Forescout (FSCT) 10-K 28 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 14, 2020	Jun. 28, 2019
Cover page.
Document Type	10-K
Document Fiscal Period Focus	FY
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Amendment Flag	false
Document Fiscal Year Focus	2019
Current Fiscal Year End Date	--12-31
Entity File Number	001-38253
Entity Registrant Name	FORESCOUT TECHNOLOGIES, INC.
Entity Central Index Key	0001145057
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	51-0406800
Entity Address, Address Line One	190 West Tasman Drive
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95134
City Area Code	408
Local Phone Number	213-3191
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	FSCT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1,492,156,938
Entity Common Stock, Shares Outstanding		48,404,973
Documents Incorporated by Reference	Portions of the information called for by Part III of this Annual Report on Form 10-K are hereby incorporated by reference where indicated from the definitive proxy statement for the registrant’s annual meeting of stockholders, which will be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2019 .

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 69,030	$ 66,895
Marketable securities	29,181	47,632
Accounts receivable	84,168	79,255
Inventory	372	1,501
Deferred commissions - current	12,843	12,543
Prepaid expenses and other current assets	17,024	13,353
Total current assets	212,618	221,179
Deferred commissions - non-current	23,036	22,831
Property and equipment, net	23,835	24,349
Operating lease right-of-use assets	29,626
Restricted cash - non current	1,555	1,266
Intangible assets, net	19,367	19,002
Goodwill	98,018	92,482
Other assets	8,172	7,369
Total assets	416,227	388,478
Current liabilities:
Accounts payable	10,692	12,118
Accrued compensation	34,007	32,649
Accrued expenses	16,279	14,558
Deferred revenue - current	112,232	101,900
Notes payable - current	8,248	7,331
Operating lease liabilities - current	5,840
Total current liabilities	187,298	168,556
Deferred revenue - non-current	75,366	69,618
Notes payable - non-current	0	8,248
Operating lease liabilities - non-current	32,125
Other liabilities	23,893	14,335
Total liabilities	318,682	260,757
Commitments and contingencies (Note 8)
Stockholders' equity:
Preferred stock, $0.001 par value; 100,000 shares authorized; zero shares issued and outstanding at December 31, 2019 and 2018.	0	0
Common stock, $0.001 par value; 1,000,000 shares authorized; 48,064 and 43,403 shares issued and outstanding at December 31, 2019 and 2018, respectively.	48	43
Additional paid-in capital	727,922	639,237
Accumulated other comprehensive loss	(633)	(302)
Accumulated deficit	(629,792)	(511,257)
Total stockholders’ equity	97,545	127,721
Total liabilities and stockholders' equity	$ 416,227	$ 388,478

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (shares)	100,000	100,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (shares)	48,064,000	43,403,000
Common stock, shares outstanding (shares)	48,064,000	43,403,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Revenue	$ 91,331	$ 91,622	$ 78,280	$ 75,568	$ 84,732	$ 85,628	$ 67,594	$ 59,697	$ 336,801	$ 297,651	$ 224,404
Cost of revenue:
Cost of revenue	21,025	21,697	17,456	19,000	17,486	19,197	14,713	16,486	79,178	67,882	58,612
Total gross profit	70,306	69,925	60,824	56,568	67,246	66,431	52,881	43,211	257,623	229,769	165,792
Operating expenses:
Research and development	24,302	20,556	19,440	18,497	17,161	15,062	14,803	14,687	82,795	61,713	47,435
Sales and marketing	49,915	51,035	56,173	55,923	50,464	46,098	45,039	42,279	213,046	183,880	144,398
General and administrative	15,649	15,318	15,838	16,213	16,849	13,880	13,260	13,732	63,018	57,721	51,206
Total operating expenses	89,866	86,909	91,451	90,633	84,474	75,040	73,102	70,698	358,859	303,314	243,039
Loss from operations	(19,560)	(16,984)	(30,627)	(34,065)	(17,228)	(8,609)	(20,221)	(27,487)	(101,236)	(73,545)	(77,247)
Interest expense	(105)	(156)	(142)	(93)	(237)	(208)	(225)	(243)	(496)	(913)	(1,223)
Other income, net	422	374	505	617	527	865	513	662	1,918	2,567	316
Revaluation of warrant liabilities									0	0	(727)
Loss before income taxes	(19,243)	(16,766)	(30,264)	(33,541)	(16,938)	(7,952)	(19,933)	(27,068)	(99,814)	(71,891)	(78,881)
Income tax provision	767	16,747	496	711	1,010	334	473	1,128	18,721	2,945	1,839
Net loss	$ (20,010)	$ (33,513)	$ (30,760)	$ (34,252)	$ (17,948)	$ (8,286)	$ (20,406)	$ (28,196)	(118,535)	(74,836)	(80,720)
Deemed dividend on the conversion of Series G redeemable convertible preferred stock									0	0	12,810
Net loss attributable to common stockholders									$ (118,535)	$ (74,836)	$ (93,530)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.42)	$ (0.72)	$ (0.68)	$ (0.78)	$ (0.42)	$ (0.20)	$ (0.50)	$ (0.74)	$ (2.58)	$ (1.83)	$ (8.20)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (in shares)	47,511	46,584	45,494	44,196	43,016	42,064	40,457	38,313	45,957	40,980	11,405
License
Revenue:
Revenue	$ 48,401	$ 50,203	$ 38,831	$ 37,680	$ 47,482	$ 51,082	$ 34,323	$ 29,780	$ 175,115	$ 162,667	$ 125,348
Cost of revenue:
Cost of revenue	8,180	9,892	5,622	7,607	6,852	8,947	4,919	7,136	31,301	27,854	23,841
Subscription
Revenue:
Revenue	37,586	36,570	34,822	33,799	32,888	30,339	28,986	26,359	142,777	118,572	86,691
Cost of revenue:
Cost of revenue	5,795	5,376	5,599	5,207	4,613	4,069	3,732	3,801	21,977	16,215	13,912
Professional services
Revenue:
Revenue	5,344	4,849	4,627	4,089	4,362	4,207	4,285	3,558	18,909	16,412	12,365
Cost of revenue:
Cost of revenue	$ 7,050	$ 6,429	$ 6,235	$ 6,186	$ 6,021	$ 6,181	$ 6,062	$ 5,549	$ 25,900	$ 23,813	$ 20,859

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (118,535)	$ (74,836)	$ (80,720)
Other comprehensive loss, net of tax:
Change in unrealized gains (losses) on marketable securities	121	9	(112)
Foreign currency translation adjustments	(452)	(199)	0
Comprehensive loss	$ (118,866)	$ (75,026)	$ (80,832)

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	$ 34				$ 34
Redeemable convertible preferred stock, beginning balance (in shares) at Dec. 31, 2016	18,469,000
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2016	$ 283,854
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock in connection with the initial public offering (in shares)	(18,525,000)
Conversion of redeemable convertible preferred stock to common stock in connection with the initial public offering	$ (283,854)
Shares issued for preferred stock warrant exercise (in shares)	56,000
Shares issued for preferred stock warrant exercise	$ 0
Redeemable convertible preferred stock, ending balance (in shares) at Dec. 31, 2017	0
Redeemable convertible preferred stock, ending balance at Dec. 31, 2017	$ 0
Stockholders' (deficit) equity, beginning balance (in shares) at Dec. 31, 2016		5,854,000
Stockholders' (deficit) equity, beginning balance at Dec. 31, 2016	(258,127)	$ 6	$ 84,792	$ 0	(342,925)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on marketable securities	(112)			(112)
Stock-based compensation	42,562		42,562
Issuance of common stock in connection with employee equity incentive plans (in shares)		306,000
Issuance of common stock in connection with employee equity incentive plans	1,626	$ 0	1,626
Issuance of common stock in connection with public offering, net of underwriter discounts and commissions and offering costs (in shares)		6,072,000
Issuance of common stock in connection with public offering, net of underwriter discounts and commissions and offering costs	119,684	$ 6	119,678
Conversion of redeemable convertible preferred stock to common stock in connection with the initial public offering (in shares)		24,845,000
Conversion of redeemable convertible preferred stock to common stock in connection with the initial public offering	283,854	$ 25	283,829
Conversion of preferred stock warrants to common stock warrants in connection with initial public offering	4,173		4,173
Vesting of early exercised stock options (in shares)		183,000
Vesting of early exercised stock options	1,089		1,089
Issuance of common stock upon exercise of common stock warrants (in shares)		280,000
Shares issued for preferred stock warrant exercise	1,428		1,428
Deemed dividend on the conversion of Series G redeemable convertible preferred stock (in shares)		582,000
Deemed dividend on the conversion of Series G redeemable convertible preferred stock	0	$ 1	12,809		(12,810)
Net loss	(80,720)				(80,720)
Stockholders' (deficit) equity, ending balance (in shares) at Dec. 31, 2017		38,122,000
Stockholders' (deficit) equity, ending balance at Dec. 31, 2017	$ 115,491	$ 38	551,986	(112)	(436,421)
Redeemable convertible preferred stock, ending balance (in shares) at Dec. 31, 2018	0
Redeemable convertible preferred stock, ending balance at Dec. 31, 2018	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on marketable securities	9
Other comprehensive loss, net of tax	(190)			(190)
Stock-based compensation	$ 53,497		53,497
Issuance of common stock in connection with employee equity incentive plans (in shares)	2,979,000	4,616,000
Issuance of common stock in connection with employee equity incentive plans	$ 20,347	$ 5	20,342
Issuance of common stock in connection with public offering, net of underwriter discounts and commissions and offering costs (in shares)		500,000
Issuance of common stock in connection with public offering, net of underwriter discounts and commissions and offering costs	12,572	$ 0	12,572
Vesting of early exercised stock options (in shares)		98,000
Vesting of early exercised stock options	840		840
Issuance of common stock upon exercise of common stock warrants (in shares)		67,000
Net loss	$ (74,836)				(74,836)
Stockholders' (deficit) equity, ending balance (in shares) at Dec. 31, 2018	43,403,000	43,403,000
Stockholders' (deficit) equity, ending balance at Dec. 31, 2018	$ 127,721	$ 43	639,237	(302)	(511,257)
Redeemable convertible preferred stock, ending balance (in shares) at Dec. 31, 2019	0
Redeemable convertible preferred stock, ending balance at Dec. 31, 2019	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on marketable securities	121
Other comprehensive loss, net of tax	(331)			(331)
Stock-based compensation	$ 55,055		55,055
Issuance of common stock in connection with employee equity incentive plans (in shares)	2,744,000	4,613,000
Issuance of common stock in connection with employee equity incentive plans	$ 33,230	$ 5	33,225
Vesting of early exercised stock options (in shares)		48,000
Vesting of early exercised stock options	405		405
Net loss	$ (118,535)				(118,535)
Stockholders' (deficit) equity, ending balance (in shares) at Dec. 31, 2019	48,064,000	48,064,000
Stockholders' (deficit) equity, ending balance at Dec. 31, 2019	$ 97,545	$ 48	$ 727,922	$ (633)	$ (629,792)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net loss	$ (118,535)	$ (74,836)	$ (80,720)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities
Stock-based compensation	55,450	53,497	42,596
Depreciation and amortization	11,912	8,003	6,068
Revaluation of warrant liabilities	0	0	727
Other	38	461	(127)
Changes in operating assets and liabilities, net of business acquisition
Accounts receivable	(5,220)	(10,899)	(19,992)
Inventory	1,129	2,168	(2,719)
Deferred commissions	(506)	(2,621)	(7,469)
Prepaid expenses and other current assets	(2,289)	(3,084)	(141)
Other assets	(188)	(3,543)	60
Accounts payable	(1,239)	4,632	1,734
Accrued compensation	1,370	7,057	8,072
Accrued expenses	3,415	2,667	(599)
Deferred revenue	15,939	30,366	49,569
Other liabilities	16,200	(379)	206
Net cash (used in) provided by operating activities	(22,524)	13,489	(2,735)
Cash flows from investing activities
Purchases of property and equipment	(7,760)	(7,628)	(4,517)
Purchases of marketable securities	(63,569)	(54,530)	(123,032)
Proceeds from maturities of marketable securities	82,345	130,633	0
Business acquisition, net of cash acquired	(10,271)	(105,425)	0
Net cash provided by (used in) investing activities	745	(36,950)	(127,549)
Cash flows from financing activities
Repayments of notes payable	(7,500)	(7,500)	(7,500)
Payment of accrued success fees	0	0	(350)
Proceeds from sales of shares through employee equity incentive plans	36,380	31,790	1,626
Payment related to shares withheld for taxes on vesting of restricted stock units	(4,538)	(11,443)	0
Payments of deferred offering costs	0	(1,542)	(4,245)
Proceeds from public offering, net of underwriting discounts and commissions	0	13,818	124,233
Others	20	0	0
Net cash provided by financing activities	24,362	25,123	113,764
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(4)	(7)	0
Net change in cash, cash equivalents, and restricted cash for period	2,579	1,655	(16,520)
Cash, cash equivalents, and restricted cash at beginning of period	69,012	67,357	83,877
Cash, cash equivalents, and restricted cash at end of period	71,591	69,012	67,357
Supplemental disclosure of cash flow information:
Cash paid for income taxes	3,286	1,447	1,634
Cash paid for interest	384	628	819
Noncash disclosure of investing and financing activities:
Change in liability for early exercise of stock options, net of vested portion	405	840	1,089
Conversion of preferred stock warrants to common stock warrants in connection with initial public offering	0	0	4,173
Cashless exercise of preferred stock warrants	0	0	1,428
Leased assets obtained in exchange for new operating lease liabilities	15,159
Reconciliation of cash, cash equivalents, and restricted cash within the consolidated balance sheets to the amounts shown in the statements of cash flows above:
Total cash, cash equivalents, and restricted cash	$ 71,591	$ 67,357	$ 67,357

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
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 designs, develops, and markets device visibility, control, and orchestration software that helps organizations gain complete situational awareness of all devices in their interconnected environment and orchestrate actions to mitigate both their cyber and operational risk. The Company offers its solution across two product groups: (i) products for visibility and control capabilities, and (ii) products for orchestration capabilities. The Company’s products for visibility and control capabilities consist of eyeSight, eyeSegment, eyeControl, and SilentDefense. eyeSight, eyeSegment, and eyeControl provide for visibility and control capabilities across the extended enterprise, from campus to data center to hybrid cloud to operational technology (“OT”) devices, while SilentDefense provides for visibility and control capabilities deeper within the OT portion of the network. The Company’s products for orchestration capabilities are comprised of its portfolio of eyeExtend family of products. The Company offers its solution across two product types: (i) software products and (ii) hardware products. The Company’s software products include eyeSight, eyeSegment, eyeControl, eyeExtend, SilentDefense, and SilentDefense Command Center (“Software Products”). The Company’s hardware products include hardware that is sold separately for use with the Company’s Software Products and appliances that are embedded with the Company’s software (“Hardware Products”). The Company sells its Software Products, Hardware Products, support and maintenance contracts, 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 $4.5 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. Follow-On Offering The Company closed its follow-on offering (the “Offering”) in March 2018, in which it issued and sold 500,000 shares of its common stock. Further, an additional 4,572,650 shares of its common stock were sold by certain stockholders in the Offering, inclusive of the underwriters’ option to purchase additional shares from certain of the selling stockholders. The price to the public was $29.00 per share. The Company received aggregate proceeds of $16.4 million from the Offering, net of underwriters’ discounts and commissions of $0.7 million and inclusive of approximately $2.6 million received by the Company in connection with the exercise by certain selling stockholders of options to purchase an aggregate of 425,436 shares of common stock that were sold in the Offering. The Company incurred offering costs of approximately $1.2 million . The Company did not receive any proceeds from the sale of shares by the selling stockholders in the Offering. Basis of Presentation The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The Company’s 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. Reclassifications Certain amounts in prior periods have been reclassified to conform with current period presentation. In prior years, the Company presented revenue and cost of revenue on the consolidated statements of operations as (i) product and (ii) maintenance and professional services. Under the current presentation of revenue and cost of revenue included in the consolidated statements of operations, product has been retitled as license revenue, and maintenance and professional services is now presented as two separate line items on the consolidated statements of operations as (i) subscription and (ii) professional services. The related prior period financial data were adjusted to reflect the new presentation of the Company’s revenue and cost of revenue. There is no impact on total revenue and total cost of revenue. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make use of estimates and assumptions that affect the reported amounts in the 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 best estimate of selling prices for products and related support, the period over which deferred sales commissions are amortized to expense, sales return reserve, accruals, stock-based compensation including the fair value of common stock, redeemable convertible preferred stock warrant liabilities, provision for income taxes, including related reserves, identified intangibles and goodwill, and purchase price allocation of an acquired business. 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 consolidated financial statements herein, and notes thereto, have been retroactively adjusted to reflect the Reverse Stock Split. Segment Information The chief operating decision maker (“CODM”) is the Chief Executive Officer who reviews financial information presented on a consolidated basis. The Company has one business activity and there are no segment managers who are held accountable by the CODM for operations, operating results and planning for levels or components below the consolidated level. The Company operates in one segment. Concentrations Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities, accounts receivable, and restricted cash. The Company maintains all of its cash and cash equivalents in interest-bearing bank accounts and money market accounts. Management believes that the financial institutions that hold the Company’s cash and cash equivalents are financially sound and exposed to minimal credit risk. Deposits held with banks generally exceed the amount of insurance provided on such deposits. Accounts receivable are primarily derived from the Company’s customers, including distributors and resellers representing various geographical locations. The Company performs ongoing credit evaluations of its customers and generally does not require collateral on accounts receivable, and, if necessary, an allowance for doubtful accounts is maintained for estimated potential credit losses. As of December 31, 2019 and 2018 , two customers represented 17% and 17% of total accounts receivable, and four customers represented 17% , 15% , 11% , and 11% of total accounts receivable, respectively. For the year ended December 31, 2019 , three customers represented 22% , 18% , and 12% of the Company’s total revenue. For the year ended December 31, 2018 , three customers represented 22% , 18% , and 13% of the Company’s total revenue. For the year ended December 31, 2017 , three customers represented 31% , 22% , and 16% of the Company’s total revenue. The Company purchases its hardware appliances from one contract manufacturer that assembles all of its products. Foreign Currency Prior to July 1, 2019, the Company’s functional currency was the U.S. dollar for the majority of its foreign operations except for Forescout Technologies, B.V. whose functional currency was the Euro. Translation gains and losses from the application of the U.S. dollar as the reporting currency during the period that the Euro was the functional currency for Forescout Technologies, B.V. were included as a component of accumulated other comprehensive loss on the consolidated balance sheets. The Company re-assessed its functional currency and determined that, as of July 1, 2019, its functional currency for Forescout Technologies, B.V. had changed from the Euro to the U.S. dollar following the transfer of all of the intellectual property from Forescout Technologies, B.V. to the Company effective July 1, 2019. The change in functional currency was accounted for prospectively from July 1, 2019 and financial statements prior to and including the period ended June 30, 2019 were not restated for the change in functional currency. Transactions denominated in currencies other than the applicable functional currency are converted to the functional currency at the exchange rate on the transaction date. At period end, monetary assets and liabilities are remeasured using the current exchange rate at the balance sheet date. Non-monetary assets and liabilities and capital accounts are remeasured using historical exchange rates. Revenue and expenses have been remeasured using the average exchange rates in effect during each period. Resulting foreign currency remeasurement gains and losses are recorded in other income (expense), net on the consolidated statements of operations. Where a non-U.S. currency is the functional currency, translation from that functional currency to the U.S. dollar is performed for balance sheet accounts using exchange rates in effect at the balance sheet date and for revenue and expense accounts using an average exchange rate for the period. Resulting translation adjustments are reported as a component of accumulated other comprehensive loss on the consolidated balance sheets. Cash and Cash Equivalents The Company considers all highly liquid investments held at financial institutions with original maturities of three months or less at date of purchase to be cash equivalents. Cash and cash equivalents are stated at cost, which approximates fair value. Marketable Securities The Company’s marketable securities consist primarily of commercial paper, corporate debt securities, and U.S. government agency securities. The Company’s marketable securities are classified as available-for-sale and are reported at fair value. The Company determines any realized gains or losses on the sale of available-for-sale securities on a specific identification method, and such gains and losses are recorded as a component of other income, net on the consolidated statements of operations. Unrealized gains and losses of the available-for-sale securities are excluded from earnings and reported as a component of accumulated other comprehensive loss. The Company has classified and accounted for its marketable securities as available-for-sale. After consideration of the Company’s risk versus reward objectives, as well as the Company’s liquidity requirements, the Company may sell these securities prior to their stated maturities. As the Company views these securities as available to support current operations, the Company classifies highly liquid securities with maturities beyond 12 months as current assets under the caption marketable securities in the consolidated balance sheets. Marketable securities are considered impaired when a decline in fair value is judged to be other-than-temporary. The Company considers available quantitative and qualitative evidence in evaluating potential impairment of the marketable securities on a quarterly basis. If the cost of an individual investment exceeds its fair value, the Company evaluates, among other factors, general market conditions, the duration and extent to which the fair value is less than cost, and the Company’s intent and ability to hold the investment. Once a decline in fair value is determined to be other-than-temporary, the Company will record an impairment charge and establish a new cost basis in the investment. As of December 31, 2019 , the Company did not consider any of its marketable securities to be other-than-temporarily impaired. Restricted Cash As of December 31, 2019 and 2018 , the Company had restricted cash of $1.0 million and $0.9 million recorded as prepaid expenses and other current assets, respectively, and $1.6 million and $1.3 million recorded as non-current restricted cash, respectively. Restricted cash primarily consists of letters of credit issued as security deposits required for facility leases. Accounts Receivable Trade accounts receivable are recorded at the invoiced amount, net of allowances for doubtful accounts. The Company assesses its trade accounts receivable for doubtful accounts based on the collectability of accounts. Management regularly reviews the adequacy of the allowance for doubtful accounts by considering the age of each outstanding invoice, each customer’s expected ability to pay, and the collection history with each customer, to determine whether a specific allowance is appropriate. Accounts receivable that are deemed uncollectible are charged against the allowance for doubtful accounts. Based on management’s assessment of its trade accounts receivable, the Company did not record an allowance for doubtful accounts as of December 31, 2019 and 2018 . Inventory Inventory primarily consists of finished goods hardware appliances and production materials. Inventory is stated at the lower of cost or net realizable value 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. There were no material inventory write-downs for the years ended December 31, 2019 , 2018 , and 2017 . Property and Equipment Property and equipment is stated at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally three to five years . Demonstration units are not resold after use and are depreciated over the estimated useful life of three years or less. Leasehold improvements are depreciated over the shorter of the estimated useful lives of the improvements or the remaining lease term. Business Combinations The Company accounts for acquisitions using the acquisition method of accounting for business combinations . When the Company acquires a business, the purchase price is allocated to the net tangible and identifiable intangible assets acquired based on their estimated fair values. Any residual purchase price is recorded as goodwill. The allocation of the purchase price requires management to make significant estimates in determining the fair values of assets acquired and liabilities assumed, especially with respect to intangible assets. These estimates can include, but are not limited to, the cash flows that an asset is expected to generate in the future, the appropriate weighted-average cost of capital, and the cost savings expected to be derived from acquiring an asset. These estimates are inherently uncertain and unpredictable. During the measurement period, which may be up to one year from the acquisition date, adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed may be recorded, with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of operations. Goodwill and Other Long-Lived Assets The excess of the purchase price over the estimated fair value of net assets of businesses acquired in a business combination is recognized as goodwill. Goodwill is tested for impairment annually on October 1st or more frequently if certain indicators are present. Management reviews long-lived assets, such as property and equipment and finite-lived intangible assets subject to amortization, for events and changes in circumstances that may indicate that carrying amounts of long-lived assets may not be recoverable. When such events or circumstances occur, recoverability of these assets is measured by a comparison of the carrying value to the future undiscounted cash flows the assets are expected to generate. If long-lived assets are considered to be impaired, the impairment to be recognized would equal the amount by which the carrying value of the asset exceeds its fair market value. To date, the Company has not recorded any significant impairment to its goodwill and other long-lived assets. Deferred Offering Costs Deferred offering costs consisted of fees and expenses incurred in connection with the sale of the Company’s common stock in its IPO and Offering, including direct incremental legal, consulting, accounting fees, and other offering-related costs. Upon completion of the Company’s IPO or Offering, these deferred offering costs were reclassified to stockholders’ equity and offset against the proceeds of the offerings. Product Warranty The Company provides a standard 90 day warranty on its hardware and software products. The Company also offers its customers post-contract support (“PCS”), which includes a warranty of between one to five -years on hardware. The Company will also provide its customers software releases or updates during the PCS term. The Company accrues for estimated standard warranty costs for those customers that do not purchase PCS at the time of product shipment. These potential warranty claims are accrued as a component of product cost of revenue based on historical experience and other data, which is reviewed periodically for adequacy. Warranty costs associated with PCS are expensed as incurred. To date, the Company has not incurred nor accrued any significant costs associated with product warranty. Leases Refer to Note 6 for a detailed discussion of accounting policies related to leases, including right-of-use (“ROU”) assets, lease liabilities, and lease expense. Contract Manufacturer Liabilities Manufacturing, repair, and supply chain management operations are outsourced to a third-party contract manufacturer. These costs are a significant portion of product cost of revenue. Although the Company is contractually obligated to purchase manufactured products, the Company generally does not own the manufactured products as product title transfers from the contract manufacturer to the Company and immediately to the customer upon shipment. The contract manufacturer assembles the Company’s products using design specifications, quality assurance programs, and standards that the Company establishes. Components are procured and assembled based on the Company’s demand forecasts. These forecasts represent management’s best estimates of future demand for the products based upon historical trends and analysis from sales and operations functions as adjusted for overall market conditions. The Company accrues for costs for contractual manufacturing commitments in excess of its forecasted demand, including costs incurred for excess components or for the carrying costs incurred by the contract manufacturer. To date, the Company has not accrued any significant contract manufacturer liabilities. Redeemable Convertible Preferred and Common Stock Warrant Liabilities Upon completion of the Company's IPO in October 2017, there were no freestanding warrants to purchase shares of convertible preferred stock. As such, no preferred stock warrant liability remained outstanding after the IPO. Before the Company's IPO, freestanding warrants related to shares that are redeemable or contingently redeemable were classified as a liability in the Company’s consolidated balance sheet. The convertible preferred stock warrants were subject to re-measurement at each balance sheet date, and any change in fair value was recognized in the consolidated statements of operations. The Company adjusted the redeemable convertible preferred stock warrant liability to the estimated fair value of the warrants until either the exercise or the completion of the Company’s IPO, at which time the redeemable convertible preferred stock issuable upon exercise of the warrants became warrants to purchase common stock and the related liability was reclassified to additional paid-in capital in stockholders' equity. Severance Pay Deposits and Accrued Severance Pay Liability The Company records a severance pay asset and liability on its consolidated balance sheets related to its employees located in Israel. Under Israeli law and labor agreements, the Company is required to make severance and pension payments to retired or dismissed employees and to employees leaving employment in certain other circumstances. Liabilities for severance pay are calculated pursuant to Israeli severance pay law using the most recent monthly salary for the employees, multiplied by the number of years of employment, and are included in accrued expenses and other liabilities in the Company’s consolidated balance sheets for the current and non-current portions, respectively. The Company’s liability at each respective balance sheet date for its Israeli employees is fully accrued in the accompanying consolidated financial statements. The severance liability is funded through monthly deposits to the employee’s pension and management insurance carriers. The fair value of this deposit is recorded in prepaid expenses and other current assets, and other assets in the Company’s consolidated balance sheets for the current and non-current portions, respectively. Revenue Recognition Refer to Note 2 for a detailed discussion of accounting policies related to revenue recognition, including deferred revenue and commissions. Software Development Costs Software development costs are not capitalized as the software development process is essentially completed concurrent with the establishment of technological feasibility. As such, all software development costs are expensed as incurred and included in research and development expense in the accompanying consolidated statements of operations. Advertising Costs Advertising costs include costs incurred on print, broadcast, and online advertising. Advertising costs are expensed as incurred and included in sales and marketing expense in the accompanying consolidated statements of operations. Stock-Based Compensation Stock-based compensation for employees is measured based on the grant date fair value of the award and is expensed over the requisite service period, which is generally the vesting period. The fair value of option awards is determined on the date of grant using the Black-Scholes option pricing model. In applying the Black-Scholes option pricing model, the Company’s determination of the fair value of the option award on the grant date prior to its IPO is affected by the Company’s estimated fair value of the underlying common stock, as well as assumptions relating to subjective variables. Subsequent to its IPO, the Company uses the market closing price for its common stock as reported on the NASDAQ Global Select Market. These variables include the expected term of the award, the expected volatility of the common stock price, the risk-free interest rate, and the expected dividend yield of common stock. Prior to the IPO, the fair value of restricted stock units (“RSUs”) was determined on the date of grant using the Company’s estimated fair value of the underlying common stock. Subsequent to its IPO, the Company uses the market closing price for its common stock as reported on the NASDAQ Global Select Market. Beginning January 1, 2017 with the adoption of Accounting Standards Update (“ASU”) No. 2016-09, the Company elected to recognize forfeitures as they occur, and no longer estimates a forfeiture rate when calculating the stock-based compensation for equity awards. Income Taxes Deferred income taxes are recognized using the asset and liability method, whereby deferred tax assets and liabilities are recognized for the expected future tax consequences attributable to differences between the Company’s (1) financial statement carrying amounts and their respective tax bases and (2) operating loss and tax credit carryforwards. Valuation allowances are provided when the expected realization of tax assets does not meet a more-likely-than-not criterion. Due to the Company’s lack of earnings history, the U.S. net deferred tax assets have been fully offset by a valuation allowance. The Company recognizes tax benefits from uncertain tax positions if it is more likely than not that the tax position will be sustained upon examination by a taxing authority based on the technical merits of the position. The tax benefits recognized from such positions are measured based on the largest benefit that has a greater than 50% likelihood to be realized upon settlement. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense in the accompanying consolidated statements of operations, when and if incurred. Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02 (Topic 842), Leases (“ASU 2016-02”), followed by ASU No. 2018-10 (Topic 842), Codification Improvements to Topic 842, Leases (“ASU 2018-10”), and ASU No. 2018-11 (Topic 842), Targeted Improvements (“ASU 2018-11”) in July 2018 (collectively, “Topic 842”). The Company adopted Topic 842 effective January 1, 2019 using the transition method. See Note 6 for the details of any impact on the adoption. Recently Issued and Not Yet Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model which requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. The Company will adopt ASU 2016-13 effective January 1, 2020 with the cumulative effect of adoption recorded as an adjustment to retained earnings. The effect on its consolidated financial statements and related disclosures is not expected to be material. In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes that eliminates certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. The standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted. The Company is currently evaluating the timing and impact of the adoption of this standard on its consolidated financial statements.

Revenue, Deferred Revenue and D

Revenue, Deferred Revenue and Deferred Commissions	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue, Deferred Revenue and Deferred Commissions	Revenue, Deferred Revenue and Deferred Commissions Revenue Recognition The Company derives its revenue from sale of Software Products, Hardware Products, term contracts, and professional services. All revenue recognized in the consolidated statements of operations is considered to be revenue from contracts with customers. The Company offers its solution across two product groups: (i) products for visibility and control capabilities, and (ii) products for orchestration capabilities and across two product types: (i) software products, and (ii) hardware products. The Company determines revenue recognition through the following steps, which are described in more detail below: • Identification of the contract, or contracts, with a customer — A contract with a customer exists when (i) the Company enters into an enforceable contract with a customer that defines each party’s rights regarding the goods or services to be transferred and identifies the payment terms related to these goods or services, (ii) the contract has commercial substance, and (iii) the Company determines that collection of substantially all consideration for goods or services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration. The Company applies judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors, including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information pertaining to the customer. The Company’s payment terms typically range between 30 to 90 days. • Identification of the performance obligation(s) in the contract — Performance obligations promised in a contract are identified based on the goods or services that will be transferred to the customer that are both capable of being distinct, whereby the customer can benefit from the goods or services either on their own or together with other resources that are readily available from third parties or from the Company, and are distinct in the context of the contract, whereby the transfer of the goods or services is separately identifiable from other promises in the contract. To the extent a contract includes multiple promised goods or services, the Company applies judgment to determine whether promised goods or services are capable of being distinct, and are distinct in the context of the contract. If these criteria are not met, the promised goods or services are accounted for as a combined performance obligation. • Determination of the transaction price — The transaction price is determined based on the consideration that the Company will be entitled to in exchange for transferring goods or services to the customer. In determining the transaction price, the Company considers uncertainties such as historical rates of product returns and/or concessions. • Allocation of the transaction price to the performance obligation(s) in the contract — If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative standalone selling price (“SSP”) basis. The Company determines standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. • Recognition of revenue when, or as, a performance obligation is satisfied — The Company satisfies performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at the time the related performance obligation is satisfied by transferring a promised good or service to a customer. Revenue is recorded net of sales taxes. The following describes the nature of the Company’s primary types of revenue and the revenue recognition policies as they pertain to the types of transactions the Company enters into with its customers. License Revenue License revenue consists of sales of Software Products and Hardware Products. Software Products are sold with either a perpetual license or a term license. License revenue includes the value allocated to license within Software Products subscription contracts. License revenue is recognized at the time of transfer of control, which is generally upon delivery of access to software downloads or shipment, provided that all other revenue recognition criteria have been met. Subscription Revenue Subscription revenue is derived from support and maintenance contracts, the value allocated to support and maintenance within Software Products subscription contracts, and software as a service (“SaaS”) offering contracts. Customers do not have the right to take possession of the cloud-based software. Subscription contracts have terms that are generally either one or three years, but can be up to five years. Subscription revenue is recognized ratably over the term of the contract and any unearned subscription revenue is included in deferred revenue. Professional Services Revenue Professional services revenue is derived primarily from customer fees for optional installation of the Company’s products or training. Generally, the Company recognizes revenue for professional services as the services are rendered. Contract Costs The Company capitalizes contract origination costs that are incremental and recoverable costs of obtaining a contract with a customer. The Company expects that sales commissions and associated payroll taxes and third-party referral fees related to customer contracts are both incremental and recoverable. The contract origination costs are capitalized and amortized to sales and marketing expense when the related performance obligations are met. Incremental contract origination costs relating to products are expensed as the related products are delivered. Incremental contract origination costs relating to term contracts are capitalized and amortized over either the contractual performance period or on a straight-line basis over the average customer life of five years , depending on whether the costs relate to a specific term contract or the customer relationship. The Company determines its average customer life by taking into consideration its customer contracts, technology, and other factors. Capitalized costs are periodically reviewed for impairment. Capitalized contract costs were $36.0 million and $35.9 million as of December 31, 2019 and December 31, 2018 , respectively. For the years ended December 31, 2019 , 2018 , and 2017 , amortization expense for the contract costs was $14.4 million , $14.9 million , and $11.4 million , respectively. There were no impairment losses in relation to the costs capitalized for the years ended December 31, 2019 , 2018 , and 2017 . Revenue from Contracts with Customers Contract Assets and Contract Liabilities A contract asset is a right to consideration in exchange for products or services that the Company has transferred to a customer when that right is conditional and is not just subject to the passage of time. The Company has no material contract assets. A receivable will be recorded on the consolidated balance sheets when the Company has unconditional rights to consideration. A contract liability is an obligation to transfer products or services for which the Company has received consideration, or for which an amount of consideration is due from the customer. Contract liabilities include customer deposits under non-cancelable contracts and current and non-current deferred revenue balances. The Company’s contract balances are reported in a net contract asset or liability position on a contract-by-contract basis at the end of each reporting period. Significant changes in contract liabilities during the periods presented are as follows (in thousands): Contract Liabilities Balance as of December 31, 2017 135,867 Additions 327,650 Assumed in a business combination 6,297 Gross revenue recognized (297,783 ) Balance as of December 31, 2018 172,031 Additions 353,601 Gross revenue recognized (336,725 ) Balance as of December 31, 2019 $ 188,907 During the years ended December 31, 2019 and 2018 , the Company recognized revenue of $101.9 million and $80.0 million that was included in the contract liabilities balance as of December 31, 2018 and 2017 , respectively. Contract modifications entered into during the year ended December 31, 2019 and 2018 did not have a significant impact on the Company’s contract assets or contract liabilities. Performance Obligations The majority of the contracted but not invoiced performance obligations are subject to cancellation terms. Revenue allocated to remaining performance obligations represent contracted revenue that has not yet been recognized (“contracted not recognized”), which includes deferred revenue, certain customer deposits, and non-cancelable amounts that will be invoiced and recognized as revenue in future periods and excludes performance obligations that are subject to cancellation terms. Contracted not recognized revenue was $188.9 million as of December 31, 2019 , of which the Company expects to recognize approximately 60% of the revenue over the next 12 months and the remainder thereafter. Practical Expedients The Company does not disclose the value of consideration associated with unsatisfied or partially unsatisfied performance obligations for contracts for which the Company recognizes revenue at the amount to which it will have the right to invoice for services performed. The Company also reflects the aggregate effect of all modifications to a contract that occurred before the earliest period presented in the current period’s financial statements instead of retrospectively restating contracts for all previous contract modifications. Disaggregation of Revenue The following table depicts the disaggregation of revenue according to revenue type and is consistent with how the Company evaluates its financial performance (in thousands): Year Ended December 31, 2019 2018 2017 Revenue: License Software products Perpetual license $ 104,521 $ 106,978 $ 49,405 Term license 23,459 — — Hardware products 47,135 55,689 75,943 Subscription SaaS 22 — — Support and maintenance 142,755 118,572 86,691 Professional services 18,909 16,412 12,365 Total revenue $ 336,801 $ 297,651 $ 224,404

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
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): December 31, 2019 December 31, 2018 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents: Cash $ 62,188 $ — $ — $ 46,017 $ — $ — Money market accounts 6,842 — — 20,878 — — Total cash and cash equivalents 69,030 — — 66,895 — — Marketable securities: Commercial paper — 1,998 — — 3,991 — Corporate debt securities — 24,168 — — 35,640 — U.S. government securities — 3,015 — — 8,001 — Total marketable securities — 29,181 — — 47,632 — Restricted cash (current and non-current) 2,561 — — 2,117 — — Total financial assets $ 71,591 $ 29,181 $ — $ 69,012 $ 47,632 $ —

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities The following table summarizes the unrealized gains and losses, and fair value of the Company’s marketable securities as of December 31, 2019 and 2018 (in thousands): December 31, 2019 December 31, 2018 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Amortized Cost Unrealized Gains Unrealized Losses Fair Value Marketable securities: Available-for-sale: Commercial paper $ 1,998 $ — $ — $ 1,998 $ 3,991 $ — $ — $ 3,991 Corporate debt securities 24,122 46 — 24,168 35,730 — (90 ) 35,640 U.S. government securities 3,012 3 — 3,015 8,012 — (11 ) 8,001 Total marketable securities $ 29,132 $ 49 $ — $ 29,181 $ 47,733 $ — $ (101 ) $ 47,632 The following table summarizes the amortized cost and fair value of the Company’s available-for-sale securities as of December 31, 2019 and 2018 , by the contractual maturity date (in thousands): 2019 2018 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 29,132 $ 29,181 $ 47,733 $ 47,632 Total $ 29,132 $ 29,181 $ 47,733 $ 47,632 The Company had no marketable securities in unrealized loss position and no other-than-temporary impairments for marketable securities as of December 31, 2019 . The Company had 13 marketable securities in unrealized loss positions as of December 31, 2018 . For individual marketable securities that were in an unrealized loss position as of December 31, 2018 , the fair value and gross unrealized loss for these securities aggregated by investment category and length of time in an unrealized loss position are presented in the following tables (in thousands): December 31, 2018 Less Than 12 Months Greater Than 12 Months Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Corporate debt securities $ 4,020 $ (3 ) $ 31,620 $ (87 ) $ 35,640 $ (90 ) U.S. government securities — — 8,001 (11 ) 8,001 (11 ) Total $ 4,020 $ (3 ) $ 39,621 $ (98 ) $ 43,641 $ (101 ) Unrealized losses related to these marketable securities are due to interest rate fluctuations as opposed to credit quality. In addition, the Company does not intend to sell and it is not likely that the Company would be required to sell these marketable securities before recovery of their amortized cost basis, which may be at maturity. As a result, there are no other-than-temporary impairments for these marketable securities at December 31, 2018 .

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): December 31, 2019 2018 Leasehold improvements $ 19,883 $ 19,832 Computer, equipment and software 16,712 14,591 Furniture and fixtures 4,586 4,361 Demonstration units 3,805 3,262 Total property and equipment 44,986 42,046 Less: accumulated depreciation (21,151 ) (17,697 ) Total property and equipment, net $ 23,835 $ 24,349 Depreciation expense related to property and equipment for the years ended December 31, 2019 , 2018 , and 2017 was approximately $8.6 million , $7.5 million and $6.1 million , respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases Effective January 1, 2019, the Company adopted Topic 842 using the transition method to apply the new lease standard at the adoption date and recognized a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The adoption had a material impact on the total assets and total liabilities reported on the Company’s consolidated balance sheets resulting in an increase in long-term assets and total liabilities of approximately $20.3 million as of January 1, 2019. The Company has operating leases for corporate offices, vehicles, and office equipment. The leases have remaining lease terms of up to seven years , some of which may include options to extend the leases for up to five years . Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company elected to combine the lease components (e.g., fixed payments including rent, real estate taxes, and insurance costs) and the non-lease components (e.g., common-area maintenance costs) for all classes of underlying assets, and to not reassess prior conclusions related to contracts containing leases, lease classification, and initial direct costs. The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use assets, current operating lease liabilities, and non-current operating lease liabilities on the Company’s consolidated balance sheets. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate, the Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. For leases that commenced prior to January 1, 2019, the Company uses the incremental borrowing rate as of January 1, 2019 to determine the present value of future payments on those leases. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. The lease terms may include options to extend the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. During the year ended December 31, 2019 , the Company recognized operating lease cost of $9.4 million , which included short-term leases and variable lease costs that were immaterial. Maturities of lease liabilities as of December 31, 2019 were as follows (in thousands): Years Ending December 31, Operating Leases 2020 $ 8,280 2021 7,773 2022 7,455 2023 7,384 2024 7,315 Thereafter 8,326 Total lease payments $ 46,533 Less: Imputed interest 8,568 Present value of lease liabilities $ 37,965 Lease Term and Discount Rate December 31, 2019 Operating leases Weighted-average remaining lease term 6 years Weighted-average discount rate 7.1 % Other information (in thousands) December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 6,565 Leased assets obtained in exchange for new operating lease liabilities $ 15,159 Supplemental Information for Comparative Periods As of December 31, 2018 , prior to the adoption of Topic 842, future minimum lease payments by fiscal year under non-cancelable leases are as follows (in thousands): Years Ending December 31, Operating 2019 $ 5,551 2020 4,188 2021 4,307 2022 4,435 2023 4,461 2024 and thereafter 11,933 Total $ 34,875 Rent expense was approximately $6.4 million and $5.6 million for the years ended December 31, 2018 and 2017

Acquisitions, Goodwill, and Int

Acquisitions, Goodwill, and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions, Goodwill, and Intangible Assets	Acquisitions, Goodwill, and Intangible Assets Bullguard Israel Ltd. On October 2, 2019, the Company entered into a definitive Asset Purchase Agreement to acquire certain assets from Bullguard Israel Ltd., an IoT security company, for a total purchase price of $10.3 million in cash (the “Bullguard Acquisition”). The Bullguard Acquisition has been accounted for as a business combination and is intended to support and accelerate the Company’s development of cloud-delivered products as part of its end-to-end device visibility and control platform. The purchase price was allocated as follows (in thousands): Amount Intangible assets - Developed technology $ 3,790 Goodwill 6,481 Total purchase price allocation $ 10,271 The weighted average useful life of the developed technology acquired was four years . The goodwill recognized in connection with the acquisition is primarily attributable to anticipated synergies from future growth and is not expected to be deductible for tax purposes. Acquisition transaction costs recognized in general and administrative expense in the Company’s consolidated statements of operations during the year ended December 31, 2019 were immaterial. SecurityMatters B.V. On November 7, 2018, the Company acquired 100% of the equity interests of SecurityMatters B.V. (“SecurityMatters” or “Forescout Technologies, B.V.”), a privately-held entity that develops cybersecurity solutions for the operational technology market, through a share purchase agreement (the “Purchase Agreement”) in exchange for cash consideration (the “Acquisition”). This Acquisition has been accounted for as a business combination and is intended to enhance the Company’s market-leading solutions with deeper visibility into the operational technology network stack. The total consideration transferred as part of the closing of the Acquisition for all of the vested and outstanding equity interests of SecurityMatters consisted of cash payments (adjusted for customary closing adjustments) of $109.3 million (the “Purchase Consideration”). There were no other components of Purchase Consideration other than cash payments. Also, as part of the Purchase Agreement, the Company agreed to pay cash on the closing date of the Acquisition of $6.2 million to be held by a third-party escrow agent and to be released to a continuing employee of SecurityMatters (the “Holdback Amounts”). At closing, such Holdback Amounts were recorded as prepaid expenses and other current assets for the current portion and other assets for the non-current portion, and released or will be released at future dates following the one and two-year anniversaries of the Acquisition in exchange for future employee services to the Company (assuming the employee provides the required service). In addition, as part of the Purchase Agreement, the Company agreed to pay cash on future dates of $1.2 million to continuing employees of SecurityMatters in exchange for such employees’ equity awards that were unvested as of the closing of the Acquisition. Such cash payments were paid on future dates that are consistent with the original SecurityMatters equity awards’ vesting terms (assuming the employees provide employee services to the Company through such future dates). Such amounts were not included as Purchase Consideration, but instead will be recognized as post-combination compensation expense over the period the employees provide the required services. Also in connection with the Acquisition, the Company issued RSUs with a grant date fair value of $5.9 million to continuing employees of SecurityMatters in exchange for future employee services to the Company, which vest annually over four years from the grant date. Such amounts are recorded as post-combination compensation expense over the period the employees provide the requisite service. Additionally, the Company recognized $2.7 million of acquisition transaction costs as general and administrative expense in the Company’s consolidated statements of operations during the year ended December 31, 2018. The Purchase Consideration of $109.3 million was allocated as follows (in thousands): Amount Net tangible assets acquired $ 686 Intangible assets 19,500 Deferred tax liabilities, net (3,486 ) Goodwill 92,648 Total purchase price allocation $ 109,348 The following table sets forth the components of identifiable intangible assets acquired and their estimated useful lives as of the date of acquisition (in thousands, except useful life): Intangible Assets Cost Weighted Average Useful Life (in years) Developed technology $ 13,300 7.0 Customer relationships 6,200 5.0 Total intangible assets acquired $ 19,500 6.4 Goodwill represents the excess of the preliminary estimated Purchase Consideration over the preliminary estimates of the fair value of the net tangible and intangible assets acquired and has been allocated to the Company’s one operating segment. Goodwill is primarily attributable to expected post-acquisition synergies from integrating SecurityMatters’ technology into the Company’s security solutions and product offerings and cross-selling opportunities. None of the goodwill recorded is deductible for income tax purposes. The results of operations of SecurityMatters have been included in the Company’s consolidated statements of operations from the acquisition date. Pro forma results of operations for the transaction have not been presented as they were not material to the consolidated statements of operations. Effective July 1, 2019, all of the intellectual property from Forescout Technologies, B.V. was transferred to the Company. Goodwill and Acquired Intangible Assets There was no goodwill related to acquisitions as of December 31, 2017 and in prior periods. The changes in the carrying amount of goodwill are as follows (in thousands): Amount Balance as of December 31, 2017 $ — Goodwill acquired 92,648 Foreign currency translation adjustments (166 ) Balance as of December 31, 2018 92,482 Goodwill acquired 6,481 Goodwill adjustments (565 ) Foreign currency translation adjustments (380 ) Balance as of December 31, 2019 $ 98,018 Intangible assets subject to amortization realized from acquisitions are as follows (in thousands): December 31, 2019 December 31, 2018 Cost Accumulated Amortization Foreign Currency Translation Adjustments Net Cost Accumulated Amortization Foreign Currency Translation Adjustments Net Developed technology $ 17,090 $ (2,392 ) $ (85 ) $ 14,613 $ 13,300 $ (280 ) $ (24 ) $ 12,996 Customer relationships 6,200 (1,405 ) (41 ) 4,754 6,200 (183 ) (11 ) 6,006 $ 23,290 $ (3,797 ) $ (126 ) $ 19,367 $ 19,500 $ (463 ) $ (35 ) $ 19,002 Amortization expense of intangible assets for the years ended December 31, 2019 and 2018 was $3.3 million and $0.5 million , respectively, which was recognized in the consolidated statements of operations, within product cost of revenue, research and development expenses, and sales and marketing expenses. There was no amortization expense of intangible assets during the year ended December 31, 2017 . The expected future annual amortization expense of intangible assets as of December 31, 2019 is presented below (in thousands): Year Ending December 31, Amount 2020 $ 4,057 2021 4,057 2022 4,057 2023 3,667 2024 and thereafter 3,529 Total $ 19,367

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Contract Manufacturer Commitments As of December 31, 2019 , the Company had contract manufacturer commitments of $7.0 million to purchase components and products from the Company’s third-party contract manufacturer. The contract manufacturer commitments result from the Company’s contractual obligation to order or build inventory in advance of anticipated sales. Purchase Obligations As of December 31, 2019 , the Company had purchase obligations of $4.6 million primarily related to non-cancelable license obligations for software licenses. Litigation The Company is a party to various legal proceedings and claims which arise in the ordinary course of business. The Company records a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. If the Company determines that a loss is possible and a range of the loss can be reasonably estimated, the range of the possible loss is disclosed. On January 2, 2020, a complaint was filed in the United States District Court, Northern District of California, by Christopher L. Sayce, individually, and on behalf of all others similarly situated, against the Company and two of its executive officers, for violations of the federal securities laws following the Company’s pre-earnings release announcement on October 10, 2019. The complaint, which purports to be brought on behalf of a class of purchasers of the Company’s securities during the period from February 7, 2019 through October 9, 2019, seeks to recover damages for such violations and to pursue remedies under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934. The claim does not state a value for potential damages. Based on the Company’s preliminary review, the Company believes the claim to be without merit and plans to vigorously defend itself to the maximum extent allowed by the law. Indemnification The Company enters into indemnification provisions in its standard sales contracts with its customers in which it agrees to defend its channel partners and end-customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and the responsibility to pay judgments entered on such claims. In addition, we indemnify our officers, directors and certain key employees while they are serving in good faith in their respective capacities. To date, there have been no claims under any indemnification provisions.

Debt Agreements

Debt Agreements	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt Agreements	Debt Agreements On December 22, 2016, the Company amended its amended and restated loan and security agreement, which was originally entered into in May 2009 (the “Amended and Restated 2009 Loan and Security Agreement”) to increase the maximum amount of credit available for borrowing under the revolving line of credit to 80% of qualified accounts receivable up to $40.0 million . Additionally, the Company borrowed $30.0 million under the Amended and Restated 2009 Loan and Security Agreement, which carries a maturity date of December 2020 . The combined outstanding balances of the revolving line of credit and the term loan cannot exceed $40.0 million . The agreement is subject to the Company maintaining an adjusted quick ratio of 1.25 . The agreement requires equal monthly installments of principal of $625,000 and monthly interest payments at a fixed interest rate per annum of 3.25% . Concurrent with the final monthly installment payment on the maturity date in December 2020, the Company is required to pay an additional payment of $825,000 . On April 4, 2019, the Company signed a Second Amended and Restated Loan and Security Agreement to extend the maturity period of the revolving line of credit by two years to March 31, 2021 and amend the borrowing base and interest of the revolving line of credit. The amortization expense related to the total discount of the Company’s debt for the years ended December 31, 2019 , 2018 , and 2017 was $0.2 million , $0.3 million , and $0.3 million , respectively. As of December 31, 2019 and 2018 , there was no outstanding balance under the revolving line of credit. The following table presents the carrying value of the Company’s notes payable (in thousands): December 31, 2019 2018 Principal amount of notes payable $ 8,325 $ 15,825 Unamortized debt discount (77 ) (246 ) Net carrying amount of notes payable 8,248 15,579 Less current portion (8,248 ) (7,331 ) Non-current portion of notes payable $ — $ 8,248 The Amended and Restated 2009 Loan and Security Agreement and the Second Amended and Restated Loan and Security Agreement provide certain financial-related covenants, among others, relating to delivery of audited financial statements to the lenders. The Company was in compliance with respect to all financial-related covenants under its loan agreements as of December 31, 2019 and 2018 . As of December 31, 2019 , the future principal payments on the Company’s notes payable was $8.3 million

Common Stock and Stockholders'

Common Stock and Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Common Stock and Stockholders' Equity	Common Stock and Stockholders’ Equity Redeemable Convertible Preferred Stock Upon the closing of the IPO in October 2017, all shares of the Company's then-outstanding redeemable convertible preferred stock automatically converted into 25,370,616 shares of common stock, including 582,254 additional shares issuable upon conversion of our Series G redeemable convertible preferred stock based on the initial public offering price of $22.00 per share. As of December 31, 2019 and 2018 , there were no shares of redeemable convertible preferred stock issued and outstanding. Redeemable Convertible Preferred Stock Warrants Concurrent with the closing of the IPO, all shares of outstanding redeemable convertible preferred stock warrants were either exercised or converted to common stock warrants. 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 of exercise was $25.12 , which resulted in 224,691 shares being issued by the Company. Common Stock Warrants No common stock warrants were exercised during the year ended December 31, 2019 . During the year ended December 31, 2018 , 83,163 common stock warrants were exercised. 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 per share at the time exercise was $33.36 , which resulted in 66,661 shares being issued by the Company for the warrants exercised during the year ended December 31, 2018 . As of December 31, 2019 , 74 common stock warrants remained outstanding and exercisable. Common Stock As of December 31, 2019 and 2018 , 4.1 million shares and 3.9 million shares of our common stock were reserved for future grants under the 2017 Plan, respectively. As of December 31, 2019 , common stock reserved, on an as-if converted basis for issuance are as follows (in thousands): December 31, 2019 Reserved for future issuance under equity award plans 4,107 Common stock options outstanding 3,066 Restricted stock units outstanding 6,391 Total common stock reserved for issuance 13,564 Stock Option and Incentive Plan The 2000 Stock Option and Incentive Plan (the “2000 Plan”) allows for the issuance of stock options and RSUs to employees, non-employees and directors. The Plan provides for incentive stock options to be granted to employees at an exercise price at least equal to 100% of the fair value at the grant date as determined by the Company’s Board of Directors. If a stock-based award is issued to an executive officer that owns more than 10% of the Company’s outstanding common stock, the exercise price will be 110% of the fair market value. The Plan also provides for non-qualified stock options to be issued to employees, non-employees and directors. Options granted generally have a maximum term of 10 years from grant date, allow for early exercise unless otherwise designated by the Board of Directors at the time of grant. Stock options and RSUs generally vest over a four -year period. In October 2017, the Company’s stockholders approved the Company’s 2017 Equity Incentive Plan (the “2017 Plan”). The 2017 Plan provides for the grant of incentive stock options, non-statutory 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 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 lesser 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. Prior to the IPO, options granted allowed for early exercise unless otherwise designated by the Board of Directors at the time of grant. The Company had no early exercise liability as at December 31, 2019 . The Company had an early exercise liability of approximately $0.4 million as at December 31, 2018 . Including early exercises, the Company has 48,063,761 and 43,450,819 shares of legally outstanding common stock as at December 31, 2019 and 2018 , respectively. 2017 Employee Stock Purchase Plan In October 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “ESPP”). 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. The Company’s ESPP provides for consecutive, 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 following the closing of the IPO, and will end on the first trading day on May 18, 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. During the year ended December 31, 2019 , 379,306 shares of common stock were purchased under the ESPP at a weighted-average exercise price of $24.23 per share, resulting in cash proceeds of $9.2 million . The Company selected the Black-Scholes option-pricing model as the method for determining the estimated fair value for the Company’s ESPP. As of December 31, 2019 , total unrecognized compensation cost related to the ESPP was $1.3 million , which will be amortized over a period of 0.4 years. As of December 31, 2019 , 848,345 shares of our common stock were reserved for future sales under the 2017 ESPP Plan. Stock Option Activity The following table summarizes option activity under the Plan and related information (in thousands, except per share and contractual life amounts): Options Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2017 9,314 $ 10.63 7.2 $ 198,012 Granted 44 $ 30.81 Exercised (2,979 ) $ 8.13 Forfeited (366 ) $ 16.59 Balance—December 31, 2018 6,013 $ 11.65 6.4 $ 86,624 Exercised (2,744 ) $ 10.41 Forfeited (203 ) $ 18.01 Balance—December 31, 2019 3,066 $ 12.33 5.6 $ 62,759 Options vested and exercisable—December 31, 2019 2,790 $ 11.55 5.4 $ 59,282 No stock option awards were granted for the year ended December 31, 2019 . The weighted-average fair value per share for all options granted was $14.95 , and $9.79 for the years ended December 31, 2018 and 2017 , respectively. The aggregate intrinsic value of employee options exercised was $72.3 million , $71.9 million , and $4.4 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. The aggregate intrinsic value represents the difference between the Company’s estimated fair value of its common stock and the exercise price of the outstanding options. As of December 31, 2019 , total unrecognized compensation cost related to unvested options was $2.5 million , net of estimated forfeitures, which was expected to be amortized over a weighted-average period of approximately 1.1 years. Restricted Stock Units (“RSUs”) and Performance Based Stock Units (“PSUs”) The following table summarizes RSU and PSU activity under the Plan and related information (in thousands, except per share and contractual life amounts): RSUs and PSUs Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2017 4,216 $ 20.57 1.7 $ 134,448 Granted 3,354 $ 30.94 Released (1,607 ) $ 14.78 Forfeited (254 ) $ 26.80 Balance—December 31, 2018 5,709 $ 28.01 1.8 $ 148,389 Granted 3,145 $ 34.86 Released (1,609 ) $ 26.77 Forfeited (854 ) $ 30.45 Balance—December 31, 2019 6,391 $ 31.37 1.7 $ 209,621 Beginning in 2019, the Company issued PSUs to select executives under the 2017 Plan. The majority of the PSUs vest over a period of four years from the date of grant subject to both the continued employment of the participant with the Company and the achievement of one or more pre-established financial performance goals. Stock-based compensation expense for PSUs is recognized using the accelerated attribution method over the requisite service periods when it is probable that the performance condition will be achieved. During the year ended December 31, 2019 , the Company entered into a Separation and Release Agreement with a former employee in which the Company agreed to grant future RSUs amounting to $3.0 million in exchange for consulting service during a two -year period. The Company will issue the grant upon acceptance of the deliverables at the end of each year of the consulting period. The Company accrued the stock-based compensation expense arising from this transaction over the requisite service period with a credit to accrued expenses. The accrued expenses will be reclassified to additional paid in capital upon the issuance of the grant. For the year ended December 31, 2019 , the stock-based compensation expense related to this transaction was included in sales and marketing expense in the accompanying consolidated statements of operations and was immaterial. On June 5, 2019, the Company granted a number of PSUs with a grant date fair value of $2.1 million to one of the members of the board of directors of the Company as part of a consulting agreement. Refer to Note 15 for detailed discussion of the agreement. The aggregate fair value, as of the respective vesting dates, of RSUs and PSUs vested during the years ended December 31, 2019 and 2018 was $58.9 million and $51.2 million , respectively. There were no RSUs and PSUs vested during the year ended December 31, 2017. As of December 31, 2019 , total unrecognized compensation cost related to unvested RSUs and PSUs was $155.4 million , which was expected to be amortized over a weighted-average period of approximately 2.7 years. Stock-Based Compensation Stock-based compensation expense for both employees and non-employees included in the accompanying consolidated statements of operations is as follows (in thousands): Year Ended December 31, 2019 2018 2017 Cost of revenue: License $ 346 $ 253 $ 103 Subscription 1,851 1,517 1,089 Professional services 1,730 1,498 1,202 Research and development 12,303 10,161 6,213 Sales and marketing 25,698 24,999 14,451 General and administrative 13,522 15,069 19,538 Total $ 55,450 $ 53,497 $ 42,596 Prior to the IPO, certain employees and advisors have been granted stock options with vesting subject to a future liquidity event. Upon the liquidity event, these stock options became fully exercisable, and all of the associated stock-based compensation expense was recognized. Upon the closing of the Company’s IPO on October 31, 2017 , the Company recognized stock-based compensation expense of approximately $21.2 million related to these performance-based stock options and RSUs. During the year ended December 31, 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), $6.5 million of which was recorded by the Company during the three months ended December 31, 2017. The remaining $1.1 million was recorded by the Company in the year ended December 31, 2018. Determining the Fair Value of Stock Options The fair value of stock option awards granted to employees and ESPP purchase rights are estimated using the Black-Scholes option-pricing model. The key assumptions within the model are described as follows: Fair Value of Common Stock Prior to the Company’s IPO, the Company’s Board of Directors considered numerous objective and subjective factors to determine the fair value of its common stock. These factors included, but were not limited to (i) contemporaneous third-party valuations of common stock; (ii) the rights and preferences of redeemable convertible preferred stock relative to common stock; (iii) the lack of marketability of common stock; (iv) developments in the business; and (v) the likelihood of achieving a liquidity event, such as an initial public offering or sale of the Company, given prevailing market conditions. Subsequent to its IPO, the Company uses the market closing price for its common stock as reported on the NASDAQ Global Select Market on the date of grant. Risk-Free Interest Rate The risk-free interest rate is based on the rate for a U.S. Treasury zero-coupon issue with a term that approximates the expected life of the option on the date of grant. Expected Term The expected term represents the period that stock-based awards are expected to be outstanding. The expected term is calculated using the simplified method for stock options issued at-the-money. For stock options that have been issued out-of-the-money, the expected term was determined by calculating the midpoint of the simplified method and the contractual life of the option of 10 years , as neither historical experience nor other relevant data was available to estimate the future exercise behavior of out-of-the money stock options. The Company uses the remaining contractual life as the expected term for non-employee awards. Volatility The expected volatility is based on the average historic price volatility for the Company’s publicly traded industry peers based on daily price observations over a period equivalent to the expected term of stock-based awards. The historical volatility data of a peer group is used as there is insufficient trading history for the Company’s common stock. Dividend Yield The Company has never paid dividends and at present, does not expect to pay dividends in the foreseeable future. The assumptions used to determine the grant date fair value of employee stock options and ESPP purchase rights for the periods presented are as follows: Year Ended December 31, 2019 2018 2017 Employee Stock Options Fair value of common stock $— $29.92 – $30.97 $16.73 – $31.16 Risk-free interest rate —% 2.4% – 2.8% 1.9% – 2.2% Expected term (in years) 0 6.1 6.0 – 6.1 Volatility —% 48% 46% – 49% Dividend yield —% —% —% Employee Stock Purchase Plan Fair value of common stock $33.69 – $35.03 $24.65 – $31.00 $25.12 Risk-free interest rate 1.6% – 2.4% 2.14% – 2.52% 1.4% Expected term (in years) 0.5 0.5 0.5 Volatility 35% – 40% 30% – 43% 30% Dividend yield —% —% —%

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of loss before provision for income taxes are as follows (in thousands): Year Ended December 31, 2019 2018 2017 Domestic $ (108,234 ) $ (85,252 ) $ (82,292 ) Foreign 8,420 13,361 3,411 Total $ (99,814 ) $ (71,891 ) $ (78,881 ) The provision for income taxes consists of the following (in thousands): Year Ended December 31, 2019 2018 2017 Current Federal $ 14 $ 1 $ 17 State 93 56 50 Foreign 23,857 3,263 1,788 Total current 23,964 3,320 1,855 Deferred Foreign (5,243 ) (375 ) (16 ) Total deferred $ (5,243 ) $ (375 ) $ (16 ) Total $ 18,721 $ 2,945 $ 1,839 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes and tax effects of net operating loss and credit carryforwards. Significant components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2019 2018 Deferred tax assets: Federal and state net operating losses $ 91,529 $ 59,803 Research/other credits 3,898 2,913 Non-deductible and accrued expenses 2,780 4,756 Deferred revenue 16,576 14,040 Property and equipment 430 506 Stock-based compensation 10,363 10,323 Lease liability 6,560 — Other 705 1,024 Gross deferred tax assets 132,841 93,365 Valuation allowance (112,882 ) (83,376 ) Net deferred tax assets 19,959 9,989 Deferred tax liabilities: Acquired intangible assets (3,807 ) (4,117 ) Right of use asset (4,738 ) — Deferred commission (8,684 ) (8,691 ) Others (27 ) (116 ) Net deferred tax liabilities (17,256 ) (12,924 ) Total $ 2,703 $ (2,935 ) Reconciliation of the statutory federal income tax to the Company’s effective tax (in thousands): Year Ended December 31, 2019 2018 2017 Tax at federal statutory rate $ (20,972 ) $ (15,097 ) $ (30,385 ) State, net of federal benefit 92 61 60 Meals and entertainment disallowance 835 799 365 Stock-based compensation (7,852 ) (6,215 ) 4,097 Non-deductible warrant expenses — — 272 Tax Reform federal rate change — — 36,460 Impact of intangible property transfer 20,551 — — Change in valuation allowance 25,874 23,929 (10,512 ) Other 193 (532 ) 1,482 Total $ 18,721 $ 2,945 $ 1,839 A valuation allowance has been provided to reduce the deferred tax asset to an amount management believes is more likely than not to be realized. The valuation allowance increased by $29.5 million and $29.1 million for the years ended December 31, 2019 and 2018 , respectively. As of December 31, 2019 , the Company had net operating loss carryforwards for federal income tax purposes of approximately $378.6 million , which begin to expire in 2021 if not utilized. The Company also has California net operating loss carryforwards of approximately $36.6 million , which begin to expire in 2028 if not utilized. The Company also has other state net operating loss carryforwards of approximately $168.1 million , which begin to expire in 2020 if not utilized. The Company has federal, California, and Texas research and development credit carryforwards of $2.4 million , $1.5 million , and $0.3 million respectively. The federal research and development credits will begin to expire in 2035, if not utilized. California research and development credits can be carried forward indefinitely. Utilization of the Company’s net operating loss carryforwards may be subject to substantial annual limitation due to the ownership change limitations provided by the Internal Revenue Code and similar state provisions. Such a limitation could result in the expiration of the net operating loss carryforwards before utilization. The Company provides U.S. income taxes on the earnings of foreign subsidiaries, unless the subsidiaries’ earnings are considered indefinitely reinvested outside the United States. As of December 31, 2019 , there was no income tax expense accrual related to undistributed earnings from its foreign subsidiaries as they are considered indefinitely reinvested. The Company has not determined the unrecognized deferred tax liability associated with un-remitted foreign earnings because it is not practicable to do so. Uncertain Tax Positions For benefits to be realized, a tax position must be more likely than not to be sustained upon examination. The amount recognized is measured as the largest amount of benefit that is greater than 50 percent likely of being realized upon settlement. As a result of the implementation of these provisions, the Company did not recognize any adjustments to retained earnings for uncertain tax positions. A reconciliation of the gross unrecognized tax benefit is as follows (in thousands): Year Ended December 31, 2019 2018 2017 Unrecognized tax benefits at the beginning of the period $ 1,267 $ 1,727 $ 1,050 Additions for tax positions taken in prior years 64 104 248 Additions for tax positions taken in current year 20,816 195 845 Reductions for tax positions taken in prior years — (759 ) — Settlements with taxing authorities — — (416 ) Statute of limitation expirations (104 ) — — Unrecognized tax benefits at the end of the period $ 22,043 $ 1,267 $ 1,727 It is the Company’s policy to recognize interest and penalties related to income tax matters in income tax expense. During the years ended December 31, 2019 , 2018 , and 2017 , the Company did not recognize any significant accrued interest and penalties related to uncertain tax positions. For the year ended December 31, 2019 , the Company recorded an accrual for uncertain tax position of $20.8 million related to the completion of an intra-group transfer of certain intellectual property rights from the Netherlands to the United States. The Company is subject to federal income tax as well as income tax in multiple state and foreign jurisdictions. Due to the Company’s net operating loss carryforwards, all tax years since inception remain subject to examination for United States federal tax returns, and fiscal year 2016 remains subject to examination for Israel. There are tax years which remain subject to examination in various other jurisdictions that are not material to the Company’s financial statements. We expect the amount of unrecognized tax benefits to be reduced within the next 12 months by at least $0.9 million as a result of settlement with tax authorities. On April 22, 2018, the Supreme Court of Israel ruled to uphold a decision for stock based compensation to be included within Israeli entities’ transfer pricing reimbursement arrangements. As a result, the Company changed its tax return filing position for fiscal year 2018 and the uncertain tax position associated with this liability decreased by approximately $0.4 million , there was a corresponding increase to current income tax payable included in accrued expenses. The total amount of unrecognized tax benefits that, if recognized, would impact the effective tax rate would be $21.3 million , $1.1 million , and $1.4 million for the years ended December 31, 2019 , 2018 , and 2017 .

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2019
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. 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 per share amounts): Year Ended December 31, 2019 2018 2017 Net loss $ (118,535 ) $ (74,836 ) $ (80,720 ) Deemed dividend on the conversion of Series G redeemable convertible preferred stock — — 12,810 Net loss attributable to common stockholders $ (118,535 ) $ (74,836 ) $ (93,530 ) Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted 45,957 40,980 11,405 Net loss per share attributable to common stockholders, basic and diluted $ (2.58 ) $ (1.83 ) $ (8.20 ) 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 (in thousands). Year Ended December 31, 2019 2018 2017 Options to purchase common stock 3,066 6,013 9,314 Unvested early exercised common shares — 47 146 Unvested restricted stock units 6,391 5,709 4,216 Shares estimated under ESPP 196 233 221 Warrants to purchase common stock — — 83

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Israeli labor laws and agreements require the Company’s Israeli subsidiary to make severance payments to retired or dismissed Israeli employees, as well as to employees leaving employment under certain other circumstances. The Company’s severance obligations to employees are measured based upon length of service and latest monthly salary amount. The Company has recorded a non-current liability of $3.0 million and $2.5 million as of December 31, 2019 and 2018 , respectively, for the estimated amount of accrued severance benefits in other liabilities in the accompanying consolidated balance sheet. The current portion of the liability was immaterial as of December 31, 2019 and 2018 . The deposits are held with a severance pay fund in order to fund the obligation, which totaled $2.4 million and $2.0 million as of December 31, 2019 and 2018 , respectively, and are recorded as a non-current asset in other assets in the accompanying consolidated balance sheets. The current portion of the deposit was immaterial as of December 31, 2019 and 2018. A 401(k) tax-deferred savings plan (the “401(k) Plan”) was established that covers substantially all of the Company’s U.S. employees. The 401(k) plan permits participants to make contributions by salary deduction pursuant to Section 401(k) of the Internal Revenue Code. The Company is responsible for administrative costs of the 401(k) Plan. The Company provided for a match of 50% of the first 6% of an eligible employee’s compensation contributed, up to a maximum matching dollar amount of $2,000 for a year. Matching contributions under the 401(k) Plan are 100% vested when made. Pre-tax 401(k) and post-tax Roth 401(k) contributions are allocated to each participant’s individual account and are then invested in selected investment alternatives according to the participants’ directions. The 401(k) Plan is intended to qualify under Sections 401(a) and 501(a) of the Code. As a tax-qualified retirement plan, pre-tax contributions are not taxable to the employees until distributed from the 401(k) Plan, and post-tax contributions are not exempt from taxes at the time of contribution but the earnings accumulated are tax-free and are not taxable upon distribution. All contributions are deductible by the Company when made. The Company’s contributions to the 401(k) Plan were $1.4 million , $1.3 million , and $1.1 million for the years ended December 31, 2019 , 2018 , and 2017

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information The Company’s business is conducted globally. The Company’s chief operating decision maker is the Chief Executive Officer who reviews financial information presented on a consolidated basis accompanied by information about 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, there is 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): Year Ended December 31, 2019 2018 2017 Revenue: Americas United States $ 236,878 $ 215,322 $ 165,140 Other Americas 11,267 6,883 6,122 Total Americas 248,145 222,205 171,262 Europe, Middle East, and Africa (“EMEA”) 54,228 52,214 36,664 Asia Pacific and Japan (“APJ”) 34,428 23,232 16,478 Total revenue $ 336,801 $ 297,651 $ 224,404 Long-lived assets, net by geographic area are attributed based on legal entity structure and are as follows (in thousands): December 31, 2019 2018 Long-lived assets, net: United States $ 18,598 $ 18,570 Israel 4,370 5,057 Other 867 722 Total long-lived assets, net $ 23,835 $ 24,349

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Consulting agreement with Night Dragon II, LLC On June 5, 2019, the Company entered into a consulting agreement (the “Consulting Agreement”) with Night Dragon II, LLC (“Night Dragon”). One of the members of the board of directors (“the Board”) of the Company is a principal and the chief executive officer of Night Dragon and will personally provide services to the Company under the Consulting Agreement. Pursuant to the Consulting Agreement, Night Dragon will provide consulting and business development services to the Company, including customer engagement, speaking activities, competitive and market analysis, business development assistance and expertise, and other services as described in the Consulting Agreement. In consideration for the consulting and business development services to the Company, the Board granted the director a number of PSUs with a grant date fair value of $2.1 million . The PSUs will vest on the achievement of certain milestones detailed in the Consulting Agreement, in each case, so long as the Consulting Agreement remains in effect. The term of the Consulting Agreement commenced on June 5, 2019 and will continue for two years or until terminated in accordance with its terms. For the year ended December 31, 2019 , the stock-based compensation expense related to the Consulting Agreement was included in general and administrative expense and was immaterial. The balance of approximately $1.4 million will be recorded over the remaining period. Related party sale In the third quarter of fiscal 2019, the Company entered into an arrangement with a company affiliated with a member of the Company’s Board of Directors for the sale of the Company’s products and services. Specifically, for the year ended December 31, 2019 , the Company recorded license revenue of $1.4 million and subscription revenue of $0.1 million relating to this contract. As of December 31, 2019 , the related amounts receivable and deferred revenue were immaterial and $0.6 million , respectively.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) The following tables set forth selected unaudited quarterly consolidated statements of operations data for each of the eight quarters in the period ended December 31, 2019 . The information for each of these quarters has been prepared on the same basis as the audited annual consolidated financial statements included elsewhere in this report and, in the opinion of management, includes all adjustments, which consist only of normal recurring adjustments, necessary for the fair presentation of the results of operations for these periods in accordance with GAAP. This data should be read in conjunction with our audited consolidated financial statements and related notes included elsewhere in this report. These quarterly operating results are not necessarily indicative of our operating results for a full year or any future period. Three Months Ended December 31, September 30, June 30, March 31, December 31, September 30, June 30, March 31, (In thousands, except per share amounts) Revenue: License $ 48,401 $ 50,203 $ 38,831 $ 37,680 $ 47,482 $ 51,082 $ 34,323 $ 29,780 Subscription 37,586 36,570 34,822 33,799 32,888 30,339 28,986 26,359 Professional services 5,344 4,849 4,627 4,089 4,362 4,207 4,285 3,558 Total revenue 91,331 91,622 78,280 75,568 84,732 85,628 67,594 59,697 Cost of revenue: License (1) 8,180 9,892 5,622 7,607 6,852 8,947 4,919 7,136 Subscription (1) 5,795 5,376 5,599 5,207 4,613 4,069 3,732 3,801 Professional services (1) 7,050 6,429 6,235 6,186 6,021 6,181 6,062 5,549 Total cost of revenue 21,025 21,697 17,456 19,000 17,486 19,197 14,713 16,486 Total gross profit 70,306 69,925 60,824 56,568 67,246 66,431 52,881 43,211 Operating expenses: Research and development (1) 24,302 20,556 19,440 18,497 17,161 15,062 14,803 14,687 Sales and marketing (1) 49,915 51,035 56,173 55,923 50,464 46,098 45,039 42,279 General and administrative (1) 15,649 15,318 15,838 16,213 16,849 13,880 13,260 13,732 Total operating expenses 89,866 86,909 91,451 90,633 84,474 75,040 73,102 70,698 Loss from operations (19,560 ) (16,984 ) (30,627 ) (34,065 ) (17,228 ) (8,609 ) (20,221 ) (27,487 ) Interest expense (105 ) (156 ) (142 ) (93 ) (237 ) (208 ) (225 ) (243 ) Other income, net 422 374 505 617 527 865 513 662 Loss before income taxes (19,243 ) (16,766 ) (30,264 ) (33,541 ) (16,938 ) (7,952 ) (19,933 ) (27,068 ) Income tax provision 767 16,747 496 711 1,010 334 473 1,128 Net loss $ (20,010 ) $ (33,513 ) $ (30,760 ) $ (34,252 ) $ (17,948 ) $ (8,286 ) $ (20,406 ) $ (28,196 ) Net loss per share, basic and diluted $ (0.42 ) $ (0.72 ) $ (0.68 ) $ (0.78 ) $ (0.42 ) $ (0.20 ) $ (0.50 ) $ (0.74 ) Weighted-average shares used to compute net loss per share, basic and diluted 47,511 46,584 45,494 44,196 43,016 42,064 40,457 38,313 _____________________ (1) Includes stock-based compensation expense as follows: Three Months Ended December 31, September 30, June 30, March 31, December 31, September 30, June 30, March 31, (In thousands) Cost of revenue: License $ 99 $ 75 $ 89 $ 83 $ 79 $ 67 $ 54 $ 53 Subscription 484 454 470 443 418 349 371 379 Professional services 493 415 421 401 386 366 352 394 Research and development 3,494 3,040 2,691 3,078 2,688 2,613 2,513 2,347 Sales and marketing 5,684 6,330 7,198 6,486 6,804 6,165 5,850 6,180 General and administrative 3,481 3,508 3,196 3,337 3,578 3,458 3,796 4,237 Total $ 13,735 $ 13,822 $ 14,065 $ 13,828 $ 13,953 $ 13,018 $ 12,936 $ 13,590

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On February 6, 2020, the Company entered into an Agreement and Plan of Merger with Ferrari Group Holdings, L.P., a Delaware limited partnership, and Ferrari Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent. Parent and Merger Sub are affiliates of Advent. The Merger Agreement provides that, subject to the terms and conditions set forth in the Merger Agreement, Merger Sub will merge with and into the Company, with the Company surviving the Merger and becoming a wholly owned subsidiary of Parent. Under the Merger Agreement, at the effective time of the Merger, each issued and outstanding share of the Company’s common stock (except for certain shares specified in the Merger Agreement) will be canceled and automatically converted into the right to receive cash in an amount equal to $33.00 , without interest. Consummation of the Merger is subject to the satisfaction or waiver of customary closing conditions, including (1) approval of the Merger Agreement by the Company’s stockholders; (2) the absence of any law or order restraining, enjoining or otherwise prohibiting the Merger; and (3) the expiration or termination of the waiting period under the United States Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and clearance under the antitrust laws of certain non-United States jurisdictions. The Merger is expected to close in the second fiscal quarter of 2020. Upon consummation of the Merger, the Company’s common stock will no longer be listed on any public market.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
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 (“GAAP”). The Company’s 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.
Use of Estimates	The preparation of financial statements in conformity with GAAP requires management to make use of estimates and assumptions that affect the reported amounts in the 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 best estimate of selling prices for products and related support, the period over which deferred sales commissions are amortized to expense, sales return reserve, accruals, stock-based compensation including the fair value of common stock, redeemable convertible preferred stock warrant liabilities, provision for income taxes, including related reserves, identified intangibles and goodwill, and purchase price allocation of an acquired business. Actual results could differ materially from those estimates.
Reclassifications	Certain amounts in prior periods have been reclassified to conform with current period presentation. In prior years, the Company presented revenue and cost of revenue on the consolidated statements of operations as (i) product and (ii) maintenance and professional services. Under the current presentation of revenue and cost of revenue included in the consolidated statements of operations, product has been retitled as license revenue, and maintenance and professional services is now presented as two separate line items on the consolidated statements of operations as (i) subscription and (ii) professional services. The related prior period financial data were adjusted to reflect the new presentation of the Company’s revenue and cost of revenue. There is no impact on total revenue and total cost of revenue.
Segment information	The chief operating decision maker (“CODM”) is the Chief Executive Officer who reviews financial information presented on a consolidated basis. The Company has one business activity and there are no segment managers who are held accountable by the CODM for operations, operating results and planning for levels or components below the consolidated level. The Company operates in one segment.
Concentrations	Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities, accounts receivable, and restricted cash. The Company maintains all of its cash and cash equivalents in interest-bearing bank accounts and money market accounts. Management believes that the financial institutions that hold the Company’s cash and cash equivalents are financially sound and exposed to minimal credit risk. Deposits held with banks generally exceed the amount of insurance provided on such deposits.
Foreign Currency	Prior to July 1, 2019, the Company’s functional currency was the U.S. dollar for the majority of its foreign operations except for Forescout Technologies, B.V. whose functional currency was the Euro. Translation gains and losses from the application of the U.S. dollar as the reporting currency during the period that the Euro was the functional currency for Forescout Technologies, B.V. were included as a component of accumulated other comprehensive loss on the consolidated balance sheets. The Company re-assessed its functional currency and determined that, as of July 1, 2019, its functional currency for Forescout Technologies, B.V. had changed from the Euro to the U.S. dollar following the transfer of all of the intellectual property from Forescout Technologies, B.V. to the Company effective July 1, 2019. The change in functional currency was accounted for prospectively from July 1, 2019 and financial statements prior to and including the period ended June 30, 2019 were not restated for the change in functional currency. Transactions denominated in currencies other than the applicable functional currency are converted to the functional currency at the exchange rate on the transaction date. At period end, monetary assets and liabilities are remeasured using the current exchange rate at the balance sheet date. Non-monetary assets and liabilities and capital accounts are remeasured using historical exchange rates. Revenue and expenses have been remeasured using the average exchange rates in effect during each period. Resulting foreign currency remeasurement gains and losses are recorded in other income (expense), net on the consolidated statements of operations. Where a non-U.S. currency is the functional currency, translation from that functional currency to the U.S. dollar is performed for balance sheet accounts using exchange rates in effect at the balance sheet date and for revenue and expense accounts using an average exchange rate for the period. Resulting translation adjustments are reported as a component of accumulated other comprehensive loss on the consolidated balance sheets.
Cash and Cash Equivalents	The Company considers all highly liquid investments held at financial institutions with original maturities of three months or less at date of purchase to be cash equivalents. Cash and cash equivalents are stated at cost, which approximates fair value.
Marketable Securities	The Company’s marketable securities consist primarily of commercial paper, corporate debt securities, and U.S. government agency securities. The Company’s marketable securities are classified as available-for-sale and are reported at fair value. The Company determines any realized gains or losses on the sale of available-for-sale securities on a specific identification method, and such gains and losses are recorded as a component of other income, net on the consolidated statements of operations. Unrealized gains and losses of the available-for-sale securities are excluded from earnings and reported as a component of accumulated other comprehensive loss. The Company has classified and accounted for its marketable securities as available-for-sale. After consideration of the Company’s risk versus reward objectives, as well as the Company’s liquidity requirements, the Company may sell these securities prior to their stated maturities. As the Company views these securities as available to support current operations, the Company classifies highly liquid securities with maturities beyond 12 months as current assets under the caption marketable securities in the consolidated balance sheets.
Accounts Receivable	Trade accounts receivable are recorded at the invoiced amount, net of allowances for doubtful accounts. The Company assesses its trade accounts receivable for doubtful accounts based on the collectability of accounts. Management regularly reviews the adequacy of the allowance for doubtful accounts by considering the age of each outstanding invoice, each customer’s expected ability to pay, and the collection history with each customer, to determine whether a specific allowance is appropriate. Accounts receivable that are deemed uncollectible are charged against the allowance for doubtful accounts.
Inventory	Inventory primarily consists of finished goods hardware appliances and production materials. Inventory is stated at the lower of cost or net realizable value 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.
Property and Equipment	Property and equipment is stated at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally three to five years . Demonstration units are not resold after use and are depreciated over the estimated useful life of three years or less. Leasehold improvements are depreciated over the shorter of the estimated useful lives of the improvements or the remaining lease term.
Business Combinations	The Company accounts for acquisitions using the acquisition method of accounting for business combinations . When the Company acquires a business, the purchase price is allocated to the net tangible and identifiable intangible assets acquired based on their estimated fair values. Any residual purchase price is recorded as goodwill. The allocation of the purchase price requires management to make significant estimates in determining the fair values of assets acquired and liabilities assumed, especially with respect to intangible assets. These estimates can include, but are not limited to, the cash flows that an asset is expected to generate in the future, the appropriate weighted-average cost of capital, and the cost savings expected to be derived from acquiring an asset. These estimates are inherently uncertain and unpredictable. During the measurement period, which may be up to one year from the acquisition date, adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed may be recorded, with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of operations.
Goodwill	The excess of the purchase price over the estimated fair value of net assets of businesses acquired in a business combination is recognized as goodwill. Goodwill is tested for impairment annually on October 1st or more frequently if certain indicators are present.
Other Long-Lived Assets	Management reviews long-lived assets, such as property and equipment and finite-lived intangible assets subject to amortization, for events and changes in circumstances that may indicate that carrying amounts of long-lived assets may not be recoverable. When such events or circumstances occur, recoverability of these assets is measured by a comparison of the carrying value to the future undiscounted cash flows the assets are expected to generate. If long-lived assets are considered to be impaired, the impairment to be recognized would equal the amount by which the carrying value of the asset exceeds its fair market value.
Deferred Offering Costs	Deferred offering costs consisted of fees and expenses incurred in connection with the sale of the Company’s common stock in its IPO and Offering, including direct incremental legal, consulting, accounting fees, and other offering-related costs. Upon completion of the Company’s IPO or Offering, these deferred offering costs were reclassified to stockholders’ equity and offset against the proceeds of the offerings.
Product Warranty	The Company provides a standard 90 day warranty on its hardware and software products. The Company also offers its customers post-contract support (“PCS”), which includes a warranty of between one to five -years on hardware. The Company will also provide its customers software releases or updates during the PCS term. The Company accrues for estimated standard warranty costs for those customers that do not purchase PCS at the time of product shipment. These potential warranty claims are accrued as a component of product cost of revenue based on historical experience and other data, which is reviewed periodically for adequacy. Warranty costs associated with PCS are expensed as incurred. To date, the Company has not incurred nor accrued any significant costs associated with product warranty.
Contract Manufacturer Liabilities	Manufacturing, repair, and supply chain management operations are outsourced to a third-party contract manufacturer. These costs are a significant portion of product cost of revenue. Although the Company is contractually obligated to purchase manufactured products, the Company generally does not own the manufactured products as product title transfers from the contract manufacturer to the Company and immediately to the customer upon shipment. The contract manufacturer assembles the Company’s products using design specifications, quality assurance programs, and standards that the Company establishes. Components are procured and assembled based on the Company’s demand forecasts. These forecasts represent management’s best estimates of future demand for the products based upon historical trends and analysis from sales and operations functions as adjusted for overall market conditions. The Company accrues for costs for contractual manufacturing commitments in excess of its forecasted demand, including costs incurred for excess components or for the carrying costs incurred by the contract manufacturer. To date, the Company has not accrued any significant contract manufacturer liabilities.
Redeemable Convertible Preferred and Common Stock Warrant Liabilities	Upon completion of the Company's IPO in October 2017, there were no freestanding warrants to purchase shares of convertible preferred stock. As such, no preferred stock warrant liability remained outstanding after the IPO. Before the Company's IPO, freestanding warrants related to shares that are redeemable or contingently redeemable were classified as a liability in the Company’s consolidated balance sheet. The convertible preferred stock warrants were subject to re-measurement at each balance sheet date, and any change in fair value was recognized in the consolidated statements of operations. The Company adjusted the redeemable convertible preferred stock warrant liability to the estimated fair value of the warrants until either the exercise or the completion of the Company’s IPO, at which time the redeemable convertible preferred stock issuable upon exercise of the warrants became warrants to purchase common stock and the related liability was reclassified to additional paid-in capital in stockholders' equity.
Severance Pay Deposits and Accrued Severance Pay Liability	The Company records a severance pay asset and liability on its consolidated balance sheets related to its employees located in Israel. Under Israeli law and labor agreements, the Company is required to make severance and pension payments to retired or dismissed employees and to employees leaving employment in certain other circumstances. Liabilities for severance pay are calculated pursuant to Israeli severance pay law using the most recent monthly salary for the employees, multiplied by the number of years of employment, and are included in accrued expenses and other liabilities in the Company’s consolidated balance sheets for the current and non-current portions, respectively. The Company’s liability at each respective balance sheet date for its Israeli employees is fully accrued in the accompanying consolidated financial statements. The severance liability is funded through monthly deposits to the employee’s pension and management insurance carriers. The fair value of this deposit is recorded in prepaid expenses and other current assets, and other assets in the Company’s consolidated balance sheets for the current and non-current portions, respectively.
Software Development Costs	Software development costs are not capitalized as the software development process is essentially completed concurrent with the establishment of technological feasibility. As such, all software development costs are expensed as incurred and included in research and development expense in the accompanying consolidated statements of operations.
Advertising Costs	Advertising costs include costs incurred on print, broadcast, and online advertising. Advertising costs are expensed as incurred and included in sales and marketing expense in the accompanying consolidated statements of operations.
Stock-Based Compensation	Stock-based compensation for employees is measured based on the grant date fair value of the award and is expensed over the requisite service period, which is generally the vesting period. The fair value of option awards is determined on the date of grant using the Black-Scholes option pricing model. In applying the Black-Scholes option pricing model, the Company’s determination of the fair value of the option award on the grant date prior to its IPO is affected by the Company’s estimated fair value of the underlying common stock, as well as assumptions relating to subjective variables. Subsequent to its IPO, the Company uses the market closing price for its common stock as reported on the NASDAQ Global Select Market. These variables include the expected term of the award, the expected volatility of the common stock price, the risk-free interest rate, and the expected dividend yield of common stock. Prior to the IPO, the fair value of restricted stock units (“RSUs”) was determined on the date of grant using the Company’s estimated fair value of the underlying common stock. Subsequent to its IPO, the Company uses the market closing price for its common stock as reported on the NASDAQ Global Select Market. Beginning January 1, 2017 with the adoption of Accounting Standards Update (“ASU”) No. 2016-09, the Company elected to recognize forfeitures as they occur, and no longer estimates a forfeiture rate when calculating the stock-based compensation for equity awards.
Income Taxes	Deferred income taxes are recognized using the asset and liability method, whereby deferred tax assets and liabilities are recognized for the expected future tax consequences attributable to differences between the Company’s (1) financial statement carrying amounts and their respective tax bases and (2) operating loss and tax credit carryforwards. Valuation allowances are provided when the expected realization of tax assets does not meet a more-likely-than-not criterion. Due to the Company’s lack of earnings history, the U.S. net deferred tax assets have been fully offset by a valuation allowance. The Company recognizes tax benefits from uncertain tax positions if it is more likely than not that the tax position will be sustained upon examination by a taxing authority based on the technical merits of the position. The tax benefits recognized from such positions are measured based on the largest benefit that has a greater than 50% likelihood to be realized upon settlement. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense in the accompanying consolidated statements of operations, when and if incurred.
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02 (Topic 842), Leases (“ASU 2016-02”), followed by ASU No. 2018-10 (Topic 842), Codification Improvements to Topic 842, Leases (“ASU 2018-10”), and ASU No. 2018-11 (Topic 842), Targeted Improvements (“ASU 2018-11”) in July 2018 (collectively, “Topic 842”). The Company adopted Topic 842 effective January 1, 2019 using the transition method. See Note 6 for the details of any impact on the adoption. Recently Issued and Not Yet Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model which requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. The Company will adopt ASU 2016-13 effective January 1, 2020 with the cumulative effect of adoption recorded as an adjustment to retained earnings. The effect on its consolidated financial statements and related disclosures is not expected to be material. In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes that eliminates certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. The standard is effective for annual and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted. The Company is currently evaluating the timing and impact of the adoption of this standard on its consolidated financial statements.
Revenue Recognition	Revenue Recognition The Company derives its revenue from sale of Software Products, Hardware Products, term contracts, and professional services. All revenue recognized in the consolidated statements of operations is considered to be revenue from contracts with customers. The Company offers its solution across two product groups: (i) products for visibility and control capabilities, and (ii) products for orchestration capabilities and across two product types: (i) software products, and (ii) hardware products. The Company determines revenue recognition through the following steps, which are described in more detail below: • Identification of the contract, or contracts, with a customer — A contract with a customer exists when (i) the Company enters into an enforceable contract with a customer that defines each party’s rights regarding the goods or services to be transferred and identifies the payment terms related to these goods or services, (ii) the contract has commercial substance, and (iii) the Company determines that collection of substantially all consideration for goods or services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration. The Company applies judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors, including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information pertaining to the customer. The Company’s payment terms typically range between 30 to 90 days. • Identification of the performance obligation(s) in the contract — Performance obligations promised in a contract are identified based on the goods or services that will be transferred to the customer that are both capable of being distinct, whereby the customer can benefit from the goods or services either on their own or together with other resources that are readily available from third parties or from the Company, and are distinct in the context of the contract, whereby the transfer of the goods or services is separately identifiable from other promises in the contract. To the extent a contract includes multiple promised goods or services, the Company applies judgment to determine whether promised goods or services are capable of being distinct, and are distinct in the context of the contract. If these criteria are not met, the promised goods or services are accounted for as a combined performance obligation. • Determination of the transaction price — The transaction price is determined based on the consideration that the Company will be entitled to in exchange for transferring goods or services to the customer. In determining the transaction price, the Company considers uncertainties such as historical rates of product returns and/or concessions. • Allocation of the transaction price to the performance obligation(s) in the contract — If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative standalone selling price (“SSP”) basis. The Company determines standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. • Recognition of revenue when, or as, a performance obligation is satisfied — The Company satisfies performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at the time the related performance obligation is satisfied by transferring a promised good or service to a customer. Revenue is recorded net of sales taxes. The following describes the nature of the Company’s primary types of revenue and the revenue recognition policies as they pertain to the types of transactions the Company enters into with its customers. License Revenue License revenue consists of sales of Software Products and Hardware Products. Software Products are sold with either a perpetual license or a term license. License revenue includes the value allocated to license within Software Products subscription contracts. License revenue is recognized at the time of transfer of control, which is generally upon delivery of access to software downloads or shipment, provided that all other revenue recognition criteria have been met. Subscription Revenue Subscription revenue is derived from support and maintenance contracts, the value allocated to support and maintenance within Software Products subscription contracts, and software as a service (“SaaS”) offering contracts. Customers do not have the right to take possession of the cloud-based software. Subscription contracts have terms that are generally either one or three years, but can be up to five years. Subscription revenue is recognized ratably over the term of the contract and any unearned subscription revenue is included in deferred revenue. Professional Services Revenue Professional services revenue is derived primarily from customer fees for optional installation of the Company’s products or training. Generally, the Company recognizes revenue for professional services as the services are rendered. Contract Costs The Company capitalizes contract origination costs that are incremental and recoverable costs of obtaining a contract with a customer. The Company expects that sales commissions and associated payroll taxes and third-party referral fees related to customer contracts are both incremental and recoverable. The contract origination costs are capitalized and amortized to sales and marketing expense when the related performance obligations are met. Incremental contract origination costs relating to products are expensed as the related products are delivered. Incremental contract origination costs relating to term contracts are capitalized and amortized over either the contractual performance period or on a straight-line basis over the average customer life of five years , depending on whether the costs relate to a specific term contract or the customer relationship. The Company determines its average customer life by taking into consideration its customer contracts, technology, and other factors. Capitalized costs are periodically reviewed for impairment. Revenue from Contracts with Customers Contract Assets and Contract Liabilities A contract asset is a right to consideration in exchange for products or services that the Company has transferred to a customer when that right is conditional and is not just subject to the passage of time. The Company has no material contract assets. A receivable will be recorded on the consolidated balance sheets when the Company has unconditional rights to consideration. A contract liability is an obligation to transfer products or services for which the Company has received consideration, or for which an amount of consideration is due from the customer. Contract liabilities include customer deposits under non-cancelable contracts and current and non-current deferred revenue balances. The Company’s contract balances are reported in a net contract asset or liability position on a contract-by-contract basis at the end of each reporting period. Performance Obligations The majority of the contracted but not invoiced performance obligations are subject to cancellation terms. Revenue allocated to remaining performance obligations represent contracted revenue that has not yet been recognized (“contracted not recognized”), which includes deferred revenue, certain customer deposits, and non-cancelable amounts that will be invoiced and recognized as revenue in future periods and excludes performance obligations that are subject to cancellation terms. Contracted not recognized revenue was $188.9 million as of December 31, 2019 , of which the Company expects to recognize approximately 60% of the revenue over the next 12 months and the remainder thereafter. Practical Expedients The Company does not disclose the value of consideration associated with unsatisfied or partially unsatisfied performance obligations for contracts for which the Company recognizes revenue at the amount to which it will have the right to invoice for services performed. The Company also reflects the aggregate effect of all modifications to a contract that occurred before the earliest period presented in the current period’s financial statements instead of retrospectively restating contracts for all previous contract modifications.
Leases	Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company elected to combine the lease components (e.g., fixed payments including rent, real estate taxes, and insurance costs) and the non-lease components (e.g., common-area maintenance costs) for all classes of underlying assets, and to not reassess prior conclusions related to contracts containing leases, lease classification, and initial direct costs. The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use assets, current operating lease liabilities, and non-current operating lease liabilities on the Company’s consolidated balance sheets. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate, the Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. For leases that commenced prior to January 1, 2019, the Company uses the incremental borrowing rate as of January 1, 2019 to determine the present value of future payments on those leases. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. The lease terms may include options to extend the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term.

Revenue, Deferred Revenue and_2

Revenue, Deferred Revenue and Deferred Commissions (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract with Customer, Liability	Significant changes in contract liabilities during the periods presented are as follows (in thousands): Contract Liabilities Balance as of December 31, 2017 135,867 Additions 327,650 Assumed in a business combination 6,297 Gross revenue recognized (297,783 ) Balance as of December 31, 2018 172,031 Additions 353,601 Gross revenue recognized (336,725 ) Balance as of December 31, 2019 $ 188,907
Disaggregation of Revenue	The following table depicts the disaggregation of revenue according to revenue type and is consistent with how the Company evaluates its financial performance (in thousands): Year Ended December 31, 2019 2018 2017 Revenue: License Software products Perpetual license $ 104,521 $ 106,978 $ 49,405 Term license 23,459 — — Hardware products 47,135 55,689 75,943 Subscription SaaS 22 — — Support and maintenance 142,755 118,572 86,691 Professional services 18,909 16,412 12,365 Total revenue $ 336,801 $ 297,651 $ 224,404

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
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): December 31, 2019 December 31, 2018 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents: Cash $ 62,188 $ — $ — $ 46,017 $ — $ — Money market accounts 6,842 — — 20,878 — — Total cash and cash equivalents 69,030 — — 66,895 — — Marketable securities: Commercial paper — 1,998 — — 3,991 — Corporate debt securities — 24,168 — — 35,640 — U.S. government securities — 3,015 — — 8,001 — Total marketable securities — 29,181 — — 47,632 — Restricted cash (current and non-current) 2,561 — — 2,117 — — Total financial assets $ 71,591 $ 29,181 $ — $ 69,012 $ 47,632 $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Unrealized Losses and Fair Value of Available-for-Sale Securities	The following table summarizes the unrealized gains and losses, and fair value of the Company’s marketable securities as of December 31, 2019 and 2018 (in thousands): December 31, 2019 December 31, 2018 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Amortized Cost Unrealized Gains Unrealized Losses Fair Value Marketable securities: Available-for-sale: Commercial paper $ 1,998 $ — $ — $ 1,998 $ 3,991 $ — $ — $ 3,991 Corporate debt securities 24,122 46 — 24,168 35,730 — (90 ) 35,640 U.S. government securities 3,012 3 — 3,015 8,012 — (11 ) 8,001 Total marketable securities $ 29,132 $ 49 $ — $ 29,181 $ 47,733 $ — $ (101 ) $ 47,632
Investments Classified by Contractual Maturity Date	The following table summarizes the amortized cost and fair value of the Company’s available-for-sale securities as of December 31, 2019 and 2018 , by the contractual maturity date (in thousands): 2019 2018 Amortized Cost Fair Value Amortized Cost Fair Value Due within one year $ 29,132 $ 29,181 $ 47,733 $ 47,632 Total $ 29,132 $ 29,181 $ 47,733 $ 47,632
Schedule of Unrealized Loss on Marketable Securities	For individual marketable securities that were in an unrealized loss position as of December 31, 2018 , the fair value and gross unrealized loss for these securities aggregated by investment category and length of time in an unrealized loss position are presented in the following tables (in thousands): December 31, 2018 Less Than 12 Months Greater Than 12 Months Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Corporate debt securities $ 4,020 $ (3 ) $ 31,620 $ (87 ) $ 35,640 $ (90 ) U.S. government securities — — 8,001 (11 ) 8,001 (11 ) Total $ 4,020 $ (3 ) $ 39,621 $ (98 ) $ 43,641 $ (101 )

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): December 31, 2019 2018 Leasehold improvements $ 19,883 $ 19,832 Computer, equipment and software 16,712 14,591 Furniture and fixtures 4,586 4,361 Demonstration units 3,805 3,262 Total property and equipment 44,986 42,046 Less: accumulated depreciation (21,151 ) (17,697 ) Total property and equipment, net $ 23,835 $ 24,349

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Maturity of Lease Liabilities	Maturities of lease liabilities as of December 31, 2019 were as follows (in thousands): Years Ending December 31, Operating Leases 2020 $ 8,280 2021 7,773 2022 7,455 2023 7,384 2024 7,315 Thereafter 8,326 Total lease payments $ 46,533 Less: Imputed interest 8,568 Present value of lease liabilities $ 37,965
Lease Term and Discount Rate	Lease Term and Discount Rate December 31, 2019 Operating leases Weighted-average remaining lease term 6 years Weighted-average discount rate 7.1 %
Lease Cost	Other information (in thousands) December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 6,565 Leased assets obtained in exchange for new operating lease liabilities $ 15,159
Future Minimum Lease Payments by Fiscal Year Under Non-Cancelable Leases Prior to the Adoption of Topic 840	As of December 31, 2018 , prior to the adoption of Topic 842, future minimum lease payments by fiscal year under non-cancelable leases are as follows (in thousands): Years Ending December 31, Operating 2019 $ 5,551 2020 4,188 2021 4,307 2022 4,435 2023 4,461 2024 and thereafter 11,933 Total $ 34,875

Acquisitions, Goodwill, and I_2

Acquisitions, Goodwill, and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Allocation of Purchase Price	The Bullguard Acquisition has been accounted for as a business combination and is intended to support and accelerate the Company’s development of cloud-delivered products as part of its end-to-end device visibility and control platform. The purchase price was allocated as follows (in thousands): Amount Intangible assets - Developed technology $ 3,790 Goodwill 6,481 Total purchase price allocation $ 10,271 The Purchase Consideration of $109.3 million was allocated as follows (in thousands): Amount Net tangible assets acquired $ 686 Intangible assets 19,500 Deferred tax liabilities, net (3,486 ) Goodwill 92,648 Total purchase price allocation $ 109,348
Schedule of Identifiable Intangible Assets	The following table sets forth the components of identifiable intangible assets acquired and their estimated useful lives as of the date of acquisition (in thousands, except useful life): Intangible Assets Cost Weighted Average Useful Life (in years) Developed technology $ 13,300 7.0 Customer relationships 6,200 5.0 Total intangible assets acquired $ 19,500 6.4
Schedule of Goodwill	The changes in the carrying amount of goodwill are as follows (in thousands): Amount Balance as of December 31, 2017 $ — Goodwill acquired 92,648 Foreign currency translation adjustments (166 ) Balance as of December 31, 2018 92,482 Goodwill acquired 6,481 Goodwill adjustments (565 ) Foreign currency translation adjustments (380 ) Balance as of December 31, 2019 $ 98,018
Schedule of Finite-Lived Intangible Assets	Intangible assets subject to amortization realized from acquisitions are as follows (in thousands): December 31, 2019 December 31, 2018 Cost Accumulated Amortization Foreign Currency Translation Adjustments Net Cost Accumulated Amortization Foreign Currency Translation Adjustments Net Developed technology $ 17,090 $ (2,392 ) $ (85 ) $ 14,613 $ 13,300 $ (280 ) $ (24 ) $ 12,996 Customer relationships 6,200 (1,405 ) (41 ) 4,754 6,200 (183 ) (11 ) 6,006 $ 23,290 $ (3,797 ) $ (126 ) $ 19,367 $ 19,500 $ (463 ) $ (35 ) $ 19,002
Schedule of Expected Future Amortization Expense of Intangible Assets	The expected future annual amortization expense of intangible assets as of December 31, 2019 is presented below (in thousands): Year Ending December 31, Amount 2020 $ 4,057 2021 4,057 2022 4,057 2023 3,667 2024 and thereafter 3,529 Total $ 19,367

Debt Agreements (Tables)

Debt Agreements (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Carrying Value of Notes Payable	The following table presents the carrying value of the Company’s notes payable (in thousands): December 31, 2019 2018 Principal amount of notes payable $ 8,325 $ 15,825 Unamortized debt discount (77 ) (246 ) Net carrying amount of notes payable 8,248 15,579 Less current portion (8,248 ) (7,331 ) Non-current portion of notes payable $ — $ 8,248

Common Stock and Stockholders_2

Common Stock and Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Common Stock Reserved	As of December 31, 2019 , common stock reserved, on an as-if converted basis for issuance are as follows (in thousands): December 31, 2019 Reserved for future issuance under equity award plans 4,107 Common stock options outstanding 3,066 Restricted stock units outstanding 6,391 Total common stock reserved for issuance 13,564
Schedule of Option Activity under the Plan	The following table summarizes option activity under the Plan and related information (in thousands, except per share and contractual life amounts): Options Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2017 9,314 $ 10.63 7.2 $ 198,012 Granted 44 $ 30.81 Exercised (2,979 ) $ 8.13 Forfeited (366 ) $ 16.59 Balance—December 31, 2018 6,013 $ 11.65 6.4 $ 86,624 Exercised (2,744 ) $ 10.41 Forfeited (203 ) $ 18.01 Balance—December 31, 2019 3,066 $ 12.33 5.6 $ 62,759 Options vested and exercisable—December 31, 2019 2,790 $ 11.55 5.4 $ 59,282
Schedule of RSU Activity under the Plan	The following table summarizes RSU and PSU activity under the Plan and related information (in thousands, except per share and contractual life amounts): RSUs and PSUs Outstanding Number Weighted- Weighted- Aggregate Balance—December 31, 2017 4,216 $ 20.57 1.7 $ 134,448 Granted 3,354 $ 30.94 Released (1,607 ) $ 14.78 Forfeited (254 ) $ 26.80 Balance—December 31, 2018 5,709 $ 28.01 1.8 $ 148,389 Granted 3,145 $ 34.86 Released (1,609 ) $ 26.77 Forfeited (854 ) $ 30.45 Balance—December 31, 2019 6,391 $ 31.37 1.7 $ 209,621
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 consolidated statements of operations is as follows (in thousands): Year Ended December 31, 2019 2018 2017 Cost of revenue: License $ 346 $ 253 $ 103 Subscription 1,851 1,517 1,089 Professional services 1,730 1,498 1,202 Research and development 12,303 10,161 6,213 Sales and marketing 25,698 24,999 14,451 General and administrative 13,522 15,069 19,538 Total $ 55,450 $ 53,497 $ 42,596
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 and ESPP purchase rights for the periods presented are as follows: Year Ended December 31, 2019 2018 2017 Employee Stock Options Fair value of common stock $— $29.92 – $30.97 $16.73 – $31.16 Risk-free interest rate —% 2.4% – 2.8% 1.9% – 2.2% Expected term (in years) 0 6.1 6.0 – 6.1 Volatility —% 48% 46% – 49% Dividend yield —% —% —% Employee Stock Purchase Plan Fair value of common stock $33.69 – $35.03 $24.65 – $31.00 $25.12 Risk-free interest rate 1.6% – 2.4% 2.14% – 2.52% 1.4% Expected term (in years) 0.5 0.5 0.5 Volatility 35% – 40% 30% – 43% 30% Dividend yield —% —% —%

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of loss before provision for income taxes, domestic and foreign	The components of loss before provision for income taxes are as follows (in thousands): Year Ended December 31, 2019 2018 2017 Domestic $ (108,234 ) $ (85,252 ) $ (82,292 ) Foreign 8,420 13,361 3,411 Total $ (99,814 ) $ (71,891 ) $ (78,881 )
Schedule of components of income tax expense	The provision for income taxes consists of the following (in thousands): Year Ended December 31, 2019 2018 2017 Current Federal $ 14 $ 1 $ 17 State 93 56 50 Foreign 23,857 3,263 1,788 Total current 23,964 3,320 1,855 Deferred Foreign (5,243 ) (375 ) (16 ) Total deferred $ (5,243 ) $ (375 ) $ (16 ) Total $ 18,721 $ 2,945 $ 1,839
Schedule of deferred tax assets and liabilities	Significant components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2019 2018 Deferred tax assets: Federal and state net operating losses $ 91,529 $ 59,803 Research/other credits 3,898 2,913 Non-deductible and accrued expenses 2,780 4,756 Deferred revenue 16,576 14,040 Property and equipment 430 506 Stock-based compensation 10,363 10,323 Lease liability 6,560 — Other 705 1,024 Gross deferred tax assets 132,841 93,365 Valuation allowance (112,882 ) (83,376 ) Net deferred tax assets 19,959 9,989 Deferred tax liabilities: Acquired intangible assets (3,807 ) (4,117 ) Right of use asset (4,738 ) — Deferred commission (8,684 ) (8,691 ) Others (27 ) (116 ) Net deferred tax liabilities (17,256 ) (12,924 ) Total $ 2,703 $ (2,935 )
Schedule of effective income tax rate reconciliation	Reconciliation of the statutory federal income tax to the Company’s effective tax (in thousands): Year Ended December 31, 2019 2018 2017 Tax at federal statutory rate $ (20,972 ) $ (15,097 ) $ (30,385 ) State, net of federal benefit 92 61 60 Meals and entertainment disallowance 835 799 365 Stock-based compensation (7,852 ) (6,215 ) 4,097 Non-deductible warrant expenses — — 272 Tax Reform federal rate change — — 36,460 Impact of intangible property transfer 20,551 — — Change in valuation allowance 25,874 23,929 (10,512 ) Other 193 (532 ) 1,482 Total $ 18,721 $ 2,945 $ 1,839
Schedule of Unrecognized Tax Benefits Roll Forward	A reconciliation of the gross unrecognized tax benefit is as follows (in thousands): Year Ended December 31, 2019 2018 2017 Unrecognized tax benefits at the beginning of the period $ 1,267 $ 1,727 $ 1,050 Additions for tax positions taken in prior years 64 104 248 Additions for tax positions taken in current year 20,816 195 845 Reductions for tax positions taken in prior years — (759 ) — Settlements with taxing authorities — — (416 ) Statute of limitation expirations (104 ) — — Unrecognized tax benefits at the end of the period $ 22,043 $ 1,267 $ 1,727

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
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 per share amounts): Year Ended December 31, 2019 2018 2017 Net loss $ (118,535 ) $ (74,836 ) $ (80,720 ) Deemed dividend on the conversion of Series G redeemable convertible preferred stock — — 12,810 Net loss attributable to common stockholders $ (118,535 ) $ (74,836 ) $ (93,530 ) Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted 45,957 40,980 11,405 Net loss per share attributable to common stockholders, basic and diluted $ (2.58 ) $ (1.83 ) $ (8.20 )
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 (in thousands). Year Ended December 31, 2019 2018 2017 Options to purchase common stock 3,066 6,013 9,314 Unvested early exercised common shares — 47 146 Unvested restricted stock units 6,391 5,709 4,216 Shares estimated under ESPP 196 233 221 Warrants to purchase common stock — — 83

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
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): Year Ended December 31, 2019 2018 2017 Revenue: Americas United States $ 236,878 $ 215,322 $ 165,140 Other Americas 11,267 6,883 6,122 Total Americas 248,145 222,205 171,262 Europe, Middle East, and Africa (“EMEA”) 54,228 52,214 36,664 Asia Pacific and Japan (“APJ”) 34,428 23,232 16,478 Total revenue $ 336,801 $ 297,651 $ 224,404
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): December 31, 2019 2018 Long-lived assets, net: United States $ 18,598 $ 18,570 Israel 4,370 5,057 Other 867 722 Total long-lived assets, net $ 23,835 $ 24,349

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	The following tables set forth selected unaudited quarterly consolidated statements of operations data for each of the eight quarters in the period ended December 31, 2019 . The information for each of these quarters has been prepared on the same basis as the audited annual consolidated financial statements included elsewhere in this report and, in the opinion of management, includes all adjustments, which consist only of normal recurring adjustments, necessary for the fair presentation of the results of operations for these periods in accordance with GAAP. This data should be read in conjunction with our audited consolidated financial statements and related notes included elsewhere in this report. These quarterly operating results are not necessarily indicative of our operating results for a full year or any future period. Three Months Ended December 31, September 30, June 30, March 31, December 31, September 30, June 30, March 31, (In thousands, except per share amounts) Revenue: License $ 48,401 $ 50,203 $ 38,831 $ 37,680 $ 47,482 $ 51,082 $ 34,323 $ 29,780 Subscription 37,586 36,570 34,822 33,799 32,888 30,339 28,986 26,359 Professional services 5,344 4,849 4,627 4,089 4,362 4,207 4,285 3,558 Total revenue 91,331 91,622 78,280 75,568 84,732 85,628 67,594 59,697 Cost of revenue: License (1) 8,180 9,892 5,622 7,607 6,852 8,947 4,919 7,136 Subscription (1) 5,795 5,376 5,599 5,207 4,613 4,069 3,732 3,801 Professional services (1) 7,050 6,429 6,235 6,186 6,021 6,181 6,062 5,549 Total cost of revenue 21,025 21,697 17,456 19,000 17,486 19,197 14,713 16,486 Total gross profit 70,306 69,925 60,824 56,568 67,246 66,431 52,881 43,211 Operating expenses: Research and development (1) 24,302 20,556 19,440 18,497 17,161 15,062 14,803 14,687 Sales and marketing (1) 49,915 51,035 56,173 55,923 50,464 46,098 45,039 42,279 General and administrative (1) 15,649 15,318 15,838 16,213 16,849 13,880 13,260 13,732 Total operating expenses 89,866 86,909 91,451 90,633 84,474 75,040 73,102 70,698 Loss from operations (19,560 ) (16,984 ) (30,627 ) (34,065 ) (17,228 ) (8,609 ) (20,221 ) (27,487 ) Interest expense (105 ) (156 ) (142 ) (93 ) (237 ) (208 ) (225 ) (243 ) Other income, net 422 374 505 617 527 865 513 662 Loss before income taxes (19,243 ) (16,766 ) (30,264 ) (33,541 ) (16,938 ) (7,952 ) (19,933 ) (27,068 ) Income tax provision 767 16,747 496 711 1,010 334 473 1,128 Net loss $ (20,010 ) $ (33,513 ) $ (30,760 ) $ (34,252 ) $ (17,948 ) $ (8,286 ) $ (20,406 ) $ (28,196 ) Net loss per share, basic and diluted $ (0.42 ) $ (0.72 ) $ (0.68 ) $ (0.78 ) $ (0.42 ) $ (0.20 ) $ (0.50 ) $ (0.74 ) Weighted-average shares used to compute net loss per share, basic and diluted 47,511 46,584 45,494 44,196 43,016 42,064 40,457 38,313 _____________________ (1) Includes stock-based compensation expense as follows: Three Months Ended December 31, September 30, June 30, March 31, December 31, September 30, June 30, March 31, (In thousands) Cost of revenue: License $ 99 $ 75 $ 89 $ 83 $ 79 $ 67 $ 54 $ 53 Subscription 484 454 470 443 418 349 371 379 Professional services 493 415 421 401 386 366 352 394 Research and development 3,494 3,040 2,691 3,078 2,688 2,613 2,513 2,347 Sales and marketing 5,684 6,330 7,198 6,486 6,804 6,165 5,850 6,180 General and administrative 3,481 3,508 3,196 3,337 3,578 3,458 3,796 4,237 Total $ 13,735 $ 13,822 $ 14,065 $ 13,828 $ 13,953 $ 13,018 $ 12,936 $ 13,590

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies - Company Background (Details)	12 Months Ended
	Dec. 31, 2019product
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of product groups	2
Number of product types	2

Revenue, Deferred Revenue and_3

Revenue, Deferred Revenue and Deferred Commissions - Narrative (Details)	12 Months Ended
	Dec. 31, 2019USD ($)product	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Number of product groups | product	2
Number of product types | product	2
Capitalized contract cost, amortization period	5 years
Capitalized contract cost	$ 36,000,000	$ 35,900,000
Capitalized contract cost, amortization	14,400,000	14,900,000	$ 11,400,000
Capitalized contract cost, impairment loss	0	0	$ 0
Contract with customer, asset	0
Deferred revenue, revenue recognized that was previously deferred	$ 101,900,000	$ 80,000,000
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payment term period	30 days
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payment term period	90 days

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Initial Public Offering and Follow-On Offering (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 31, 2017	Mar. 31, 2018	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Subsidiary, Sale of Stock [Line Items]
IPO price per share (in dollars per share)		$ 29
Offering costs				$ 0	$ 1,542	$ 4,245
Exercised (shares)		425,436		2,744,000	2,979,000
Common stock
Subsidiary, Sale of Stock [Line Items]
Shares converted into common stock (in shares)			25,370,616			24,845,000
Exercised (shares)				4,613,000	4,616,000	306,000
IPO
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in IPO (in shares)	6,072,000
IPO price per share (in dollars per share)	$ 22		$ 22
Consideration received from IPO	$ 124,200
Offering costs	$ 4,500
Follow-On Offering
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in IPO (in shares)		500,000
Consideration received from IPO		$ 16,400
Offering costs		1,200
Underwriters discounts and commissions		700
Proceeds from exercise of stock options		$ 2,600
Follow-On Offering – Shares From Existing Shareholders
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in IPO (in shares)		4,572,650

Revenue, Deferred Revenue and_4

Revenue, Deferred Revenue and Deferred Commissions - Significant Changes in Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 172,031	$ 135,867
Additions	353,601	327,650
Assumed in a business combination		6,297
Gross revenue recognized	(336,725)	(297,783)
Ending balance	$ 188,907	$ 172,031

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Reverse Stock Split (Details)	Oct. 16, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reverse stock split conversion ratio	0.5

Revenue, Deferred Revenue and_5

Revenue, Deferred Revenue and Deferred Commissions - Performance Obligations (Details) $ in Millions	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation	$ 188.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, percentage	60.00%
Performance obligation expected to be satisfied, expected timing	12 months

Description of Business and S_6

Description of Business and Summary of Significant Accounting Policies - Segment Information (Details)	12 Months Ended
	Dec. 31, 2019business_activitysegment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of business activities | business_activity	1
Number of segments | segment	1

Revenue, Deferred Revenue and_6

Revenue, Deferred Revenue and Deferred Commissions - Disaggregation of Revenue According to Revenue Type (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 91,331	$ 91,622	$ 78,280	$ 75,568	$ 84,732	$ 85,628	$ 67,594	$ 59,697	$ 336,801	$ 297,651	$ 224,404
Perpetual license
Disaggregation of Revenue [Line Items]
Revenue									104,521	106,978	49,405
Term license
Disaggregation of Revenue [Line Items]
Revenue									23,459	0	0
Hardware products
Disaggregation of Revenue [Line Items]
Revenue									47,135	55,689	75,943
SaaS
Disaggregation of Revenue [Line Items]
Revenue									22	0	0
Support and maintenance
Disaggregation of Revenue [Line Items]
Revenue									142,755	118,572	86,691
Professional services
Disaggregation of Revenue [Line Items]
Revenue									$ 18,909	$ 16,412	$ 12,365

Description of Business and S_7

Description of Business and Summary of Significant Accounting Policies - Concentrations (Details) - manufacturer	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Number of contract manufacturers	1
Customer Concentration Risk | Accounts Receivable | Customer One
Concentration Risk [Line Items]
Concentration risk percentage	17.00%	17.00%
Customer Concentration Risk | Accounts Receivable | Customer Two
Concentration Risk [Line Items]
Concentration risk percentage	17.00%	15.00%
Customer Concentration Risk | Accounts Receivable | Customer Three
Concentration Risk [Line Items]
Concentration risk percentage		11.00%
Customer Concentration Risk | Accounts Receivable | Customer Four
Concentration Risk [Line Items]
Concentration risk percentage		11.00%
Customer Concentration Risk | Revenue | Customer One
Concentration Risk [Line Items]
Concentration risk percentage	22.00%	22.00%	31.00%
Customer Concentration Risk | Revenue | Customer Two
Concentration Risk [Line Items]
Concentration risk percentage	18.00%	18.00%	22.00%
Customer Concentration Risk | Revenue | Customer Three
Concentration Risk [Line Items]
Concentration risk percentage	12.00%	13.00%	16.00%

Description of Business and S_8

Description of Business and Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restricted cash - current	$ 1,006	$ 851	$ 202
Restricted cash - non current	$ 1,555	$ 1,266	$ 4,146

Description of Business and S_9

Description of Business and Summary of Significant Accounting Policies - Property and Equipment and Product Warranty (Details)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Standard product warranty period	90 days
Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Extended product warranty period	1 year
Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Extended product warranty period	5 years
Demonstration units
Property, Plant and Equipment [Line Items]
Useful life	3 years

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financial Assets
Marketable securities	$ 29,181	$ 47,632
Commercial paper
Financial Assets
Marketable securities	1,998	3,991
Corporate debt securities
Financial Assets
Marketable securities	24,168	35,640
U.S. government securities
Financial Assets
Marketable securities	3,015	8,001
Recurring | Level 1
Financial Assets
Cash and cash equivalents	69,030	66,895
Restricted cash (current and non-current)	2,561	2,117
Total financial assets	71,591	69,012
Recurring | Level 1 | Debt Securities
Financial Assets
Marketable securities	0	0
Recurring | Level 1 | Commercial paper
Financial Assets
Marketable securities	0	0
Recurring | Level 1 | Corporate debt securities
Financial Assets
Marketable securities	0	0
Recurring | Level 1 | U.S. government securities
Financial Assets
Marketable securities	0	0
Recurring | Level 1 | Cash
Financial Assets
Cash and cash equivalents	62,188	46,017
Recurring | Level 1 | Money market accounts
Financial Assets
Cash and cash equivalents	6,842	20,878
Recurring | Level 2
Financial Assets
Cash and cash equivalents	0	0
Restricted cash (current and non-current)	0	0
Total financial assets	29,181	47,632
Recurring | Level 2 | Debt Securities
Financial Assets
Marketable securities	29,181	47,632
Recurring | Level 2 | Commercial paper
Financial Assets
Marketable securities	1,998	3,991
Recurring | Level 2 | Corporate debt securities
Financial Assets
Marketable securities	24,168	35,640
Recurring | Level 2 | U.S. government securities
Financial Assets
Marketable securities	3,015	8,001
Recurring | Level 2 | Cash
Financial Assets
Cash and cash equivalents	0	0
Recurring | Level 2 | Money market accounts
Financial Assets
Cash and cash equivalents	0	0
Recurring | Level 3
Financial Assets
Cash and cash equivalents	0	0
Restricted cash (current and non-current)	0	0
Total financial assets	0	0
Recurring | Level 3 | Debt Securities
Financial Assets
Marketable securities	0	0
Recurring | Level 3 | Commercial paper
Financial Assets
Marketable securities	0	0
Recurring | Level 3 | Corporate debt securities
Financial Assets
Marketable securities	0	0
Recurring | Level 3 | U.S. government securities
Financial Assets
Marketable securities	0	0
Recurring | Level 3 | Cash
Financial Assets
Cash and cash equivalents	0	0
Recurring | Level 3 | Money market accounts
Financial Assets
Cash and cash equivalents	$ 0	$ 0

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 29,132	$ 47,733
Unrealized Gains	49	0
Unrealized Losses	0	(101)
Fair Value	29,181	47,632
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,998	3,991
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	1,998	3,991
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	24,122	35,730
Unrealized Gains	46	0
Unrealized Losses	0	(90)
Fair Value	24,168	35,640
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,012	8,012
Unrealized Gains	3	0
Unrealized Losses	0	(11)
Fair Value	$ 3,015	$ 8,001

Marketable Securities - Maturit

Marketable Securities - Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Amortized Cost
Due within one year	$ 29,132	$ 47,733
Amortized Cost	29,132	47,733
Fair Value
Due within one year	29,181	47,632
Total	$ 29,181	$ 47,632

Marketable Securities - Narrati

Marketable Securities - Narrative (Details)	12 Months Ended
	Dec. 31, 2018USD ($)security	Dec. 31, 2019security
Investments, Debt and Equity Securities [Abstract]
Marketable securities in unrealized loss positions | security	13	0
Other than temporary impairment | $	$ 0

Marketable Securities - Continu

Marketable Securities - Continuous Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months	$ 4,020
Greater Than 12 Months	39,621
Total	43,641
Unrealized Loss
Less Than 12 Months	(3)
Greater Than 12 Months	(98)
Total	(101)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months	4,020
Greater Than 12 Months	31,620
Total	35,640
Unrealized Loss
Less Than 12 Months	(3)
Greater Than 12 Months	(87)
Total	(90)
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months	0
Greater Than 12 Months	8,001
Total	8,001
Unrealized Loss
Less Than 12 Months	0
Greater Than 12 Months	(11)
Total	$ (11)

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 44,986	$ 42,046
Less: accumulated depreciation	(21,151)	(17,697)
Total property and equipment, net	23,835	24,349
Depreciation expense	8,600	7,500	$ 6,100
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	19,883	19,832
Computer, equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	16,712	14,591
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	4,586	4,361
Demonstration units
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,805	$ 3,262

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 29,626
Operating lease liabilities	$ 37,965
Lease term	7 years
Lease renewal term	5 years
Operating lease cost	$ 9,400
Rent expense		$ 6,400	$ 5,600
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets				$ 20,300
Operating lease liabilities				$ 20,300

Leases - Maturity of Lease Liab

Leases - Maturity of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 8,280
2021	7,773
2022	7,455
2023	7,384
2024	7,315
Thereafter	8,326
Total lease payments	46,533
Less: Imputed interest	8,568
Present value of lease liabilities	$ 37,965

Leases - Additional Disclosures

Leases - Additional Disclosures (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Weighted-average remaining lease term	6 years
Weighted-average discount rate	7.10%
Operating cash flows from operating leases	$ 6,565
Leased assets obtained in exchange for new operating lease liabilities	$ 15,159

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments by Fiscal Year Under Non-Cancelable Leases Prior to the Adoption of Topic 840 (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 5,551
2020	4,188
2021	4,307
2022	4,435
2023	4,461
2024 and thereafter	11,933
Total	$ 34,875

Acquisitions, Goodwill, and I_3

Acquisitions, Goodwill, and Intangible Assets - Narrative (Details) - USD ($)	Oct. 02, 2019	Nov. 07, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Acquisition related costs				$ 2,700,000
Amortization of intangible assets			$ 3,300,000	$ 500,000	$ 0
Bullguard Israel Ltd.
Business Acquisition [Line Items]
Cash purchase price	$ 10,300,000
SecurityMatters, B.V.
Business Acquisition [Line Items]
Weighted-average useful life		6 years 4 months 24 days
Percentage of voting interests acquired		100.00%
Business combination, consideration transferred		$ 109,300,000
Escrow deposit		6,200,000
Unvested restricted stock units | SecurityMatters, B.V.
Business Acquisition [Line Items]
RSUs issued in connection with acquisition		$ 5,900,000
Award vesting period		4 years
Future cash payments for unvested equity awards | SecurityMatters, B.V.
Business Acquisition [Line Items]
Unvested equity award cash amounts		$ 1,200,000
Developed Technology | Bullguard Israel Ltd.
Business Acquisition [Line Items]
Weighted-average useful life			4 years
Developed Technology | SecurityMatters, B.V.
Business Acquisition [Line Items]
Weighted-average useful life		7 years

Acquisitions, Goodwill, and I_4

Acquisitions, Goodwill, and Intangible Assets - Allocation of Purchase Price (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Oct. 02, 2019	Dec. 31, 2018	Nov. 07, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 98,018		$ 92,482		$ 0
Bullguard Israel Ltd.
Business Acquisition [Line Items]
Intangible assets		$ 3,790
Goodwill		6,481
Total purchase price allocation		$ 10,271
SecurityMatters, B.V.
Business Acquisition [Line Items]
Net tangible assets acquired				$ 686
Intangible assets				19,500
Deferred tax liabilities, net				3,486
Goodwill				92,648
Total purchase price allocation				$ 109,348

Acquisitions, Goodwill, and I_5

Acquisitions, Goodwill, and Intangible Assets - Schedule of Identifiable Intangible Assets Acquired (Details) - USD ($) $ in Thousands	Nov. 07, 2018	Dec. 31, 2019
SecurityMatters, B.V.
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 19,500
Weighted Average Useful Life (in years)	6 years 4 months 24 days
SecurityMatters, B.V. | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 13,300
Weighted Average Useful Life (in years)	7 years
SecurityMatters, B.V. | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 6,200
Weighted Average Useful Life (in years)	5 years
Bullguard Israel Ltd. | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life (in years)		4 years

Acquisitions, Goodwill, and I_6

Acquisitions, Goodwill, and Intangible Assets - Schedule of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 92,482	$ 0
Goodwill acquired	6,481	92,648
Goodwill adjustments	(565)
Foreign currency translation adjustments	(380)	(166)
Goodwill, ending balance	$ 98,018	$ 92,482

Acquisitions, Goodwill, and I_7

Acquisitions, Goodwill, and Intangible Assets - Intangible Assets Subject to Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Cost	$ 23,290	$ 19,500
Accumulated Amortization	(3,797)	(463)
Foreign Currency Translation Adjustments	(126)	(35)
Net	19,367	19,002
Developed technology
Finite-Lived Intangible Assets [Line Items]
Cost	17,090	13,300
Accumulated Amortization	(2,392)	(280)
Foreign Currency Translation Adjustments	(85)	(24)
Net	14,613	12,996
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	6,200	6,200
Accumulated Amortization	(1,405)	(183)
Foreign Currency Translation Adjustments	(41)	(11)
Net	$ 4,754	$ 6,006

Acquisitions, Goodwill, and I_8

Acquisitions, Goodwill, and Intangible Assets - Expected Future Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
2020	$ 4,057
2021	4,057
2022	4,057
2023	3,667
2024 and thereafter	3,529
Total	$ 19,367	$ 19,002

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Dec. 31, 2019USD ($)
Operating Leased Assets [Line Items]
Purchase obligations	$ 4.6
Contract manufacturer commitments
Operating Leased Assets [Line Items]
Contract manufacturer commitments	$ 7

Debt Agreements - Narrative (De

Debt Agreements - Narrative (Details)	Apr. 04, 2019	Dec. 22, 2016USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Amortization of debt discount (premium)			$ 200,000	$ 300,000	$ 300,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding revolving line of credit			0	0
Line of Credit | Amended Loan and Security Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Percentage of qualified accounts receivable		80.00%
Face amount		$ 30,000,000
Maximum credit available for borrowing		$ 40,000,000
Quick ratio required		1.25
Monthly installments of principal		$ 625,000
Stated interest rate		3.25%
Additional payment at maturity		$ 825,000
Maturity period extension term	2 years
Notes Payable to Banks
Debt Instrument [Line Items]
Future principal payments			$ 8,325,000	$ 15,825,000

Debt Agreements - Carrying Valu

Debt Agreements - Carrying Value of Notes Payable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Less current portion	$ (8,248)	$ (7,331)
Non-current portion of notes payable	0	8,248
Notes Payable to Banks
Debt Instrument [Line Items]
Principal amount of notes payable	8,325	15,825
Unamortized debt discount	(77)	(246)
Net carrying amount of notes payable	8,248	15,579
Less current portion	(8,248)	(7,331)
Non-current portion of notes payable	$ 0	$ 8,248

Common Stock and Stockholders_3

Common Stock and Stockholders' Equity - Narrative (Details) - USD ($)	Oct. 31, 2017	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 05, 2019	Mar. 31, 2018	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of redeemable convertible preferred stock issued (in shares)					0
Shares of redeemable convertible preferred stock outstanding (in shares)			0	0	0	0			18,469,000
Shares issued as stock dividend (in shares)		582,254
IPO price per share (in dollars per share)								$ 29
Common stock reserved for issuance (shares)				13,564,000
Number of shares available for grant (in shares)				4,100,000	3,900,000
Early exercises, compensation cost				$ 0	$ 400,000
Common stock, shares outstanding including early exercises (in shares)				48,063,761	43,450,819
Options grants in period, weighted average grant date fair value (in dollars per share)					$ 14.95	$ 9.79
Aggregate intrinsic value of employee options exercised				$ 72,300,000	$ 71,900,000	$ 4,400,000
Unrecognized compensation cost related to unvested options				$ 2,500,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option expiration period				10 years
Straight-line basis weighted-average amortization period				1 year 1 month 6 days
Equity award plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (shares)				4,107,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (shares)				848,345
Number of shares available for grant (in shares)	800,000	800,000
Purchase price of common stock, percent of market price		85.00%
Annual increase to shares available for future issuance (in shares)	800,000	800,000
Percentage of common stock outstanding annual increase to shares available for issuance	1.00%	1.00%
Stock purchase offering period		6 months
Participants maximum percentage of annual salary	15.00%	15.00%
Shares purchased during period (in shares)				379,306
Weighted average price of shares purchased (in dollars per share)				$ 24.23
Proceeds from issuance of shares under ESPP				$ 9,200,000
Unrecognized compensation cost				$ 1,300,000
Straight-line basis weighted-average amortization period				4 months 24 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (shares)				6,391,000
Stock-based compensation expense				$ 3,000,000
Unrecognized compensation cost				$ 155,400,000
Straight-line basis weighted-average amortization period				2 years 8 months 12 days
Vested (in shares)				1,609,000	1,607,000
Award requisite service period				2 years
PSUs | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value							$ 2,100,000
Unrecognized compensation cost				$ 1,400,000
Straight-line basis weighted-average amortization period				2 years
RSUs and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate fair value of awards vested				$ 58,900,000	$ 51,200,000
Stock options and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 21,200,000
CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental stock-based compensation expense			$ 6,500,000		$ 1,100,000	$ 7,600,000
2000 Stock Option and Incentive Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price of common stock, percent of market price				100.00%
Outstanding common stock ownership threshold, percentage				10.00%
Purchase price of common stock for executive officers that own more than 10%, percent of market price				110.00%
Option expiration period				10 years
2000 Stock Option and Incentive Plan | Stock options and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized to be added to the Plan (in shares)	12,500,000	12,500,000
Annual increase to shares available for future issuance (in shares)	3,800,000	3,800,000
Percentage of common stock outstanding annual increase to shares available for issuance	5.00%	5.00%
2017 Equity Incentive Plan | Equity award plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (shares)	3,800,000	3,800,000
Redeemable convertible preferred stock warrant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued, price per share (in dollars per share)	$ 25.12	$ 25.12
Issuance of common stock upon exercise of common stock warrants (in shares)		224,691
Common stock warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued, price per share (in dollars per share)					$ 33.36
Issuance of common stock upon exercise of common stock warrants (in shares)					66,661
Warrants to purchase common stock (in shares)				0	83,163
Common stock reserved for issuance (shares)				74
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares converted into common stock (in shares)		25,370,616				24,845,000
Shares issued as stock dividend (in shares)						582,000
Issuance of common stock upon exercise of common stock warrants (in shares)					67,000	280,000
IPO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
IPO price per share (in dollars per share)	$ 22	$ 22

Common Stock and Stockholders_4

Common Stock and Stockholders' Equity - Common Stock Reserved for Issuance (Details) shares in Thousands	Dec. 31, 2019shares
Class of Stock [Line Items]
Common stock reserved for issuance (shares)	13,564
Equity award plans
Class of Stock [Line Items]
Common stock reserved for issuance (shares)	4,107
Stock options | Common stock
Class of Stock [Line Items]
Common stock reserved for issuance (shares)	3,066
Restricted stock units
Class of Stock [Line Items]
Common stock reserved for issuance (shares)	6,391

Common Stock and Stockholders_5

Common Stock and Stockholders' Equity - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Balance beginning of the period (shares)		6,013,000	9,314,000
Granted (shares)			44,000
Exercised (shares)	(425,436)	(2,744,000)	(2,979,000)
Forfeited (shares)		(203,000)	(366,000)
Balance end of the period (shares)		3,066,000	6,013,000	9,314,000
Weighted- Average Exercise Price
Balance beginning of the period (in dollars per share)		$ 11.65	$ 10.63
Granted (in dollars per share)			30.81
Exercised (in dollars per share)		10.41	8.13
Forfeited (in dollars per share)		18.01	16.59
Balance end of the period (in dollars per share)		$ 12.33	$ 11.65	$ 10.63
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Options vested and exercisable at end of period (shares)		2,790,000
Options vested and exercisable at end of period (in dollars per share)		$ 11.55
Balance, Weighted-Average Remaining Contractual Life (Years)		5 years 7 months 6 days	6 years 4 months 24 days	7 years 2 months 12 days
Options vested and exercisable, Weighted Average-Remaining Contractual Life (Years)		5 years 4 months 24 days
Balance, Aggregate Intrinsic Value		$ 62,759	$ 86,624	$ 198,012
Options vested and exercisable at end of period, Aggregate Intrinsic Value		$ 59,282

Common Stock and Stockholders_6

Common Stock and Stockholders' Equity - RSU Activity (Details) - RSUs - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Balance at beginning of period (shares)	5,709	4,216
Granted (shares)	3,145	3,354
RSUs released (in shares)	(1,609)	(1,607)
Forfeited (shares)	(854)	(254)
Balance at end of period (shares)	6,391	5,709	4,216
Weighted- Average Grant Date Fair Value Per Share
Balance at beginning of period (in dollars per share)	$ 28.01	$ 20.57
Granted (in dollars per share)	34.86	30.94
Released (in dollars per share)	26.77	14.78
Forfeited (in dollars per share)	30.45	26.80
Balance at end of period (in dollars per share)	$ 31.37	$ 28.01	$ 20.57
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
Weighted- Average Remaining Contractual Life (Years)	1 year 8 months 12 days	1 year 9 months 18 days	1 year 8 months 12 days
Aggregate Intrinsic Value	$ 209,621	$ 148,389	$ 134,448

Common Stock and Stockholders_7

Common Stock and Stockholders' Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 13,735	$ 13,822	$ 14,065	$ 13,828	$ 13,953	$ 13,018	$ 12,936	$ 13,590	$ 55,450	$ 53,497	$ 42,596
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	3,494	3,040	2,691	3,078	2,688	2,613	2,513	2,347	12,303	10,161	6,213
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	5,684	6,330	7,198	6,486	6,804	6,165	5,850	6,180	25,698	24,999	14,451
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	3,481	3,508	3,196	3,337	3,578	3,458	3,796	4,237	13,522	15,069	19,538
License | Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	99	75	89	83	79	67	54	53	346	253	103
Subscription | Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	484	454	470	443	418	349	371	379	1,851	1,517	1,089
Professional services | Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 493	$ 415	$ 421	$ 401	$ 386	$ 366	$ 352	$ 394	$ 1,730	$ 1,498	$ 1,202

Common Stock and Stockholders_8

Common Stock and Stockholders' Equity - Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)	$ 0
Risk-free interest rate	0.00%
Risk-free interest rate, minimum		2.40%	1.90%
Risk-free interest rate, maximum		2.80%	2.20%
Expected term (in years)	0 years	6 years 1 month 6 days
Volatility	0.00%	48.00%
Volatility, minimum			46.00%
Volatility, maximum			49.00%
Dividend yield	0.00%	0.00%	0.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)			$ 25.12
Risk-free interest rate			1.40%
Risk-free interest rate, minimum	1.60%	2.14%
Risk-free interest rate, maximum	2.40%	2.52%
Expected term (in years)	6 months	6 months	6 months
Volatility			30.00%
Volatility, minimum	35.00%	30.00%
Volatility, maximum	40.00%	43.00%
Dividend yield	0.00%	0.00%	0.00%
Minimum | Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)		$ 29.92	$ 16.73
Expected term (in years)			6 years
Minimum | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)	$ 33.69	24.65
Maximum | Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)		30.97	$ 31.16
Expected term (in years)			6 years 1 month 6 days
Maximum | Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock (in dollars per share)	$ 35.03	$ 31

Income Taxes - Schedule of Loss

Income Taxes - Schedule of Loss Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Domestic									$ (108,234)	$ (85,252)	$ (82,292)
Foreign									8,420	13,361	3,411
Loss before income taxes	$ (19,243)	$ (16,766)	$ (30,264)	$ (33,541)	$ (16,938)	$ (7,952)	$ (19,933)	$ (27,068)	$ (99,814)	$ (71,891)	$ (78,881)

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Federal									$ 14	$ 1	$ 17
State									93	56	50
Foreign									23,857	3,263	1,788
Total current									23,964	3,320	1,855
Deferred
Foreign									(5,243)	(375)	(16)
Total deferred									(5,243)	(375)	(16)
Total	$ 767	$ 16,747	$ 496	$ 711	$ 1,010	$ 334	$ 473	$ 1,128	$ 18,721	$ 2,945	$ 1,839

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Federal and state net operating losses	$ 91,529	$ 59,803
Research/other credits	3,898	2,913
Non-deductible and accrued expenses	2,780	4,756
Deferred revenue	16,576	14,040
Property and equipment	430	506
Stock-based compensation	10,363	10,323
Lease liability	6,560	0
Other	705	1,024
Gross deferred tax assets	132,841	93,365
Valuation allowance	(112,882)	(83,376)
Net deferred tax assets	19,959	9,989
Deferred tax liabilities:
Acquired intangible assets	(3,807)	(4,117)
Right of use asset	(4,738)	0
Property and equipment	(8,684)	(8,691)
Others	(27)	(116)
Net deferred tax liabilities	(17,256)	(12,924)
Total	$ 2,703
Total		$ (2,935)

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax at federal statutory rate									$ (20,972)	$ (15,097)	$ (30,385)
State, net of federal benefit									92	61	60
Meals and entertainment disallowance									835	799	365
Stock-based compensation									(7,852)	(6,215)	4,097
Non-deductible warrant expenses									0	0	272
Tax Reform federal rate change									0	0	36,460
Impact of intangible property transfer									20,551	0	0
Change in valuation allowance									25,874	23,929	(10,512)
Other									193	(532)	1,482
Total	$ 767	$ 16,747	$ 496	$ 711	$ 1,010	$ 334	$ 473	$ 1,128	$ 18,721	$ 2,945	$ 1,839

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Increase in the deferred tax asset valuation allowance	$ 29,500	$ 29,100
Tax reform federal rate change	0	0	$ 36,460
Accrual for uncertain tax positions related to the completion of an intra-group transfer of certain intellectual property rights	20,816	195	845
Expected reduction in the amount of unrecognized tax benefits within the next 12 months	900
Settlements with taxing authorities	0	0	416
Unrecognized tax benefits that, if recognized, would impact the effective tax rate	21,300	1,100	1,400
State and Local Tax Authorities | California
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	36,600
State and Local Tax Authorities | California | Research
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	1,500
State and Local Tax Authorities | Other States
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	168,100
State and Local Tax Authorities | Texas | Research
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	300
Foreign Tax Authority | Israel Tax Authority
Operating Loss Carryforwards [Line Items]
Settlements with taxing authorities			$ 400
Increase in income taxes payable		$ 400
Federal Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	378,600
Federal Tax Authority | Research
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 2,400

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at the beginning of the period	$ 1,267	$ 1,727	$ 1,050
Additions for tax positions taken in prior years	64	104	248
Additions for tax positions taken in current year	20,816	195	845
Reductions for tax positions taken in prior years	0	(759)	0
Settlements with taxing authorities	0	0	(416)
Statute of limitation expirations	(104)	0	0
Unrecognized tax benefits at the end of the period	$ 22,043	$ 1,267	$ 1,727

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net loss	$ (20,010)	$ (33,513)	$ (30,760)	$ (34,252)	$ (17,948)	$ (8,286)	$ (20,406)	$ (28,196)	$ (118,535)	$ (74,836)	$ (80,720)
Deemed dividend on the conversion of Series G redeemable convertible preferred stock									0	0	12,810
Net loss attributable to common stockholders									$ (118,535)	$ (74,836)	$ (93,530)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (in shares)	47,511	46,584	45,494	44,196	43,016	42,064	40,457	38,313	45,957	40,980	11,405
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.42)	$ (0.72)	$ (0.68)	$ (0.78)	$ (0.42)	$ (0.20)	$ (0.50)	$ (0.74)	$ (2.58)	$ (1.83)	$ (8.20)

Net Loss Per Share - Securities

Net Loss Per Share - Securities Excluded from Diluted Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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)	3,066	6,013	9,314
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)	0	47	146
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)	6,391	5,709	4,216
Shares estimated under ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	196	233	221
Warrants to purchase common stock | Common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of diluted net loss per share (shares)	0	0	83

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Estimated accrued severance benefits, noncurrent liability	$ 3,000,000	$ 2,500,000
Deposits in severance pay fund	$ 2,400,000	2,000,000
Company percent of match	50.00%
Employee percent contributed for company match	6.00%
Maximum matching dollar amount	$ 2,000
Matching contributions vesting percentage	100.00%
Company contributions to the 401(k)	$ 1,400,000	$ 1,300,000	$ 1,100,000

Segment Information - Narrative

Segment Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2019business_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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 91,331	$ 91,622	$ 78,280	$ 75,568	$ 84,732	$ 85,628	$ 67,594	$ 59,697	$ 336,801	$ 297,651	$ 224,404
Total Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									248,145	222,205	171,262
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									236,878	215,322	165,140
Other Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									11,267	6,883	6,122
Europe, Middle East, and Africa (“EMEA”)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									54,228	52,214	36,664
Asia Pacific and Japan (“APJ”)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 34,428	$ 23,232	$ 16,478

Segment Information - Long-live

Segment Information - Long-lived Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 23,835	$ 24,349
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	18,598	18,570
Israel
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	4,370	5,057
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 867	$ 722

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jun. 05, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Deferred revenue	$ 188,907		$ 172,031	$ 135,867
Director
Related Party Transaction [Line Items]
Deferred revenue	$ 600
Performance Stock Units (PSUs) | Director
Related Party Transaction [Line Items]
Grant date fair value		$ 2,100
Recognition period	2 years
Unrecognized compensation cost	$ 1,400
License | Director
Related Party Transaction [Line Items]
Revenue from related party sales	1,400
Subscription | Director
Related Party Transaction [Line Items]
Revenue from related party sales	$ 100

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) - Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Revenue	$ 91,331	$ 91,622	$ 78,280	$ 75,568	$ 84,732	$ 85,628	$ 67,594	$ 59,697	$ 336,801	$ 297,651	$ 224,404
Cost of revenue:
Cost of revenue	21,025	21,697	17,456	19,000	17,486	19,197	14,713	16,486	79,178	67,882	58,612
Total gross profit	70,306	69,925	60,824	56,568	67,246	66,431	52,881	43,211	257,623	229,769	165,792
Operating expenses:
Research and development	24,302	20,556	19,440	18,497	17,161	15,062	14,803	14,687	82,795	61,713	47,435
Sales and marketing	49,915	51,035	56,173	55,923	50,464	46,098	45,039	42,279	213,046	183,880	144,398
General and administrative	15,649	15,318	15,838	16,213	16,849	13,880	13,260	13,732	63,018	57,721	51,206
Total operating expenses	89,866	86,909	91,451	90,633	84,474	75,040	73,102	70,698	358,859	303,314	243,039
Loss from operations	(19,560)	(16,984)	(30,627)	(34,065)	(17,228)	(8,609)	(20,221)	(27,487)	(101,236)	(73,545)	(77,247)
Interest expense	(105)	(156)	(142)	(93)	(237)	(208)	(225)	(243)	(496)	(913)	(1,223)
Other income, net	422	374	505	617	527	865	513	662	1,918	2,567	316
Loss before income taxes	(19,243)	(16,766)	(30,264)	(33,541)	(16,938)	(7,952)	(19,933)	(27,068)	(99,814)	(71,891)	(78,881)
Income tax provision	767	16,747	496	711	1,010	334	473	1,128	18,721	2,945	1,839
Net loss	$ (20,010)	$ (33,513)	$ (30,760)	$ (34,252)	$ (17,948)	$ (8,286)	$ (20,406)	$ (28,196)	$ (118,535)	$ (74,836)	$ (80,720)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.42)	$ (0.72)	$ (0.68)	$ (0.78)	$ (0.42)	$ (0.20)	$ (0.50)	$ (0.74)	$ (2.58)	$ (1.83)	$ (8.20)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted (in shares)	47,511	46,584	45,494	44,196	43,016	42,064	40,457	38,313	45,957	40,980	11,405
License
Revenue:
Revenue	$ 48,401	$ 50,203	$ 38,831	$ 37,680	$ 47,482	$ 51,082	$ 34,323	$ 29,780	$ 175,115	$ 162,667	$ 125,348
Cost of revenue:
Cost of revenue	8,180	9,892	5,622	7,607	6,852	8,947	4,919	7,136	31,301	27,854	23,841
Subscription
Revenue:
Revenue	37,586	36,570	34,822	33,799	32,888	30,339	28,986	26,359	142,777	118,572	86,691
Cost of revenue:
Cost of revenue	5,795	5,376	5,599	5,207	4,613	4,069	3,732	3,801	21,977	16,215	13,912
Professional services
Revenue:
Revenue	5,344	4,849	4,627	4,089	4,362	4,207	4,285	3,558	18,909	16,412	12,365
Cost of revenue:
Cost of revenue	$ 7,050	$ 6,429	$ 6,235	$ 6,186	$ 6,021	$ 6,181	$ 6,062	$ 5,549	$ 25,900	$ 23,813	$ 20,859

Selected Quarterly Financial _4

Selected Quarterly Financial Data (Unaudited) - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 13,735	$ 13,822	$ 14,065	$ 13,828	$ 13,953	$ 13,018	$ 12,936	$ 13,590	$ 55,450	$ 53,497	$ 42,596
Cost of revenue | License
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	99	75	89	83	79	67	54	53	346	253	103
Cost of revenue | Subscription
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	484	454	470	443	418	349	371	379	1,851	1,517	1,089
Cost of revenue | Professional services
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	493	415	421	401	386	366	352	394	1,730	1,498	1,202
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	3,494	3,040	2,691	3,078	2,688	2,613	2,513	2,347	12,303	10,161	6,213
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	5,684	6,330	7,198	6,486	6,804	6,165	5,850	6,180	25,698	24,999	14,451
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,481	$ 3,508	$ 3,196	$ 3,337	$ 3,578	$ 3,458	$ 3,796	$ 4,237	$ 13,522	$ 15,069	$ 19,538

Subsequent Event (Details)

Subsequent Event (Details)	Feb. 06, 2020$ / shares
Ferrari Group Holdings | Forescout Technologies | Subsequent Event
Business Acquisition [Line Items]
Business Acquisition, Share Price	$ 33