		43,670		40,574		44,711		41,757		43,557
Loss from operations	(14,673)		(13,782)		(9,864)		(5,984)		(7,408)		(12,735)		(11,323)		(12,112)
Interest expense	(451)		(464)		(475)		(455)		(455)		(462)		(468)		(490)
Other income, net	797		198		176		612		348		298		278		576
Loss before (benefit) provision for income taxes	(14,327)		(14,048)		(10,163)		(5,827)		(7,515)		(12,899)		(11,513)		(12,026)
(Benefit) provision for income taxes	(6)		25		33		9		1		(8)		12		19
Net loss	$	(14,321)	$	(14,073)	$	(10,196)	$	(5,836)	$	(7,516)	$	(12,891)	$	(11,525)	$	(12,045)
Net loss per common share:
Basic and diluted	$	(0.34)	$	(0.34)	$	(0.25)	$	(0.14)	$	(0.18)	$	(0.32)	$	(0.28)	$	(0.30)
Weighted-average common shares outstanding - basic and diluted	42,108,764		41,815,139		41,429,691		41,108,611		40,872,772		40,762,960		40,593,908		40,451,668

(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 (Policies)	12 Months Ended
	Dec. 31, 2017
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. All intercompany accounts and transactions have been eliminated in consolidation.
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’ equity. 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.
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 determination of the relative selling prices of our services, health insurance claims incurred but not yet reported, collectability of accounts receivable, valuation of available-for-sale marketable securities, useful lives of 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 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	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.
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.
Revenue Recognition	We generate revenue through the sale of subscriptions to our cloud-based software and the delivery of professional services. Our customer contracts typically range in length from three to 36 months. Our arrangements do not contain general rights of return. Our subscription contracts do not provide customers with the right to take possession of the software supporting the applications and, as a result, are accounted for as service contracts. We commence revenue recognition for subscriptions to our cloud applications and professional services when all of the following criteria are met: There is persuasive evidence of an arrangement; The service has been or is being provided to the customer; Collection of the fees is reasonably assured; and The amount of fees to be paid by the customer is fixed or determinable. Collectability is assessed based on a number of factors, including past transaction history with the customer and the creditworthiness of the customer. Collateral is not requested from the customer. If it is determined that the collection of a fee is not probable, the revenue is deferred until collection becomes probable, which is generally upon the receipt of cash. Revenue is reported net of sales and other taxes collected from customers to be remitted to government authorities. Subscription and Support Revenue We recognize the aggregate minimum subscription and support fees ratably on a straight-line basis over the subscription term, provided that an enforceable contract has been signed by both parties, access to our SaaS solutions has been granted to the customer, the fee for the subscription and support is fixed or determinable, and collection is reasonably assured. Professional Services Revenue We recognize revenue for our professional services contracts when the services are performed.
Multiple-Deliverable Arrangements	Multiple Deliverable Arrangements For arrangements with multiple deliverables, we evaluate whether the individual deliverables qualify as separate units of accounting. In order to treat deliverables in a multiple deliverable arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. For deliverables that have standalone value upon delivery, we account for each deliverable separately and recognize revenue for the respective deliverables as they are delivered. Subscription contracts have standalone value as we sell the subscriptions separately. In determining whether professional services can be accounted for separately from subscription services, we consider the availability of the professional services from other vendors, the nature of our professional services and whether we sell our applications to new customers without professional services. In the years ended December 31, 2017, 2016 and 2015, we determined that we had established standalone value for our professional services. This determination was made due primarily to the ability of the customer to complete these tasks without assistance and the sale of services separate from the initial subscription order. Because we established standalone value for our professional services in the years ended December 31, 2017, 2016 and 2015, such service arrangements are being accounted for separately from subscription services. When multiple deliverables included in an arrangement are separable into different units of accounting, the arrangement consideration is allocated to the identified separate units of accounting based on their relative selling price. Multiple deliverable arrangements accounting guidance provides a hierarchy to use when determining the relative selling price for each unit of accounting. Vendor-specific objective evidence (VSOE) of selling price, based on the price at which the item is regularly sold by the vendor on a standalone basis, should be used if it exists. If VSOE of selling price is not available, third-party evidence (TPE) of selling price is used to establish the selling price if it exists. VSOE and TPE do not currently exist for any of our deliverables. Accordingly, for arrangements with multiple deliverables that can be separated into different units of accounting, we allocate the arrangement fee to the separate units of accounting based on our best estimate of selling price. The amount of arrangement fee allocated is limited by contingent revenue, if any. We determine our best estimate of selling price for our deliverables based on our overall pricing objectives, taking into consideration market conditions and entity-specific factors. We evaluate our best estimate of selling price by reviewing historical data related to sales of our deliverables, including comparing the percentages of our contract prices to our list prices. We also may consider several other data points in our evaluation, including the size of our arrangements, length of term, the cloud applications sold, customer demographics and the numbers and types of users within our arrangements.
Deferred Revenue	We typically invoice our customers for subscription 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 services starting in future periods are excluded from accounts receivable and deferred revenue. Invoiced amounts are reflected as accounts receivable once we have initiated services with an offset to deferred revenue or revenue depending on whether the revenue recognition criteria have been met. Deferred revenue also includes certain deferred professional service fees that are recognized upon completion of the service. 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.
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 and Deferred Commissions	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. We amortize sales commissions that are directly attributable to a contract over the lesser of 12 months or the non-cancelable term of the customer contract based on the terms of our commission arrangements.
Advertising Costs	Advertising costs are charged to sales and marketing expense as incurred.
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. Leasehold improvements are capitalized at cost and amortized over the shorter of their useful life or the term of the lease.
Government Grants	Government grants received are recorded as a liability on the balance sheet 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.
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.
Share-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. 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 makes 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 we become subject to GILTI. 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 statement of operations. Accrued interest and penalties are included on the related tax liability line in the consolidated balance sheet.
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.
New Accounting Pronouncements	Recently Adopted Accounting Pronouncements In March 2016, the FASB issued ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. Under this ASU, entities are permitted to make an accounting policy election either to estimate forfeitures on share-based payment awards, as required by current guidance, or to recognize forfeitures as they occur in addition to other changes. The guidance became effective for interim and annual periods beginning after December 15, 2016. We adopted this standard effective January 1, 2017. We elected to recognize forfeitures on share-based payment awards as they occur. The adoption, along with the remaining provisions of ASU 2016-09, did not have a material impact on our consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory, which requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance is effective for annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the beginning of an annual reporting period. The new standard must be adopted using a modified retrospective transition method, with the cumulative effect recognized as of the date of initial adoption. Effective January 1, 2017, we adopted this standard. The adoption of this new guidance did not have a material impact on our consolidated financial statements. New 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. The FASB has issued several amendments and updates to the new revenue standard, including guidance related to when an entity should recognize revenue gross as a principal or net as an agent and how an entity should identify performance obligations. As amended, ASU 2014-09 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. Early adoption is permitted for all entities only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. We adopted this guidance as of January 1, 2018, utilizing the modified retrospective transition method only with respect to contracts that were not completed as of January 1, 2018. This transition adjustment will be recorded as a one-time decrease to the opening balance of our accumulated deficit as of January 1, 2018 and will be comprised of the following revenue and cost items. The adoption of ASC 606 will require us to recognize revenue from certain of our professional services over time rather than upon completion of the services. We expect this change will result in some acceleration of revenue recognition. We have determined that an agreement to purchase our professional services constitutes an option to purchase services in accordance with ASC 606-10-55-41 rather than an agreement that creates enforceable rights and obligations because of the customer’s contractual right to cancel the unused services. We have determined that certain of our professional service agreements do not contain a material right and are only accounted for in accordance with ASC 606 when the customer exercises its option to purchase additional goods or services. In the case of agreements where we have determined that the option provides the customer with a material right, we will be required to allocate a portion of the transaction price to the material right. The treatment of customer options under ASC 606 may result in a different allocation of the transaction price than under current guidance. In addition, under current guidance, the amount that is allocated to, and recognized as revenue related to, a delivered service is limited to the amount that is not contingent on completion of the remaining performance obligations. We expect the removal of this limitation on contingent revenue under ASC 606 to result in revenue being recognized earlier for certain contracts. In addition, ASU 2014-09 requires that all incremental costs of obtaining a contract with a customer be recognized as an asset. The guidance also requires that these costs be deferred over a term that is consistent with the transfer of services related to the asset. Based on our preliminary analysis, we believe this term will be approximately three years compared to one year or less under current guidance. We elected to apply this guidance to the incremental costs related to open contracts as of January 1, 2018. We expect to record a $5.3 million adjustment to the opening balance of our accumulated deficit to capitalize additional costs of obtaining a contract as of January 1, 2018. Under ASC 606, in addition to recording deferred revenue when the related cash payments are received for noncancellable services, we will record deferred revenue when payments are due in advance of our performance of those services. We expect this change will result in an offsetting increase in accounts receivable and deferred revenue. In the fourth quarter of 2017, we substantially completed our project plan to apply the necessary changes to accounting processes, procedures, systems and internal controls, and we plan to finalize our transition adjustment under ASU 2014-09 in the first quarter of 2018. 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 lease assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements. The standard will become effective for interim and annual periods beginning after December 15, 2018, with early adoption permitted. The guidance is required to be adopted at the earliest period presented using a modified retrospective approach. We plan to adopt this guidance on the effective date. We are currently evaluating the impact the provisions will have on our consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. This ASU requires that companies include amounts generally described as restricted cash and restricted cash equivalents, along with cash and cash equivalents, when reconciling the beginning-of-period and end-of-period amounts shown on the statement of cash flows. The ASU is effective for annual reporting periods beginning after December 15, 2017 and interim periods within those annual periods. We are adopting this guidance as of the effective date. The adoption of this guidance is not expected to have a material impact on our consolidated financial statements. 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 reporting periods beginning after December 15, 2017 and interim periods within those annual periods. Early adoption is permitted. We are adopting this guidance as of the effective date. The implementation of this standard is not expected to have a significant impact on our consolidated financial statements.

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of Marketable Securities

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


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

At December 31, 2016, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
U.S. treasury debt securities	$	3,503	$	—	$	(5)	$	3,498
U.S. corporate debt securities	7,943		1		(7)		7,937
Money market funds	43,496		—		—		43,496
	$	54,942	$	1	$	(12)	$	54,931
Included in cash and cash equivalents	$	43,496	$	—	$	—	$	43,496
Included in marketable securities	$	11,446	$	1	$	(12)	$	11,435

Schedule of Cash and Cash Equivalents

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


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

At December 31, 2016, marketable securities consisted of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Fair Value
U.S. treasury debt securities	$	3,503	$	—	$	(5)	$	3,498
U.S. corporate debt securities	7,943		1		(7)		7,937
Money market funds	43,496		—		—		43,496
	$	54,942	$	1	$	(12)	$	54,931
Included in cash and cash equivalents	$	43,496	$	—	$	—	$	43,496
Included in marketable securities	$	11,446	$	1	$	(12)	$	11,435

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


	As of December 31, 2017
	Less than 12 months				12 months or greater
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. treasury debt securities	$	1,976	$	(7)	$	1,099	$	(1)
U.S. corporate debt securities	13,289		(61)		—		—
Total	$	15,265	$	(68)	$	1,099	$	(1)

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

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

12 Months Ended

Dec. 31, 2017

Supplemental Balance Sheet and Statement of Operations Information [Abstract]

Schedule of Property, Plant and Equipment

Property and equipment, net as of December 31, 2017 and 2016 consisted of (in thousands):


	As of December 31,
	2017		2016
Buildings	$	36,608	$	36,603
Computers, equipment and software	6,277		5,954
Furniture and fixtures	8,428		8,283
Vehicles	97		97
Leasehold improvements	4,669		4,682
	56,079		55,619
Less: accumulated depreciation and amortization	(15,635)		(13,029)
	$	40,444	$	42,590

Schedule of Capital Leased Assets

The following assets included in property and equipment, net were acquired under capital and financing leases (see Note 5) (in thousands):


	As of December 31,
	2017		2016
Buildings	$	36,608	$	36,603
Computers and equipment	666		1,747
	37,274		38,350
Less: accumulated amortization	(5,891)		(5,134)
	$	31,383	$	33,216

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities as of December 31, 2017 and 2016 consisted of (in thousands):


	As of December 31,
	2017		2016
Accrued vacation	$	6,087	$	4,368
Accrued commissions	3,297		2,382
Accrued bonuses	4,419		8,927
Estimated health insurance claims	1,090		1,210
ESPP employee contributions	1,419		—
Accrued other liabilities	3,900		3,808
	$	20,212	$	20,695

Schedule of Other Income and (Expense), net

Other income, net for the years ended December 31, 2017, 2016 and 2015 consisted of (in thousands):


	For the year ended December 31,
	2017		2016		2015
Interest income	$	586	$	286	$	151
Recognition of IEDA government grant	—		—		1,638
Income from training reimbursement program	1,578		1,141		744
(Losses) gains on foreign currency transactions	(372)		67		(293)
Other	(9)		6		62
	$	1,783	$	1,500	$	2,302

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities 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, 2017						Fair Value Measurements as of December 31, 2016
Description	Total		Level 1		Level 2		Total		Level 1		Level 2
Money market funds	$	49,452	$	49,452	$	—	$	43,496	$	43,496	$	—
U.S. treasury debt securities	3,075		—		3,075		3,498		—		3,498
U.S. corporate debt securities	13,289		—		13,289		7,937		—		7,937
	$	65,816	$	49,452	$	16,364	$	54,931	$	43,496	$	11,435

Included in cash and cash equivalents	$	49,452					$	43,496
Included in marketable securities	$	16,364					$	11,435

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments

As of December 31, 2017, future estimated minimum lease payments under non-cancelable operating, capital and financing leases were as follows (in thousands):


	Operating Leases		Capital Leases		Financing Obligations
2018	$	3,659	$	66	$	2,792
2019	2,630		—		2,792
2020	2,235		—		2,792
2021	2,187		—		2,792
2022	1,887		—		2,564
Thereafter	6,246		—		25,650
Total minimum lease payments	$	18,844	66		39,382
Less: Amount representing interest			(2)		(19,853)
Present value of capital lease and financing obligations			$	64	$	19,529

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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,
	2017		2016		2015
Cost of revenue
Subscription and support	$	738	$	493	$	363
Professional services	465		411		349
Operating expenses
Research and development	2,224		2,365		1,924
Sales and marketing	2,983		2,075		1,727
General and administrative	13,066		8,903		6,637
Total	$	19,476	$	14,247	$	11,000

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,
	2017	2016	2015
Stock Options
Expected term (in years)	0.2 - 6.1	6.0 - 6.1	6.1
Risk-free interest rate	1.5% - 2.2%	1.2% - 2.1%	1.4% - 1.9%
Expected volatility	23.7% - 43.8%	43.0% - 45.3%	42.4% - 47.1%

ESPP
Expected term (in years)	0.5	—	—
Risk-free interest rate	1.2%	—%	—%
Expected volatility	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,
	2017	2016	2015
Stock Options
Expected term (in years)	0.2 - 6.1	6.0 - 6.1	6.1
Risk-free interest rate	1.5% - 2.2%	1.2% - 2.1%	1.4% - 1.9%
Expected volatility	23.7% - 43.8%	43.0% - 45.3%	42.4% - 47.1%

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

Schedule of Stock-Option Activity

The following table summarizes the option activity under the Plans for the year ended December 31, 2017:


	Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Outstanding at December 31, 2016	7,532,455	$	12.22	7.2	$	19,988
Granted	2,111,253	16.10
Forfeited	(339,111)	14.93
Exercised	(1,158,820)	10.77
Outstanding at December 31, 2017	8,145,777	$	13.33	7.0	$	65,913

Exercisable at December 31, 2017	4,607,812	$	11.49	5.7	$	45,653

Schedule of Restricted Stock Awards

The following table summarizes the restricted stock award activity under the Plan for the year ended December 31, 2017:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2016	353,335	$	13.40
Granted	—	—
Forfeited	—	—
Vested	(190,003)	13.40
Unvested at December 31, 2017	163,332	$	13.40

Schedule of Restricted Stock Units

The following table summarizes the restricted stock unit activity under the Plan for the year ended December 31, 2017:


	Number of Shares	Weighted-Average Grant Date Fair Value

Unvested at December 31, 2016	381,952	$	15.11
Granted	413,792	13.95
Forfeited	—	—
Vested⁽¹⁾	(221,672)	14.48
Unvested at December 31, 2017	574,072	$	14.51

Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2017

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, 2017, 2016 and 2015 (in thousands):


	Accumulated translation adjustment		Accumulated unrealized holding gains (losses) on available-for-sale securities		Accumulated other comprehensive income
Balance at December 31, 2014	$	147	$	—	$	147
Other comprehensive income (loss)	133		(39)		94
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

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Loss Before Income Tax Provision

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


	For the year ended December 31,
	2017		2016		2015
United States	$	(44,246)	$	(43,952)	$	(42,788)
Foreign	(119)		(1)		(618)
Total	$	(44,365)	$	(43,953)	$	(43,406)

Schedule of Provision (Benefit) for Income Taxes

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


	For the year ended December 31,
	2017		2016		2015
Current
State	$	42	$	12	$	69
Foreign	19		44		—
Total Current	$	61	$	56	$	69

Deferred
Federal	$	—	$	(32)	$	(76)
Total Deferred	$	—	$	(32)	$	(76)

Total	$	61	$	24	$	(7)

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,
	2017			2016			2015
Federal statutory rate	35.0		%	35.0		%	35.0		%
Effect of:
Tax benefit at federal statutory rate	$	(15,528)		$	(15,384)		$	(15,192)
State taxes, net of federal benefit	(1,802)			(1,377)			(1,833)
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	5,141			1,292			636
Tax benefit of federal R&D credit	(2,366)			(1,781)			(1,270)

Recognition of excess tax benefits related to share-based payments	(3,606)			—			—
Valuation allowance	(8,586)			17,013			17,697
Other	(206)			261			(45)
Total income tax provision	$	61		$	24		$	(7)

Schedule of Deferred Tax Assets and Liabilities

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


	As of December 31,
	2017		2016
Deferred tax assets:
Property and equipment	$	15	$	12
Accruals and reserves	199		1,104
Deferred rent	931		1,565
Compensation and benefits	11,973		16,048
Deferred revenue	4,762		3,255
Net operating loss and credits	41,108		45,625
Other	167		180
Total deferred tax assets	59,155		67,789
Valuation allowance	(58,639)		(67,225)
Total deferred tax assets	516		564
Deferred tax liabilities:
Property and equipment	(440)		(403)
Other deferred tax liabilities	(76)		(161)
Deferred tax liabilities	(516)		(564)
Total	$	—	$	—

Schedule of Unrecognized Tax Benefits

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


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

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2017

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, 2017				December 31, 2016				December 31, 2015
	Class A		Class B		Class A		Class B		Class A		Class B
Numerator
Net loss	$	(33,016)	$	(11,410)	$	(31,644)	$	(12,333)	$	(30,075)	$	(13,324)

Denominator
Weighted-average common shares outstanding - basic and diluted	30,929,899		10,688,939		29,265,605		11,405,528		27,617,350		12,235,274
Basic and diluted net loss per share	$	(1.07)	$	(1.07)	$	(1.08)	$	(1.08)	$	(1.09)	$	(1.09)

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,
	2017	2016	2015
Shares subject to outstanding common stock options	8,145,777	7,532,455	6,969,133
Shares subject to unvested restricted stock awards	163,332	353,335	600,025
Shares issuable pursuant to the ESPP	85,509	—	—

Unaudited Quarterly Results of Operations (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information


	Three months ended
	Dec 31, 2017		Sep 30, 2017		Jun 30, 2017		Mar 31, 2017		Dec 31, 2016		Sep 30, 2016		Jun 30, 2016		Mar 31, 2016
	(in thousands)
Revenue
Subscription and support	$	45,549	$	43,214	$	40,980	$	39,540	$	38,329	$	36,237	$	34,969	$	33,585
Professional services	8,957		8,854		8,411		12,364		8,045		8,473		8,042		10,966
Total revenue	54,506		52,068		49,391		51,904		46,374		44,710		43,011		44,551
Cost of revenue
Subscription and support	8,779		8,472		7,758		7,637		7,244		6,694		7,039		6,918
Professional services	7,310		7,180		6,528		6,581		5,964		6,040		5,538		6,188
Total cost of revenue	16,089		15,652		14,286		14,218		13,208		12,734		12,577		13,106
Gross profit	38,417		36,416		35,105		37,686		33,166		31,976		30,434		31,445
Operating expenses
Research and development	18,870		17,527		16,239		15,536		14,533		14,342		14,047		14,516
Sales and marketing	21,949		23,712		19,787		18,713		18,196		22,354		19,828		20,088
General and administrative ⁽¹⁾	12,271		8,959		8,943		9,421		7,845		8,015		7,882		8,953
Total operating expenses	53,090		50,198		44,969		43,670		40,574		44,711		41,757		43,557
Loss from operations	(14,673)		(13,782)		(9,864)		(5,984)		(7,408)		(12,735)		(11,323)		(12,112)
Interest expense	(451)		(464)		(475)		(455)		(455)		(462)		(468)		(490)
Other income, net	797		198		176		612		348		298		278		576
Loss before (benefit) provision for income taxes	(14,327)		(14,048)		(10,163)		(5,827)		(7,515)		(12,899)		(11,513)		(12,026)
(Benefit) provision for income taxes	(6)		25		33		9		1		(8)		12		19
Net loss	$	(14,321)	$	(14,073)	$	(10,196)	$	(5,836)	$	(7,516)	$	(12,891)	$	(11,525)	$	(12,045)
Net loss per common share:
Basic and diluted	$	(0.34)	$	(0.34)	$	(0.25)	$	(0.14)	$	(0.18)	$	(0.32)	$	(0.28)	$	(0.30)
Weighted-average common shares outstanding - basic and diluted	42,108,764		41,815,139		41,429,691		41,108,611		40,872,772		40,762,960		40,593,908		40,451,668

(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, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
(Losses) gains on foreign currency transactions	$ (372)	$ 67	$ (293)

Organization and Significant Accounting Policies - Property and Equipment, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation	$ 3.4	$ 3.7	$ 4.4
Capital lease amortization expense	$ 1.6	$ 2.1	$ 2.4
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	10 years

Organization and Significant Accounting Policies - Revenue Recognition and Sales and Marketing Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue recognition, customer contract period, min	3 months
Revenue recognition, customer contract period, max	36 months
Sales commissions amortization period	12 months
Advertising expense	$ 2.7	$ 2.7	$ 2.8

Organization and Significant Accounting Policies - Intangible Assets (Details) - Patents - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets useful life	10 years
Finite-lived intangible assets, accumulated amortization	$ 218	$ 127
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2018	94
2019	94
2020	94
2021	94
2022	94
Thereafter	$ 211

Organization and Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized cost, amortization period under new and existing guidance		1 year
Accounting Standards Update 2014-09 \| Subsequent event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized cost, amortization period under new and existing guidance	3 years
Increase in capitalized contract costs	$ 5.3

Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 60,333	$ 51,281	$ 58,750	$ 101,131
Available-for-sale Securities [Abstract]
Unrealized Gains	0	1
Unrealized Losses	(69)	(12)
Cash and cash equivalents and available-for-sale securities, amortized cost	65,885	54,942
Cash and cash equivalents and available-for-sale securities	65,816	54,931
U.S. treasury debt securities
Available-for-sale Securities [Abstract]
Amortized Cost	3,083	3,503
Unrealized Gains	0	0
Unrealized Losses	(8)	(5)
Aggregate Fair Value	3,075	3,498
U.S. corporate debt securities
Available-for-sale Securities [Abstract]
Amortized Cost	13,350	7,943
Unrealized Gains	0	1
Unrealized Losses	(61)	(7)
Aggregate Fair Value	13,289	7,937
Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	49,452	43,496
Cash and cash equivalents, aggregate fair value	49,452	43,496
Cash and Cash Equivalents \| Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	49,452	43,496
Cash and cash equivalents, aggregate fair value	49,452	43,496
Marketable Securities \| U.S. corporate debt securities
Available-for-sale Securities [Abstract]
Amortized Cost	16,433	11,446
Unrealized Gains	0	1
Unrealized Losses	(69)	(12)
Aggregate Fair Value	$ 16,364	$ 11,435

Marketable Securities - Continuous Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Fair Value:
Less than 12 months	$ 15,265
12 months or greater	1,099
Unrealized Loss:
Less than 12 months	(68)
12 months or greater	(1)
U.S. treasury debt securities
Fair Value:
Less than 12 months	1,976
12 months or greater	1,099
Unrealized Loss:
Less than 12 months	(7)
12 months or greater	(1)
U.S. corporate debt securities
Fair Value:
Less than 12 months	13,289
12 months or greater	0
Unrealized Loss:
Less than 12 months	(61)
12 months or greater	$ 0

Supplemental Consolidated Balance Sheet and Statement of Operations Information - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014	Jun. 30, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 56,079	$ 55,619
Less: accumulated depreciation and amortization	(15,635)	(13,029)
Property and equipment, net	40,444	42,590
Capital and financing leased assets, gross	37,274	38,350
Less: accumulated amortization	(5,891)	(5,134)
Capital and financing leases, net	31,383	33,216
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	36,608	36,603	$ 19,900	$ 17,100
Capital and financing leased assets, gross	36,608	36,603
Computers, equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,277	5,954
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	8,428	8,283
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	4,669	4,682
Computers and equipment
Property, Plant and Equipment [Line Items]
Capital and financing leased assets, gross	$ 666	$ 1,747

Supplemental Consolidated Balance Sheet and Statement of Operations Information - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Accrued vacation	$ 6,087	$ 4,368
Accrued commissions	3,297	2,382
Accrued bonuses	4,419	8,927
Estimated health insurance claims	1,090	1,210
ESPP employee contributions	1,419	0
Accrued other liabilities	3,900	3,808
Accrued expenses and other current liabilities	$ 20,212	$ 20,695

Supplemental Consolidated Balance Sheet and Statement of Operations Information - Other Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Nonoperating Income (Expense) [Abstract]
Interest income									$ 586	$ 286	$ 151
Recognition of IEDA government grant									0	0	1,638
Income from training reimbursement program									1,578	1,141	744
(Losses) gains on foreign currency transactions									(372)	67	(293)
Other									(9)	6	62
Nonoperating Income (Expense)	$ 797	$ 198	$ 176	$ 612	$ 348	$ 298	$ 278	$ 576	$ 1,783	$ 1,500	$ 2,302

Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 3,075	$ 3,498
U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13,289	7,937
U.S. corporate debt securities \| Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,364	11,435
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	49,452	43,496
Money market funds \| Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	49,452	43,496
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	65,816	54,931
Recurring \| Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	49,452	43,496
Recurring \| Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,364	11,435
Recurring \| U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	3,075	3,498
Recurring \| U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13,289	7,937
Recurring \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	49,452	43,496
Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	49,452	43,496
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 equivalents - money market funds	49,452	43,496
Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	16,364	11,435
Recurring \| Level 2 \| U.S. treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	3,075	3,498
Recurring \| Level 2 \| U.S. corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13,289	7,937
Recurring \| Level 2 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents - money market funds	$ 0	$ 0

Commitments and Contingencies - Lease Commitments (Details) ft² in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jan. 31, 2018 USD ($) ft²
Property, Plant and Equipment [Line Items]
Operating lease rent expense	$ 4,700,000	$ 3,900,000	$ 3,700,000
Capital leased assets	37,274,000	38,350,000
COLORADO \| Subsequent event
Property, Plant and Equipment [Line Items]
New lease agreement, area of property (in square feet) \| ft²				30
Aggregate annual payment under new lease				$ 1,000,000.0
Computer Equipment and Furniture
Property, Plant and Equipment [Line Items]
Capital leased assets	$ 0	$ 0	$ 500,000

Commitments and Contingencies - Build to Suit (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) phase	Dec. 31, 2016 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2013 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Financing obligation number of phases \| phase	2
Financing obligation, lessor committed fundings phase 1	$ 11,800
Financing obligation, lessor committed fundings phase 2	11,100
Debt Instrument [Line Items]
Capital leased assets	37,274	$ 38,350
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 56,079	55,619
Financing obligation, purchase option period	3 years
Buildings
Debt Instrument [Line Items]
Capital leased assets	$ 36,608	36,603
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 36,608	$ 36,603	$ 19,900	$ 17,100
Financing Lease Obligation
Debt Instrument [Line Items]
Capital leased assets			$ 11,100	$ 11,800

Commitments and Contingencies - Operating Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	$ 3,659
2019	2,630
2020	2,235
2021	2,187
2022	1,887
Thereafter	6,246
Total minimum lease payments	18,844
Capital Leases
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	66
2019	0
2020	0
2021	0
2022	0
Thereafter	0
Total minimum lease payments	66
Less: Amount representing interest	(2)
Present value of capital lease and financing obligations	64
Financing Obligations
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018	2,792
2019	2,792
2020	2,792
2021	2,792
2022	2,564
Thereafter	25,650
Total minimum lease payments	39,382
Less: Amount representing interest	(19,853)
Present value of capital lease and financing obligations	$ 19,529

Commitments and Contingencies - Government Grants (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) agreement employee	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Gain Contingencies [Line Items]
Government training reimbursement number of agreements \| agreement	5
Government training reimbursement number of employees \| employee	410
Proceeds from government grants, training reimbursement	$ 52	$ 83	$ 0
Gain (loss) on government grant reimbursement	1,578	1,141	744
Deferred government grant obligation, current	217	1,022
Other Operating Income (Expense)
Gain Contingencies [Line Items]
Gain (loss) on government grant reimbursement	1,600	1,000	$ 744
Training Reimbursement
Gain Contingencies [Line Items]
Deferred government grant obligation	261	1,800
Deferred government grant obligation, current	$ 217	$ 1,000

Commitments and Contingencies - Forgivable Grant (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2015 USD ($) job	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Feb. 01, 2011 USD ($) job
Debt Instrument [Line Items]
Repayment of government grant			$ 0	$ 0	$ 101,000
Other Commitments [Line Items]
Recognition of IEDA government grant			0	0	$ 1,638,000
Forgivable Grant
Other Commitments [Line Items]
Recognition of IEDA government grant		$ 2,200,000
Deferred government grant obligation			$ 0	$ 0
Forgivable Grant \| Operating Expenses
Other Commitments [Line Items]
Recognition of IEDA government grant		608,000
Forgivable Grant \| Other Operating Income (Expense)
Other Commitments [Line Items]
Recognition of IEDA government grant		$ 1,600,000
Forgivable Grant \| February 2011, 6% IDED Forgivable Grant
Debt Instrument [Line Items]
Debt face amount						$ 2,300,000
Number of jobs failed to meet minimum wage requirements \| job	10
Number of jobs required to create and retain for a specific period of time \| job						251
Repayment of government grant	$ 88,000

Commitments and Contingencies - Other Purchase Commitments (Details) - Cloud infrastructure services $ in Millions	1 Months Ended
	Nov. 30, 2017 USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Other purchase commitments, term of commitment	2 years
Other purchase commitments, payment in 2018	$ 4.1
Other purchase commitments, payment in 2019	$ 4.8

Debt - Other Long-Term Debt (Details) - Line of Credit - Silicon Valley Bank - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Aug. 31, 2014
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity				$ 15,000,000.0
Line of credit facility interest rate at period end	4.50%
Interest expense	$ 0	$ 0	$ 0
Line of credit outstanding	0	$ 0
Minimum
Debt Instrument [Line Items]
Line of credit asset restrictions on cash	$ 5,000,000.0

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Stockholders' Equity (Deficit) (Details)	12 Months Ended
Stockholders' Equity (Deficit) (Details)	Dec. 31, 2017 class vote
Class of Stock [Line Items]
Number of classes of common stock \| class	2
Class A Common Stock
Class of Stock [Line Items]
Common stock votes per share	1
Class B Common Stock
Class of Stock [Line Items]
Common stock votes per share	10
Rate of conversion	1

Stock-Based Compensation - Narrative (Details) - USD ($)		1 Months Ended	7 Months Ended
	Jun. 13, 2017	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP employee contributions			$ 1,419,000	$ 0
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP employee contributions			$ 1,400,000
Class A Common Stock \| Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant			5,000,000
Purchase price of common stock, percentage of fair market value	85.00%
Maximum stock purchase value, per employee			$ 12,500
Stock purchase offering period			6 months
Shares purchased during period			0
Shares distributed during period			0
Class A Common Stock \| 2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized		3,900,000
Number of shares available for grant			1,999,415

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 19,476	$ 14,247	$ 11,000
Subscription and support
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	738	493	363
Professional services
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	465	411	349
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	2,224	2,365	1,924
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	2,983	2,075	1,727
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 13,066	$ 8,903	$ 6,637

Stock-Based Compensation - Assumptions (Details)	12 Months Ended
Stock-Based Compensation - Assumptions (Details)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)			6 years 1 month 6 days
Risk-free interest rate, min	1.50%	1.20%	1.40%
Risk-free interest rate, max	2.20%	2.10%	1.90%
Expected volatility, min	23.70%	43.00%	42.40%
Expected volatility, max	43.80%	45.30%	47.10%
Employee stock option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	2 months 12 days	6 years
Employee stock option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	6 months
Risk-free interest rate	1.20%
Expected volatility	28.50%

Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Options (in shares):
Outstanding beginning of the period (in shares)	7,532,455
Granted (in shares)	2,111,253
Forfeited (in shares)	(339,111)
Exercised (in shares)	(1,158,820)
Outstanding end of the period (in shares)	8,145,777	7,532,455
Exercisable at end of the period (in shares)	4,607,812
Weighted-Average Exercise Price (in dollars per share):
Outstanding beginning of the period, weighted-average exercise price (in dollars per share)	$ 12.22
Granted, weighted-average exercise price (in dollars per share)	16.10
Forfeited, weighted-average exercise price (in dollars per share)	14.93
Exercised, weighted-average exercise price (in dollars per share)	10.77
Outstanding end of the period, weighted-average exercise price (in dollars per share)	13.33	$ 12.22
Exercisable at the end of the period, weighted-average exercise price (in dollars per share)	$ 11.49
Outstanding, weighted-average remaining contractual term (years)	7 years	7 years 2 months 12 days
Exercisable, weighted-average remaining contractual term (years)	5 years 8 months 12 days
Outstanding, aggregate intrinsic value	$ 65,913	$ 19,988
Exercisable, aggregate intrinsic value	45,653
Options Additional Information:
Options exercised intrinsic value	$ 9,800	$ 3,900	$ 8,400
Options grants in period, weighted average grant date fair value (in dollars per share)	$ 6.79	$ 6.79	$ 6.53
Options vested in period fair value	$ 10,200	$ 9,300	$ 8,700
Options unrecognized compensation expense	$ 19,700
Employee stock option
Options Additional Information:
Unrecognized compensation expense, period for recognition	2 years 6 months
Class A Common Stock \| Employee stock option
Options Additional Information:
Expiration period	10 years
Class A Common Stock \| Minimum \| Employee stock option
Options Additional Information:
Award vesting period	3 years
Class A Common Stock \| Maximum \| Employee stock option
Options Additional Information:
Award vesting period	4 years

Stock-Based Compensation - Restricted Stock Awards (Details) - Restricted Stock Awards - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period, fair value	$ 2,700	$ 3,300	$ 750
Number of Shares (in shares):
Unvested at beginning of period (in shares)	353,335
Granted (in shares)	0
Forfeited (in shares)	0
Vested (in shares)	(190,003)
Unvested at end of period (in shares)	163,332	353,335
Weighted-Average Grant Date Fair Value (in dollars per share)
Unvested at beginning of period, weighted-average grant date fair value (in dollars per share)	$ 13.40
Grants in period, weighted-average grant date fair value (in dollars per share)	0
Forfeited, weighted-average grant date fair value (in dollars per share)	0
Vested, weight-average grant date fair value (in dollars per share)	13.40
Unvested at end of period, weighted-average grant date fair value (in dollars per share)	$ 13.40	$ 13.40
Unrecognized compensation expense	$ 200
Unrecognized compensation expense, period for recognition	1 month 6 days
Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Non-employee Members, Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year

Stock-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period, fair value	$ 3,600,000	$ 0	$ 0
Number of Shares (in shares):
Unvested at beginning of period (in shares)	381,952
Granted (in shares)	413,792
Forfeited (in shares)	0
Vested (in shares)	(221,672)
Unvested at end of period (in shares)	574,072	381,952
Weighted-Average Grant Date Fair Value (in dollars per share)
Unvested at beginning of period, weighted-average grant date fair value (in dollars per share)	$ 15.11
Grants in period, weighted-average grant date fair value (in dollars per share)	13.95
Forfeited, weighted-average grant date fair value (in dollars per share)	0
Vested, weight-average grant date fair value (in dollars per share)	14.48
Unvested at end of period, weighted-average grant date fair value (in dollars per share)	$ 14.51	$ 15.11
Number of vested shares recipients elected to defer settlement (in shares)	191,485
Unrecognized compensation expense	$ 5,000,000.0
Unrecognized compensation expense, period for recognition	1 year 7 months 6 days
Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Non-employee Members, Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year

Stock-Based Compensation - Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 27
Unrecognized compensation expense, period for recognition	10 days

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning of the period	$ (3,125)	$ 25,719	$ 55,819
Other comprehensive income (loss)	(219)	50	94
End of the period	(16,934)	(3,125)	25,719
Accumulated translation adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning of the period	298	280	147
Other comprehensive income (loss)	(159)	18	133
End of the period	139	298	280
Accumulated unrealized holding gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning of the period	(7)	(39)	0
Other comprehensive income (loss)	(60)	32	(39)
End of the period	(67)	(7)	(39)
Accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning of the period	291	241	147
Other comprehensive income (loss)	(219)	50	94
End of the period	$ 72	$ 291	$ 241

Segments (Details) - segment	12 Months Ended
Segments (Details) - segment	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1
Geographic Concentration Risk \| Revenue \| United States
Concentration Risk [Line Items]
Concentration risk percentage	92.10%	93.80%	94.30%

Income Taxes - Income Before Income Tax, Domestic and Foreign (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
United States									$ (44,246)	$ (43,952)	$ (42,788)
Foreign									(119)	(1)	(618)
Loss before provision (benefit) for income taxes	$ (14,327)	$ (14,048)	$ (10,163)	$ (5,827)	$ (7,515)	$ (12,899)	$ (11,513)	$ (12,026)	$ (44,365)	$ (43,953)	$ (43,406)

Income Taxes - Components of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
State									$ 42	$ 12	$ 69
Foreign									19	44	0
Total Current									61	56	69
Deferred
Federal									0	(32)	(76)
Total Deferred									0	(32)	(76)
Total income tax provision	$ (6)	$ 25	$ 33	$ 9	$ 1	$ (8)	$ 12	$ 19	$ 61	$ 24	$ (7)

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal statutory rate										35.00%	35.00%	35.00%
Effect of:
Tax benefit at federal statutory rate										$ (15,528)	$ (15,384)	$ (15,192)
State taxes, net of federal benefit										(1,802)	(1,377)	(1,833)
Revaluation of deferred tax items due to tax rate change (federal and state)										22,880	0	0
Revaluation of deferred tax asset for current year net operating loss due to tax rate change										4,134	0	0
Permanent differences including section 162(m) limitations, stock compensation, gain on foreign restructuring, and meals & entertainment										5,141	1,292	636
Tax benefit of federal R&D credit										(2,366)	(1,781)	(1,270)
Recognition of excess tax benefits related to share-based payments										(3,606)	0	0
Valuation allowance										(8,586)	17,013	17,697
Other										(206)	261	(45)
Total income tax provision	$ (6)	$ 25	$ 33	$ 9	$ 1	$ (8)	$ 12	$ 19		$ 61	$ 24	$ (7)
Taxable gain for restructuring of foreign operations									$ 13,900

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Property and equipment	$ 15	$ 12
Accruals and reserves	199	1,104
Deferred rent	931	1,565
Compensation and benefits	11,973	16,048
Deferred revenue	4,762	3,255
Net operating loss and credits	41,108	45,625
Other	167	180
Total deferred tax assets	59,155	67,789
Valuation allowance	(58,639)	(67,225)
Total deferred tax assets	516	564
Deferred tax liabilities:
Property and equipment	(440)	(403)
Other deferred tax liabilities	(76)	(161)
Deferred tax liabilities	(516)	(564)
Total	0	$ 0
Decrease in deferred tax asset, net due to Tax Cuts and Jobs Act of 2017	22,900
Decrease in valuation allowance due to Tax Cuts and Jobs Act of 2017	$ 22,900

Income Taxes - Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 133,800
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	101,200
Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 480

Income Taxes - Tax Credit Carryforwards (Details) $ in Millions	Dec. 31, 2017 USD ($)
Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 6.0
State
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 1.3

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits-beginning of period	$ 168	$ 0
Additions for tax positions related to prior year	0	168
Reductions for tax positions related to prior year	0	0
Foreign currency adjustments	23	0
Additions for tax positions related to current year	0	0
Unrecognized tax benefits-end of period	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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Net loss	$ (14,321)	$ (14,073)	$ (10,196)	$ (5,836)	$ (7,516)	$ (12,891)	$ (11,525)	$ (12,045)	$ (44,426)	$ (43,977)	$ (43,399)
Weighted average common shares outstanding - basic and diluted (in shares)	42,108,764	41,815,139	41,429,691	41,108,611	40,872,772	40,762,960	40,593,908	40,451,668	41,618,838	40,671,133	39,852,624
Basic and diluted net loss per share (in dollars per share)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (0.18)	$ (0.32)	$ (0.28)	$ (0.30)	$ (1.07)	$ (1.08)	$ (1.09)
Class A Common Stock
Class of Stock [Line Items]
Net loss									$ (33,016)	$ (31,644)	$ (30,075)
Weighted average common shares outstanding - basic and diluted (in shares)									30,929,899	29,265,605	27,617,350
Basic and diluted net loss per share (in dollars per share)									$ (1.07)	$ (1.08)	$ (1.09)
Class B Common Stock
Class of Stock [Line Items]
Net loss									$ (11,410)	$ (12,333)	$ (13,324)
Weighted average common shares outstanding - basic and diluted (in shares)									10,688,939	11,405,528	12,235,274
Basic and diluted net loss per share (in dollars per share)									$ (1.07)	$ (1.08)	$ (1.09)

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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)	8,145,777	7,532,455	6,969,133
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)	163,332	353,335	600,025
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)	85,509	0	0

Unaudited Quarterly Results of Operations - Schedule of Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue
Subscription and support	$ 45,549	$ 43,214	$ 40,980	$ 39,540	$ 38,329	$ 36,237	$ 34,969	$ 33,585	$ 169,283	$ 143,120	$ 116,288
Professional services	8,957	8,854	8,411	12,364	8,045	8,473	8,042	10,966	38,586	35,526	28,984
Total revenue	54,506	52,068	49,391	51,904	46,374	44,710	43,011	44,551	207,869	178,646	145,272
Cost of revenue
Subscription and support	8,779	8,472	7,758	7,637	7,244	6,694	7,039	6,918	32,646	27,895	22,559
Professional services	7,310	7,180	6,528	6,581	5,964	6,040	5,538	6,188	27,599	23,730	17,645
Total cost of revenue	16,089	15,652	14,286	14,218	13,208	12,734	12,577	13,106	60,245	51,625	40,204
Gross profit	38,417	36,416	35,105	37,686	33,166	31,976	30,434	31,445	147,624	127,021	105,068
Operating expenses
Research and development	18,870	17,527	16,239	15,536	14,533	14,342	14,047	14,516	68,172	57,438	50,466
Sales and marketing	21,949	23,712	19,787	18,713	18,196	22,354	19,828	20,088	84,161	80,466	69,569
General and administrative	12,271	8,959	8,943	9,421	7,845	8,015	7,882	8,953	39,594	32,695	28,716
Total operating expenses	53,090	50,198	44,969	43,670	40,574	44,711	41,757	43,557	191,927	170,599	148,751
Loss from operations	(14,673)	(13,782)	(9,864)	(5,984)	(7,408)	(12,735)	(11,323)	(12,112)	(44,303)	(43,578)	(43,683)
Interest expense	(451)	(464)	(475)	(455)	(455)	(462)	(468)	(490)	(1,845)	(1,875)	(2,025)
Other income, net	797	198	176	612	348	298	278	576	1,783	1,500	2,302
Loss before provision (benefit) for income taxes	(14,327)	(14,048)	(10,163)	(5,827)	(7,515)	(12,899)	(11,513)	(12,026)	(44,365)	(43,953)	(43,406)
(Benefit) provision for income taxes	(6)	25	33	9	1	(8)	12	19	61	24	(7)
Net loss	$ (14,321)	$ (14,073)	$ (10,196)	$ (5,836)	$ (7,516)	$ (12,891)	$ (11,525)	$ (12,045)	$ (44,426)	$ (43,977)	$ (43,399)
Net loss per common share:
Basic and diluted (in dollars per share)	$ (0.34)	$ (0.34)	$ (0.25)	$ (0.14)	$ (0.18)	$ (0.32)	$ (0.28)	$ (0.30)	$ (1.07)	$ (1.08)	$ (1.09)
Weighted average common shares outstanding - basic and diluted (in shares)	42,108,764	41,815,139	41,429,691	41,108,611	40,872,772	40,762,960	40,593,908	40,451,668	41,618,838	40,671,133	39,852,624
General and administrative
Effect of Fourth Quarter Events [Line Items]
Expense due to accelerated vesting of equity awards	$ 1,900