Forescout (FSCT) 10-Q 8 Dec 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Dec. 05, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	FORESCOUT TECHNOLOGIES, INC
Entity Central Index Key	1,145,057
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		37,906,920

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 72,344	$ 79,665
Accounts receivable	49,080	44,694
Inventory	132	890
Prepaid expenses and other current assets	8,431	8,592
Total current assets	129,987	133,841
Property and equipment, net	23,264	24,536
Severance pay deposits	1,987	1,704
Restricted cash	4,137	4,011
Other assets	4,951	3,334
Total assets	164,326	167,426
Current liabilities:
Accounts payable	1,889	5,210
Accrued compensation	21,106	17,286
Accrued expenses	11,002	12,903
Customer deposits	6,506	718
Deferred revenue	91,216	68,844
Notes payable	7,224	7,163
Total current liabilities	138,943	112,124
Warrant liabilities	5,216	4,874
Deferred revenue - non-current	56,712	40,070
Notes payable - non-current	17,398	22,824
Accrued severance pay liability	2,524	2,033
Other liabilities	9,340	10,244
Total liabilities	230,133	192,169
Commitments and Contingencies
Redeemable convertible preferred stock	283,854	283,854
Stockholders' deficit:
Common stock, $0.001 par value; 50,000,000 shares authorized; 6,175,126 and 5,854,147 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	6	6
Additional paid-in capital	98,555	84,792
Accumulated deficit	(448,222)	(393,395)
Total stockholders’ deficit	(349,661)	(308,597)
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	$ 164,326	$ 167,426

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (shares)	50,000,000	50,000,000
Common stock, shares issued (shares)	6,175,126	5,854,147
Common stock, shares outstanding (shares)	6,175,126	5,854,147

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Product	$ 39,192	$ 30,799	$ 83,889	$ 68,861
Maintenance and professional services	25,164	17,941	71,026	48,550
Total revenue	64,356	48,740	154,915	117,411
Cost of revenue:
Product	7,201	6,563	17,117	13,754
Maintenance and professional services	8,688	6,945	25,662	19,304
Total cost of revenue	15,889	13,508	42,779	33,058
Total gross profit	48,467	35,232	112,136	84,353
Operating expenses:
Research and development	10,985	8,509	32,634	22,352
Sales and marketing	34,957	35,759	104,515	94,316
General and administrative	9,148	7,967	27,265	23,081
Total operating expenses	55,090	52,235	164,414	139,749
Loss from operations	(6,623)	(17,003)	(52,278)	(55,396)
Interest expense	(290)	(702)	(953)	(2,072)
Other income (expense), net	160	(226)	(66)	(354)
Change in fair value of warrant liabilities	0	(224)	(342)	379
Loss before income taxes	(6,753)	(18,155)	(53,639)	(57,443)
Income tax provision	412	157	1,221	517
Net loss and comprehensive loss	$ (7,165)	$ (18,312)	$ (54,860)	$ (57,960)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (1.17)	$ (3.18)	$ (9.09)	$ (10.46)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (shares)	6,139,876	5,749,930	6,032,427	5,539,012

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net loss	$ (54,860)	$ (57,960)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Stock-based compensation	12,060	12,862
Depreciation	4,264	2,279
Loss on disposal of property and equipment	187	19
Amortization of discount on debt	259	554
Change in fair value of warrant liabilities	342	(379)
Changes in operating assets and liabilities
Accounts receivable	(4,386)	(2,562)
Inventory	835	125
Prepaid expenses and other current assets	177	(4,516)
Other assets	(131)	(1,723)
Accounts payable	(3,319)	(1,630)
Accrued compensation	3,820	4,725
Accrued expenses	(567)	1,855
Customer deposits	5,788	(709)
Deferred revenue	39,014	10,085
Severance pay, net	208	151
Other liabilities	(128)	6,429
Net cash provided by (used in) operating activities	3,563	(30,395)
Cash flows from investing activities
Purchases of property and equipment	(3,386)	(19,959)
Purchases of short-term investments	0	(23,983)
Proceeds from maturities of short-term investments	0	12,000
Proceeds from sales of short-term investments	0	11,979
Change in restricted cash	(126)	(199)
Net cash used in investing activities	(3,512)	(20,162)
Cash flows from financing activities
Repayments of notes payable	(5,624)	0
Net proceeds from issuance of redeemable convertible preferred stock	0	2,399
Proceeds from exercise of stock options	960	907
Payments of deferred offering costs	(2,708)	0
Net cash (used in) provided by financing activities	(7,372)	3,306
Net change in cash and cash equivalents for period	(7,321)	(47,251)
Cash and cash equivalents at beginning of period	79,665	126,846
Cash and cash equivalents at end of period	72,344	79,595
Noncash disclosure of investing and financing activities:
Change in liability for early exercise of stock options, net of vested portion	776	812
Leasehold improvements paid by lessor	0	338
Purchases of property and equipment recorded in accounts payable and accrued expenses	144	1,037
Deferred offering costs included in accrued expenses	$ 501	$ 0

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Summary of Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies Company and Background ForeScout Technologies, Inc. (the “Company”) was incorporated in the State of Delaware and commenced operations in April 2000. The Company provides an agentless approach to network security to protect organizations against the emerging threats that exploit billions of Internet of Things (“IoT”) devices connected to an organization’s networks. The Company offers its solution across three products: (i) ForeScout CounterACT ® , (ii) ForeScout CounterACT Enterprise Manager and (iii) ForeScout Extended Modules. The Company’s CounterACT product provides visibility and policy-based mitigation of security issues. The Company’s CounterACT Enterprise Manager is a centralized security management solution for global control of all CounterACT products. The Company’s Extended Modules expand CounterACT’s see and control capabilities by sharing contextual device data with third-party systems and by automating policy enforcement across those disparate systems. The Company sells its products, maintenance and professional services to end-customers through distributors and resellers, who are supported by the Company’s sales and marketing organization, and to a lesser extent directly to end-customers. Initial Public Offering On October 31, 2017 , the Company closed its initial public offering (“IPO”), in which it issued and sold 6,072,000 shares of common stock inclusive of the underwriters’ option to purchase additional shares that was exercised in full. The price per share to the public was $22.00 . The Company received aggregate proceeds of $124.2 million from the IPO, net of underwriters’ discounts and commissions, and before deducting offering costs of approximately $3.5 million . Upon the closing of the IPO, all shares of the Company's outstanding redeemable convertible preferred stock automatically converted into 25,370,616 shares of common stock. Total outstanding shares after closing of the IPO and after conversion of all shares of the Company's outstanding redeemable convertible preferred stock was 37,861,342 at October 31, 2017 . Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information using accounting policies that are consistent with those used in the preparation of the Company’s audited consolidated financial statements for the year ended December 31, 2016 . Our condensed consolidated financial statements include the results of ForeScout Technologies, Inc. and its wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated financial statements are unaudited and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, necessary for the fair presentation of our quarterly results. The condensed consolidated balance sheet as of December 31, 2016 was derived from the audited consolidated financial statements at that date but does not include all the disclosures required by GAAP for the annual financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2016 , which are included in the Company’s prospectus related to the Company’s initial public offering, filed October 27, 2017 (the “Prospectus”), pursuant to Rule 424 (b) under the Securities Act of 1933, as amended (the “Securities Act”) with the Securities and Exchange Commission (the “SEC”). The preparation of interim condensed consolidated financial statements in conformity with GAAP requires management to make use of estimates and assumptions that affect the reported amounts in the condensed consolidated financial statements and accompanying notes. These estimates form the basis of judgments made about carrying values of assets and liabilities, which are not readily apparent from other sources. The areas where management has made estimates requiring judgment include, but are not limited to, the allocation of revenue in multiple element arrangements, sales return reserve, accruals, stock-based compensation including the fair value of common stock, redeemable convertible preferred stock warrant liabilities, and provision for income taxes including related reserves. Actual results could differ materially from those estimates. Reverse Stock Split On October 16, 2017, the Company amended its amended and restated certificate of incorporation to effect a two-to-one reverse stock split of its common stock and convertible preferred stock (the “Reverse Stock Split”). Upon the filing of the amended and restated certificate of incorporation in the state of Delaware, (i) each two shares of outstanding convertible preferred stock and each two shares of outstanding common stock were exchanged and combined into one share of convertible preferred stock and one share of common stock, respectively; (ii) the number of shares of common stock issuable under each outstanding option to purchase common stock and issuable upon vesting under each restricted stock unit was proportionately reduced on a two-to-one basis; (iii) the exercise price of each outstanding option to purchase common stock was proportionately increased on a two-to-one basis; (iv) the number of shares of convertible preferred stock issuable under outstanding warrants was proportionally reduced on a two-to-one basis and the exercise price of such warrants was proportionally increased on a two-to-one basis; and (v) corresponding adjustments in the per share conversion prices, dividend rates and liquidation preferences of the convertible preferred stock were made on a two-to-one basis. Accordingly, all share and per share information presented in the condensed consolidated financial statements herein, and notes thereto, have been retroactively adjusted to reflect the Reverse Stock Split. Summary of Significant Accounting Policies There have been no material changes to our significant accounting policies as compared to those described in the Prospectus. Inventory Inventory primarily consists of finished goods hardware appliances and is stated at the lower of cost or market determined using the specific identification method. Inventory that is obsolete or in excess of forecasted demand is written down to its estimated realizable value. Inventory write-downs, once established, are not reversed as they establish a new cost basis for the inventory. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09 (Topic 606), Revenue from Contracts with Customers (“ASU 2014-09”), related to revenue from contracts with customers, which, along with amendments issued in 2015 and 2016, will supersede nearly all current GAAP guidance on this topic and eliminate industry-specific guidance. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (“full retrospective method,”) or retrospectively with the cumulative effect of applying the guidance recognized in retained earnings as of the date of adoption (“modified retrospective method”). The Company currently anticipates adopting the standard using the full retrospective method to restate each prior reporting period presented. The Company’s ability to adopt the full retrospective method is dependent upon system readiness and the Company’s ability to gather sufficient data to timely assess the impact on prior period financial statements. The Company plans to adopt the new standard effective January 1, 2018. The Company is currently evaluating the impacts of the new standard on its accounting policies, processes, and system requirements and has assigned internal resources, in addition to the engagement of third party service providers, to assist in the evaluation. While the Company is continuing to assess all potential impacts of this standard, the Company currently believes that the most significant impacts relate to the accounting for Software Products, which include Virtual Appliances, Enterprise License Software sold without hardware, and Extended Modules as software deliverables, and contract acquisition costs. For Software Products, sold prior to January 1, 2016, vendor-specific objective evidence of fair value (“VSOE”) for support and maintenance on Software Products was not established, and the Company recorded all Software Product related revenue ratably over the contractually committed support and maintenance period. Professional services sold in conjunction with such Software Products were also recognized ratably over the contractually committed support and maintenance period. Under the new standard the requirement to have VSOE for undelivered elements is eliminated and an entity may be required to recognize Software Product revenue at the time of delivery, and any related professional services revenue as services are provided to the customers. For contract acquisition costs, the new standard requires the capitalization of such costs, which is primarily sales commissions, and amortization of these costs over the contract period or estimated customer life, which will result in the recognition of a deferred charge on the Company’s balance sheets. The Company currently expenses all sales commissions and other incremental costs to acquire contracts as they are incurred. Additionally, the Company expects revenue allocated from future deliverables (primarily support and maintenance) to Physical Appliances, which include CounterACT and Enterprise Manager hardware appliances embedded with the Company’s software, to be recognized upon delivery under the new guidance when the standalone selling price is different from the contract price. Such differences are currently recognized over the contractual support and maintenance period. While the Company continues to assess the potential impacts of the new standard, including the areas described above, and anticipates that this standard could have a material impact on its consolidated financial statements, it does not know or cannot reasonably estimate quantitative information related to the impact of the new standard on the financial statements at this time. In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases. The new guidance requires lessees to recognize right-of-use assets and lease liabilities for those leases classified as operating leases under previous U.S. GAAP. The standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2018, and will be applied on a modified retrospective basis, with the option to elect certain practical expedients. Early adoption is permitted. The Company is currently evaluating the timing and impact of the adoption of this standard on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09 (Topic 718), Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). This standard is intended to simplify several areas of accounting for stock-based compensation arrangements, including the income tax impact, classification on the statement of cash flows and forfeitures. ASU 2016-09 is effective for annual and interim periods within those fiscal years, beginning after December 15, 2016. The Company adopted this standard in the first quarter of 2017 and elected to account for forfeitures as they occur, rather than estimate expected forfeitures. The change has been applied on a modified retrospective basis that resulted in a $34,000 cumulative-effect adjustment to accumulated deficit as of January 1, 2017, the date of adoption. The adoption of this guidance also requires that excess tax benefits and tax deficiencies be recorded in the statement of operations as opposed to additional paid-in capital when the awards vest or are settled, and has been applied on a prospective basis. As a result, deferred tax assets increased by $2.3 million as of January 1, 2017, offset by valuation allowance, due to tax deductions related to equity compensation greater than compensation recognized for financial reporting. In November 2016, the FASB issued ASU No. 2016-18 (Topic 230), Statement of Cash Flows: Restricted Cash . The new standard requires an entity to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows, and an entity will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. The standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2017, and should be applied retrospectively. Early adoption is permitted. The Company is currently evaluating the timing and impact of the adoption of this standard on its consolidated financial statements. In May 2017, the FASB issued ASU 2017-09 (Topic 718), Compensation-Stock Compensation: Scope of Modification Accounting. This standard provides guidance on when to account for a change to the terms or conditions of a share-based payment award as a modification. Under this new standard, 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. This standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The Company does not expect the adoption of this standard to have a material impact on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Financial assets and liabilities are recorded at fair value on the consolidated balance sheets and are categorized based upon the level of judgment associated with inputs used to measure their fair value. Fair value reflects the price that would be received on the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining fair value measurements, the Company considers the principal or most advantageous market and also market-based risk. The accounting guidance for fair value measurements requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The accounting guidance also establishes a fair value hierarchy based on the independence of the source and objective evidence of the inputs used. There are three fair value hierarchies based upon the level of inputs that are significant to fair value measurement: • Level 1 —Observable inputs that reflect quoted prices in active markets for identical assets or liabilities. • Level 2 —Observable inputs that reflect quoted prices for identical assets and liabilities in markets that are not active, quoted prices for similar assets or liabilities in active markets, inputs other than quoted prices that are observable for the assets or liabilities, or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3 —Inputs that are generally unobservable and are supported by little or no market activity, and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability. There have been no transfers between fair value measurement levels during the periods presented. The following table presents the fair value of the Company’s financial assets and liabilities according to the fair value hierarchy (in thousands): September 30, 2017 December 31, 2016 Financial Assets Level 1 Level 3 Level 1 Level 3 Cash and cash equivalents: Cash $ 34,986 $ — $ 42,499 $ — Money market accounts 37,358 — 37,166 — Total cash and cash equivalents 72,344 — 79,665 — Restricted cash (current and non-current) 4,339 — 4,212 — Total financial assets $ 76,683 $ — $ 83,877 $ — Financial Liabilities Warrant liabilities $ — $ 5,216 $ — $ 4,874 The Company’s Level 3 financial liabilities consist of warrant liabilities on redeemable convertible preferred stock and common stock. The following table presents the activity for the warrant liabilities (in thousands): Level 3 Balance as of December 31, 2016 $ 4,874 Change in fair value of warrant liabilities 342 Balance as of September 30, 2017 $ 5,216

Equity Award Plans

Equity Award Plans	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Award Plans	Equity Award Plans Stock Option Activity The following table summarizes option activity under the 2000 Plan and related information (in thousands, except share, per share and contractual life amounts): Options Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2016 9,587,515 $ 10.13 8.0 $ 61,865 Options granted 458,099 $ 18.46 Options exercised (222,447 ) $ 4.32 Options forfeited (410,026 ) $ 14.31 Balance—September 30, 2017 9,413,141 $ 10.49 7.4 $ 87,637 Options vested and expected to vest—September 30, 2017 9,413,141 $ 10.49 7.4 $ 87,637 Options vested and exercisable—September 30, 2017 5,014,239 $ 8.34 6.8 $ 57,377 As of September 30, 2017 , total unrecognized compensation cost related to unvested options was $28.8 million , which was expected to be amortized on a straight-line basis over a weighted-average period of approximately 2.2 years . Restricted Stock Unit (“RSU”) Activity The following table summarizes RSU activity under the 2000 Plan and related information (in thousands, except share, per share and contractual life amounts): RSUs Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2016 1,898,623 $ 14.83 1.7 $ 30,720 RSUs granted 1,155,350 $ 19.25 RSUs forfeited (22,750 ) $ 20.18 Balance—September 30, 2017 3,031,223 $ 16.48 1.8 $ 59,958 RSUs vested and expected to vest—September 30, 2017 3,029,970 $ 17.22 1.8 $ 59,933 As of September 30, 2017 , total unrecognized compensation cost related to unvested RSUs was $2.5 million , excluding RSUs with a performance condition, and are expected to be amortized on a straight-line basis over a weighted-average period of approximately 1.4 years . Stock-Based Compensation Stock-based compensation expense for both employees and non-employees included in the accompanying condensed consolidated statements of operations and comprehensive loss is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Cost of revenue: Product $ 19 $ 6 $ 60 $ 16 Maintenance and professional services 286 317 930 809 Research and development 630 613 2,043 1,645 Sales and marketing 1,602 1,543 4,868 6,469 General and administrative 1,372 1,339 4,159 3,923 Total $ 3,909 $ 3,818 $ 12,060 $ 12,862 As of September 30, 2017 , the Company had a total of 294,160 options outstanding to employees and non-employees, with exercise prices ranging from $0.43 to $1.47 , that will only vest upon the completion of an IPO or change in control. As of September 30, 2017 , the Company had a total of 2,420,273 restricted stock units outstanding with a performance condition dependent upon completion of an IPO or a change in control. If an IPO or a change in control had occurred as of September 30, 2017 , the Company would have recorded stock-based compensation expense of approximately $22.1 million and the unrecognized compensation cost related to these performance-based stock options and RSUs would have been $31.0 million to be amortized over a weighted-average period of approximately 1.9 years . Upon the closing of the IPO on October 31, 2017 , the Company recognized stock-based compensation expense of approximately $24.1 million related to the performance-based stock options and RSUs. In September 2017, the Company amended its Chief Executive Officer's (“CEO”) employment agreement to provide for accelerated vesting of all of the CEO’s equity awards upon his termination due to death or disability while executing his employment duties. As a result of this modification to the CEO’s vesting terms, the Company expects to record an incremental $7.6 million in stock-based compensation expense over the service period beginning in October 2017 following the completion of the Company's IPO. Determining the Fair Value of Stock Options The fair value of stock option awards is estimated using the Black-Scholes option-pricing model. The assumptions used to determine the grant date fair value of employee stock options for the periods presented are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Fair value of common stock $19.78 – $19.78 $18.18 – $19.56 $16.73 – $19.78 $15.78 – $19.56 Risk-free interest rate 1.9% – 2.0% 1.2% – 1.3% 1.9% – 2.1% 1.2% – 1.6% Expected term (in years) 6.0 – 6.1 6.1 – 6.2 6.0 – 6.1 6.0 – 8.1 Volatility 47% – 48% 50% – 51% 47% – 49% 47% – 51% Dividend yield —% —% —% —%

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company estimates its annual effective tax rate each quarter and specific events are discretely recognized as they occur under the provisions of ASC 740-270. For the three and nine months ended September 30, 2017 , the Company recorded a tax provision of $412,000 and $1.2 million , respectively, representing an effective tax rate of (6.1)% and (2.3)% , respectively. The Company’s effective tax rates for these periods were negative as it has maintained a valuation allowance on the U.S. losses. The key components of the income tax provision primarily consist of foreign income taxes, income tax reserves, and U.S. state minimum taxes. As compared to the same periods last year, the difference in the effective tax rate is primarily due to change in the uncertain tax positions as a result of a statutory income tax and withholding tax audit in one of our foreign subsidiaries. For the three and nine months ended September 30, 2016 , the Company recorded a tax provision of $157,000 and $517,000 , respectively, representing an effective tax rate of (0.9)% for each period. The Company’s effective tax rates for these periods were negative as it maintained a valuation allowance on the U.S. losses. The key components of the income tax provision primarily consisted of foreign income taxes, income tax reserves, and U.S. state minimum taxes.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Net loss per share of common stock is computed using the two-class method required for participating securities based on their participation rights. All series of redeemable convertible preferred stock are participating securities as the holders are entitled to participate in common stock dividends with common stock on an as-converted basis. The holders of the Company’s redeemable convertible preferred stock are also entitled to noncumulative dividends prior and in preference to common stock and do not have a contractual obligation to share in the losses of the Company. In accordance with the two-class method, earnings allocated to these participating securities, which include participation rights in undistributed earnings with common stock, are subtracted from net loss to determine net loss attributable to common stockholders. Basic net loss per share is computed by dividing net loss attributable to common stockholders by basic weighted-average shares outstanding during the period. All participating securities are excluded from basic weighted-average shares outstanding. In computing diluted net loss attributable to common stockholders, undistributed earnings are re-allocated to reflect the potential impact of dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing net loss attributable to common stockholders by diluted weighted-average shares outstanding, including potentially dilutive securities, unless anti-dilutive. The following table presents the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Net loss attributable to common stockholders $ (7,165 ) $ (18,312 ) $ (54,860 ) $ (57,960 ) Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted 6,139,876 5,749,930 6,032,427 5,539,012 Net loss per share attributable to common stockholders, basic and diluted $ (1.17 ) $ (3.18 ) $ (9.09 ) $ (10.46 ) The following securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because their inclusion would reduce the net loss per share. As of September 30, 2017 2016 Options to purchase common stock 9,413,141 9,403,045 Unvested early exercised common shares 231,423 364,800 Unvested restricted stock units 3,031,223 1,039,121 Warrants to purchase common stock 233,023 233,023 Redeemable convertible preferred stock 24,788,362 24,788,362 Warrants to purchase redeemable convertible preferred stock 292,862 292,862

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information The Company’s business is conducted globally. The Company’s chief operating decision maker, who is the CEO, reviews financial information presented on a consolidated basis accompanied by information regarding revenue by geographic region for purposes of allocating resources and evaluating financial performance. There is one business activity and there are no segment managers who are held accountable for operations, operating results, and plans for levels, components, or types of products or services below the consolidated unit level. Accordingly, the Company has a single reporting segment and operating unit structure. Revenue by geographic area is attributed based on the billing address of the customer and is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Revenue: Americas United States $ 50,348 $ 39,877 $ 119,409 $ 92,486 Other Americas 1,602 1,481 3,989 3,421 Total Americas 51,950 41,358 123,398 95,907 Europe, Middle East, and Africa (“EMEA”) 8,071 4,350 21,275 13,820 Asia Pacific and Japan (“APJ”) 4,335 3,032 10,242 7,684 Total revenue $ 64,356 $ 48,740 $ 154,915 $ 117,411 Long-lived assets, net by geographic area are attributed based on legal entity structure and are as follows (in thousands): As of September 30, 2017 December 31, 2016 Long-lived assets, net: United States $ 19,682 $ 21,141 Israel 3,034 3,051 Other 548 344 Total long-lived assets, net $ 23,264 $ 24,536

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 16, 2017, as an inducement for the holders of Series G redeemable preferred stock to convert their shares of Series G preferred stock into common stock immediately prior to the IPO, the Company amended and restated its amended and restated certificate of incorporation to adjust the conversion rate for the Series G redeemable preferred stock in the event the IPO price was less than $29.66 per share. On October 31, 2017, based on an IPO price of $22.00 per share, the Company issued 582,254 additional shares of common stock to the holders of shares of Series G redeemable preferred stock upon conversion of Series G redeemable preferred stock into shares of common stock immediately prior to the closing of the IPO. The stock issuance was accounted for as a stock dividend at the time of issuance. On October 16, 2017, the Company’s stockholders approved the Company’ s 2017 Equity Incentive Plan (the “2017 Plan”), and the Company’ s 2017 Employee Stock Purchase Plan (the “ESPP”). The 2017 Plan provides for the grant of incentive stock options, nonstatutory stock options, restricted stock, restricted stock units, stock appreciation rights, performance stock units, performance shares, and performance awards. A total of 3,800,000 shares of the Company’s common stock are reserved for future issuance pursuant to the 2017 Plan. In addition, shares subject to outstanding awards granted under the Company’s 2000 Plan (the “2000 Plan”), that are canceled, expire, or otherwise terminate without having been exercised in full and shares previously issued under the 2000 Plan that are forfeited to the Company, tendered to or withheld by the Company for the payment of an award’s exercise price or for tax withholding, or repurchased by the Company, may be added to the 2017 Plan (provided that the maximum number of shares that may be added to the Company’s 2017 Plan pursuant to the provision in this sentence is 12,500,000 shares). The number of shares available for future issuance under the Company’s 2017 Plan also includes automatic annual increases on the first day of the Company’s fiscal year beginning with 2018, equal to the least of: 3,800,000 shares; 5% of the outstanding shares of common stock as of the last day of the Company’s immediately preceding fiscal year; or such lower number of shares as determined by the administrator of the 2017 Plan. The ESPP allows eligible employees to purchase shares of the Company’s common stock through payroll deductions and is intended to qualify under Section 423 of the Internal Revenue Code. A total of 800,000 shares of the Company’s common stock are available for sale under the ESPP. The number of shares available for issuance under the Company’s ESPP will also include an automatic, annual increase on the first day of each fiscal year of the Company beginning in 2018, equal to the lesser of: 800,000 shares; 1% of the total number of shares of the Company’s common stock outstanding on the last day of the Company’s immediately preceding fiscal year; or such lower number of shares as determined by the administrator of the ESPP. The ESPP provides for consecutive, overlapping six month offering periods. The offering periods are scheduled to start on the first trading day on or after May 20 and November 20 of each year, except for the first offering period which began on October 26, 2017 and will end on the first trading day on or after May 20, 2018. Participants may purchase the Company’s common stock through payroll deductions, of up to a maximum of 15% of their eligible compensation. Participation will end automatically upon termination of employment with the Company. The purchase price of the shares will be 85% of the lower of the fair market value of the Company’s common stock on the first trading day of each offering period or on the exercise date. On October 24, 2017, Network Security Technologies, LLC, or NST, filed a lawsuit against the Company alleging patent infringement. NST is seeking compensatory damages and attorneys’ fees. The Company believes it has meritorious defenses and intends to vigorously defend the claims against the Company. This litigation is still in its early stages and the final outcome, including any estimated liability, if any, with respect to these claims, is uncertain. At present, the Company is unable to estimate a reasonably possible range of loss, if any, that may result from this matter. On October 27, 2017 and November 1, 2017, warrants to purchase the Company's common stock were exercised for a total 442,648 shares at exercise prices of $6.00 and $6.62 per share. In lieu of payment of the aggregate warrant price, the warrant holders elected a "cashless exercise", whereby a portion of the shares equal to the aggregate warrant price were withheld. The average fair market value at the time exercise was $25.73 , which resulted in 335,838 shares being issued by the Company.

Description of Business and S13

Description of Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information using accounting policies that are consistent with those used in the preparation of the Company’s audited consolidated financial statements for the year ended December 31, 2016 . Our condensed consolidated financial statements include the results of ForeScout Technologies, Inc. and its wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated financial statements are unaudited and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, necessary for the fair presentation of our quarterly results. The condensed consolidated balance sheet as of December 31, 2016 was derived from the audited consolidated financial statements at that date but does not include all the disclosures required by GAAP for the annual financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2016 , which are included in the Company’s prospectus related to the Company’s initial public offering, filed October 27, 2017 (the “Prospectus”), pursuant to Rule 424 (b) under the Securities Act of 1933, as amended (the “Securities Act”) with the Securities and Exchange Commission (the “SEC”). The preparation of interim condensed consolidated financial statements in conformity with GAAP requires management to make use of estimates and assumptions that affect the reported amounts in the condensed consolidated financial statements and accompanying notes. These estimates form the basis of judgments made about carrying values of assets and liabilities, which are not readily apparent from other sources. The areas where management has made estimates requiring judgment include, but are not limited to, the allocation of revenue in multiple element arrangements, sales return reserve, accruals, stock-based compensation including the fair value of common stock, redeemable convertible preferred stock warrant liabilities, and provision for income taxes including related reserves. Actual results could differ materially from those estimates.
Inventory	Inventory primarily consists of finished goods hardware appliances and is stated at the lower of cost or market determined using the specific identification method. Inventory that is obsolete or in excess of forecasted demand is written down to its estimated realizable value. Inventory write-downs, once established, are not reversed as they establish a new cost basis for the inventory.
Recent Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09 (Topic 606), Revenue from Contracts with Customers (“ASU 2014-09”), related to revenue from contracts with customers, which, along with amendments issued in 2015 and 2016, will supersede nearly all current GAAP guidance on this topic and eliminate industry-specific guidance. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (“full retrospective method,”) or retrospectively with the cumulative effect of applying the guidance recognized in retained earnings as of the date of adoption (“modified retrospective method”). The Company currently anticipates adopting the standard using the full retrospective method to restate each prior reporting period presented. The Company’s ability to adopt the full retrospective method is dependent upon system readiness and the Company’s ability to gather sufficient data to timely assess the impact on prior period financial statements. The Company plans to adopt the new standard effective January 1, 2018. The Company is currently evaluating the impacts of the new standard on its accounting policies, processes, and system requirements and has assigned internal resources, in addition to the engagement of third party service providers, to assist in the evaluation. While the Company is continuing to assess all potential impacts of this standard, the Company currently believes that the most significant impacts relate to the accounting for Software Products, which include Virtual Appliances, Enterprise License Software sold without hardware, and Extended Modules as software deliverables, and contract acquisition costs. For Software Products, sold prior to January 1, 2016, vendor-specific objective evidence of fair value (“VSOE”) for support and maintenance on Software Products was not established, and the Company recorded all Software Product related revenue ratably over the contractually committed support and maintenance period. Professional services sold in conjunction with such Software Products were also recognized ratably over the contractually committed support and maintenance period. Under the new standard the requirement to have VSOE for undelivered elements is eliminated and an entity may be required to recognize Software Product revenue at the time of delivery, and any related professional services revenue as services are provided to the customers. For contract acquisition costs, the new standard requires the capitalization of such costs, which is primarily sales commissions, and amortization of these costs over the contract period or estimated customer life, which will result in the recognition of a deferred charge on the Company’s balance sheets. The Company currently expenses all sales commissions and other incremental costs to acquire contracts as they are incurred. Additionally, the Company expects revenue allocated from future deliverables (primarily support and maintenance) to Physical Appliances, which include CounterACT and Enterprise Manager hardware appliances embedded with the Company’s software, to be recognized upon delivery under the new guidance when the standalone selling price is different from the contract price. Such differences are currently recognized over the contractual support and maintenance period. While the Company continues to assess the potential impacts of the new standard, including the areas described above, and anticipates that this standard could have a material impact on its consolidated financial statements, it does not know or cannot reasonably estimate quantitative information related to the impact of the new standard on the financial statements at this time. In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases. The new guidance requires lessees to recognize right-of-use assets and lease liabilities for those leases classified as operating leases under previous U.S. GAAP. The standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2018, and will be applied on a modified retrospective basis, with the option to elect certain practical expedients. Early adoption is permitted. The Company is currently evaluating the timing and impact of the adoption of this standard on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09 (Topic 718), Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). This standard is intended to simplify several areas of accounting for stock-based compensation arrangements, including the income tax impact, classification on the statement of cash flows and forfeitures. ASU 2016-09 is effective for annual and interim periods within those fiscal years, beginning after December 15, 2016. The Company adopted this standard in the first quarter of 2017 and elected to account for forfeitures as they occur, rather than estimate expected forfeitures. The change has been applied on a modified retrospective basis that resulted in a $34,000 cumulative-effect adjustment to accumulated deficit as of January 1, 2017, the date of adoption. The adoption of this guidance also requires that excess tax benefits and tax deficiencies be recorded in the statement of operations as opposed to additional paid-in capital when the awards vest or are settled, and has been applied on a prospective basis. As a result, deferred tax assets increased by $2.3 million as of January 1, 2017, offset by valuation allowance, due to tax deductions related to equity compensation greater than compensation recognized for financial reporting. In November 2016, the FASB issued ASU No. 2016-18 (Topic 230), Statement of Cash Flows: Restricted Cash . The new standard requires an entity to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows, and an entity will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. The standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2017, and should be applied retrospectively. Early adoption is permitted. The Company is currently evaluating the timing and impact of the adoption of this standard on its consolidated financial statements. In May 2017, the FASB issued ASU 2017-09 (Topic 718), Compensation-Stock Compensation: Scope of Modification Accounting. This standard provides guidance on when to account for a change to the terms or conditions of a share-based payment award as a modification. Under this new standard, 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. This standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The Company does not expect the adoption of this standard to have a material impact on its consolidated financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Financial Assets and Liabilities	The following table presents the fair value of the Company’s financial assets and liabilities according to the fair value hierarchy (in thousands): September 30, 2017 December 31, 2016 Financial Assets Level 1 Level 3 Level 1 Level 3 Cash and cash equivalents: Cash $ 34,986 $ — $ 42,499 $ — Money market accounts 37,358 — 37,166 — Total cash and cash equivalents 72,344 — 79,665 — Restricted cash (current and non-current) 4,339 — 4,212 — Total financial assets $ 76,683 $ — $ 83,877 $ — Financial Liabilities Warrant liabilities $ — $ 5,216 $ — $ 4,874
Schedule of Activity for Warrant Liabilities	The following table presents the activity for the warrant liabilities (in thousands): Level 3 Balance as of December 31, 2016 $ 4,874 Change in fair value of warrant liabilities 342 Balance as of September 30, 2017 $ 5,216

Equity Award Plans (Tables)

Equity Award Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Option Activity under the Plan	The following table summarizes option activity under the 2000 Plan and related information (in thousands, except share, per share and contractual life amounts): Options Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2016 9,587,515 $ 10.13 8.0 $ 61,865 Options granted 458,099 $ 18.46 Options exercised (222,447 ) $ 4.32 Options forfeited (410,026 ) $ 14.31 Balance—September 30, 2017 9,413,141 $ 10.49 7.4 $ 87,637 Options vested and expected to vest—September 30, 2017 9,413,141 $ 10.49 7.4 $ 87,637 Options vested and exercisable—September 30, 2017 5,014,239 $ 8.34 6.8 $ 57,377
Schedule of RSU Activity under the Plan	The following table summarizes RSU activity under the 2000 Plan and related information (in thousands, except share, per share and contractual life amounts): RSUs Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2016 1,898,623 $ 14.83 1.7 $ 30,720 RSUs granted 1,155,350 $ 19.25 RSUs forfeited (22,750 ) $ 20.18 Balance—September 30, 2017 3,031,223 $ 16.48 1.8 $ 59,958 RSUs vested and expected to vest—September 30, 2017 3,029,970 $ 17.22 1.8 $ 59,933
Schedule of Stock-based Compensation Expense for Employees and Non-Employees	Stock-based compensation expense for both employees and non-employees included in the accompanying condensed consolidated statements of operations and comprehensive loss is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Cost of revenue: Product $ 19 $ 6 $ 60 $ 16 Maintenance and professional services 286 317 930 809 Research and development 630 613 2,043 1,645 Sales and marketing 1,602 1,543 4,868 6,469 General and administrative 1,372 1,339 4,159 3,923 Total $ 3,909 $ 3,818 $ 12,060 $ 12,862
Schedule of Assumptions Used to Determine Grant Date Fair Value of Employee Stock Options	The assumptions used to determine the grant date fair value of employee stock options for the periods presented are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Fair value of common stock $19.78 – $19.78 $18.18 – $19.56 $16.73 – $19.78 $15.78 – $19.56 Risk-free interest rate 1.9% – 2.0% 1.2% – 1.3% 1.9% – 2.1% 1.2% – 1.6% Expected term (in years) 6.0 – 6.1 6.1 – 6.2 6.0 – 6.1 6.0 – 8.1 Volatility 47% – 48% 50% – 51% 47% – 49% 47% – 51% Dividend yield —% —% —% —%

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share	The following table presents the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Net loss attributable to common stockholders $ (7,165 ) $ (18,312 ) $ (54,860 ) $ (57,960 ) Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted 6,139,876 5,749,930 6,032,427 5,539,012 Net loss per share attributable to common stockholders, basic and diluted $ (1.17 ) $ (3.18 ) $ (9.09 ) $ (10.46 )
Schedule of Securities Excluded from Computation of Diluted Net Loss Per Share	The following securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because their inclusion would reduce the net loss per share. As of September 30, 2017 2016 Options to purchase common stock 9,413,141 9,403,045 Unvested early exercised common shares 231,423 364,800 Unvested restricted stock units 3,031,223 1,039,121 Warrants to purchase common stock 233,023 233,023 Redeemable convertible preferred stock 24,788,362 24,788,362 Warrants to purchase redeemable convertible preferred stock 292,862 292,862

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Schedule of Revenue by Geographic Area	Revenue by geographic area is attributed based on the billing address of the customer and is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Revenue: Americas United States $ 50,348 $ 39,877 $ 119,409 $ 92,486 Other Americas 1,602 1,481 3,989 3,421 Total Americas 51,950 41,358 123,398 95,907 Europe, Middle East, and Africa (“EMEA”) 8,071 4,350 21,275 13,820 Asia Pacific and Japan (“APJ”) 4,335 3,032 10,242 7,684 Total revenue $ 64,356 $ 48,740 $ 154,915 $ 117,411
Schedule of Long-lived Assets by Geographical Area	Long-lived assets, net by geographic area are attributed based on legal entity structure and are as follows (in thousands): As of September 30, 2017 December 31, 2016 Long-lived assets, net: United States $ 19,682 $ 21,141 Israel 3,034 3,051 Other 548 344 Total long-lived assets, net $ 23,264 $ 24,536

Description of Business and S18

Description of Business and Summary of Significant Accounting Policies - Company Background (Details)	9 Months Ended
	Sep. 30, 2017product
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of products	3

Description of Business and S19

Description of Business and Summary of Significant Accounting Policies - IPO Transaction (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 01, 2017	Oct. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Subsidiary, Sale of Stock [Line Items]
Offering costs			$ 2,708	$ 0
Common stock, shares outstanding (shares)			6,175,126		5,854,147
Subsequent Event
Subsidiary, Sale of Stock [Line Items]
Shares converted into common stock (in shares)	335,838
Common stock, shares outstanding (shares)		37,861,342
IPO | Subsequent Event
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in IPO (in shares)		6,072,000
IPO price per share (in usd per share)		$ 22
Consideration received from IPO		$ 124,200
Offering costs		$ 3,500
Common stock | Subsequent Event
Subsidiary, Sale of Stock [Line Items]
Shares converted into common stock (in shares)		25,370,616

Description of Business and S20

Description of Business and Summary of Significant Accounting Policies - Stock Split (Details)	Oct. 16, 2017
Subsequent Event
Subsequent Event [Line Items]
Reverse stock split conversion ratio	0.50

Description of Business and S21

Description of Business and Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - Accounting Standards Update 2016-09 $ in Thousands	Dec. 31, 2016USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets	$ 2,300
Deferred tax assets, valuation allowance	2,300
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle	$ 34

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 72,344	$ 79,665
Restricted cash (current and non-current)	4,339	4,212
Total financial assets	76,683	83,877
Level 1 | Warrant liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities	0	0
Level 1 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	34,986	42,499
Level 1 | Money market accounts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	37,358	37,166
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Restricted cash (current and non-current)	0	0
Total financial assets	0	0
Level 3 | Warrant liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities	5,216	4,874
Level 3 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 3 | Money market accounts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 0	$ 0

Fair Value Measurements - Activ

Fair Value Measurements - Activity for Warrant Liabilities (Details) - Warrant liabilities $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of December 31, 2016	$ 4,874
Change in fair value of warrant liabilities	342
Balance as of September 30, 2017	$ 5,216

Equity Award Plans - Option Act

Equity Award Plans - Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Number of Shares
Balance beginning of the period (shares)	9,587,515
Options granted (shares)	458,099
Options exercised (shares)	(222,447)
Options forfeited (shares)	(410,026)
Balance end of the period (shares)	9,413,141	9,587,515
Weighted- Average Exercise Price
Balance beginning of the period (in dollars per share)	$ 10.13
Options granted (in dollars per share)	18.46
Options exercised (in dollars per share)	4.32
Options forfeited (in dollars per share)	14.31
Balance end of the period (in dollars per share)	$ 10.49	$ 10.13
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Options vested and expected to vest at end of period (shares)	9,413,141
Options vested and exercisable at end of period (shares)	5,014,239
Options vested and expected to vest at end of period (in dollars per share)	$ 10.49
Options vested and exercisable at end of period (in dollars per share)	$ 8.34
Balance, Weighted-Average Remaining Contractual Life (Years)	7 years 4 months 24 days	8 years
Options vested and expected to vest at end of period, Weighted-Average Remaining Contractual Life (Years)	7 years 4 months 24 days
Options vested and exercisable, Weighted Average-Remaining Contractual Life (Years)	6 years 9 months 18 days
Balance, Aggregate Intrinsic Value	$ 87,637	$ 61,865
Options vested and expected to vest at end of period, Aggregate Intrinsic Value	87,637
Options vested and exercisable at end of period, Aggregate Intrinsic Value	$ 57,377

Equity Award Plans - Narrative

Equity Award Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 31, 2017	Oct. 16, 2017	Sep. 30, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested options			$ 28.8
Option exercise price (in dollars per share)			$ 10.49	$ 10.13
Scenario, Forecast | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental compensation costs		$ 7.6
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Straight-line basis weighted-average amortization period			2 years 2 months 12 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested RSUs			$ 2.5
Straight-line basis weighted-average amortization period			1 year 4 months 24 days
Restricted stock units outstanding (shares)			3,031,223	1,898,623
Employee Stock Option and Restricted Stock Units, Vesting Upon Initial Public Offering Or Change In Control | Pro Forma
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 22.1
Unrecognized compensation costs related to performance based stock options and RSUs			$ 31
Weighted average amortization period for unrecognized compensation costs related to performance based stock options and RSUs			1 year 10 months 24 days
Employee Stock Option, Vesting Upon Initial Public Offering Or Change In Control
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested options outstanding (shares)			294,160
Employee Stock Option, Vesting Upon Initial Public Offering Or Change In Control | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option exercise price (in dollars per share)			$ 0.43
Employee Stock Option, Vesting Upon Initial Public Offering Or Change In Control | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option exercise price (in dollars per share)			$ 1.47
Restricted Stock Units, Vesting Upon Initial Public Offering Or Change In Control
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding (shares)			2,420,273
Stock options and RSUs | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 24.1

Equity Award Plans - RSU Activi

Equity Award Plans - RSU Activity (Details) - RSUs - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Number of Shares
Balance at beginning of period (shares)	1,898,623
RSUs granted (shares)	1,155,350
RSUs forfeited (shares)	(22,750)
Balance at end of period (shares)	3,031,223	1,898,623
Weighted- Average Grant Date Fair Value Per Share
Balance at beginning of period (in dollars per share)	$ 14.83
RSUs granted (in dollars per share)	19.25
RSUs forfeited (in dollars per share)	20.18
Balance at end of period (in dollars per share)	$ 16.48	$ 14.83
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
RSUs vested and expected to vest at end of period (shares)	3,029,970
RSUs vested and expected to vest at end of period (in dollars per share)	$ 17.22
Balance, Weighted- Average Remaining Contractual Life (Years)	1 year 9 months 18 days	1 year 8 months 12 days
RSUs vested and expected to vest at end of period, Weighted-Average Remaining Contractual Life (Years)	1 year 9 months 18 days
Balance, Aggregate Intrinsic Value	$ 59,958	$ 30,720
RSUs vested and expected to vest at end of period, Aggregate Intrinsic Value	$ 59,933

Equity Award Plans - Stock-base

Equity Award Plans - Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 3,909	$ 3,818	$ 12,060	$ 12,862
Product
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	19	6	60	16
Maintenance and professional services
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	286	317	930	809
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	630	613	2,043	1,645
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,602	1,543	4,868	6,469
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,372	$ 1,339	$ 4,159	$ 3,923

Equity Award Plans - Assumption

Equity Award Plans - Assumptions (Details) - Employee stock options - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	1.90%	1.20%	1.90%	1.20%
Risk-free interest rate, maximum	2.00%	1.30%	2.10%	1.60%
Volatility, minimum	47.00%	50.00%	47.00%	47.00%
Volatility, maximum	48.00%	51.00%	49.00%	51.00%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years	6 years 1 month 6 days	6 years	6 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 2 months 12 days	6 years 1 month 6 days	8 years 1 month 6 days
Common stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)	$ 19.78	$ 18.18	$ 16.73	$ 15.78
Common stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)	$ 19.78	$ 19.56	$ 19.78	$ 19.56

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income tax provision	$ 412	$ 157	$ 1,221	$ 517
Effective tax rate	(6.10%)	(0.90%)	(2.30%)	(0.90%)

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net loss attributable to common stockholders	$ (7,165)	$ (18,312)	$ (54,860)	$ (57,960)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (shares)	6,139,876	5,749,930	6,032,427	5,539,012
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (1.17)	$ (3.18)	$ (9.09)	$ (10.46)

Net Loss Per Share - Securities

Net Loss Per Share - Securities Excluded from Diluted Net Loss Per Share (Details) - shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	9,413,141	9,403,045
Unvested early exercised common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	231,423	364,800
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	3,031,223	1,039,121
Warrants to purchase | Common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	233,023	233,023
Warrants to purchase | Redeemable convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	292,862	292,862
Redeemable convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	24,788,362	24,788,362

Segment Information - Narrative

Segment Information - Narrative (Details)	9 Months Ended
	Sep. 30, 2017business_activitysegment
Segment Reporting [Abstract]
Number of business activities | business_activity	1
Single reportable segment	1
Single operating unit structure	1

Segment Information - Revenue (

Segment Information - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 64,356	$ 48,740	$ 154,915	$ 117,411
Total Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	51,950	41,358	123,398	95,907
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	50,348	39,877	119,409	92,486
Other Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,602	1,481	3,989	3,421
Europe, Middle East, and Africa (“EMEA”)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	8,071	4,350	21,275	13,820
Asia Pacific and Japan (“APJ”)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 4,335	$ 3,032	$ 10,242	$ 7,684

Segment Information - Long-live

Segment Information - Long-lived Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 23,264	$ 24,536
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	19,682	21,141
Israel
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	3,034	3,051
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 548	$ 344

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Nov. 01, 2017	Oct. 31, 2017	Oct. 16, 2017	Oct. 27, 2017	Sep. 30, 2017
Subsequent Event [Line Items]
Convertible preferred stock, initial public offering price threshold (in usd per share)					$ 29.66
Subsequent Event
Subsequent Event [Line Items]
Shares issued as stock dividend (in shares)		582,254
Warrants to purchase common stock (in shares)	442,648
Exercise price (in dollars per share)	$ 6.62			$ 6
Shares issued, price per share (in dollars per share)	$ 25.73
Shares converted into common stock (in shares)	335,838
2017 Equity Incentive Plan | Subsequent Event
Subsequent Event [Line Items]
Common stock reserved for issuance (in shares)			3,800,000
Maximum number of shares authorized to be added to the Plan (in shares)			12,500,000
Annual increase to shares available for future issuance (in shares)			3,800,000
Percentage of common stock outstanding annual increase to shares available for issuance			5.00%
2017 Employee Stock Purchase Plan | Subsequent Event
Subsequent Event [Line Items]
Common stock reserved for issuance (in shares)			800,000
Percentage of common stock outstanding annual increase to shares available for issuance			1.00%
Offering period			6 months
Participants maximum percentage of annual salary			15.00%
Discount rate on offering period			85.00%
Discount rate on date of exercise			85.00%
IPO | Subsequent Event
Subsequent Event [Line Items]
IPO price per share (in usd per share)		$ 22