Varonis Systems (VRNS) 10-K 13 Feb 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Feb. 09, 2018	Jun. 30, 2017
Document Information [Line Items]
Entity Registrant Name	VARONIS SYSTEMS INC
Entity Central Index Key	1,361,113
Trading Symbol	vrns
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		28,157,995
Entity Public Float			$ 977.1
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 56,689	$ 48,315
Short-term investments	79,868	65,493
Trade receivables (net of allowance for doubtful accounts of $ 433 and $ 372 at December 31, 2017 and at December 31, 2016, respectively)	75,596	53,861
Prepaid expenses and other current assets	7,130	3,650
Total current assets	219,283	171,319
Long-term assets:
Other assets	973	609
Property and equipment, net	11,896	9,910
Total long-term assets	12,869	10,519
Total assets	232,152	181,838
Current liabilities:
Trade payables	635	1,288
Accrued expenses and other short term liabilities	42,453	28,479
Deferred revenues	73,891	58,478
Total current liabilities	116,979	88,245
Long-term liabilities:
Deferred revenues	7,034	3,562
Other liabilities	6,561	7,292
Total long-term liabilities	13,595	10,854
Stockholders’ equity:
Common stock of $ 0.001 par value—Authorized: 200,000,000 shares at December 31, 2017 and 2016; Issued and outstanding: 28,146,162 shares at December 31, 2017 and 26,821,762 shares at December 31, 2016	28	27
Accumulated other comprehensive income (loss)	136	(479)
Additional paid-in capital	223,868	189,335
Accumulated deficit	(122,454)	(106,144)
Total stockholders’ equity	101,578	82,739
Total liabilities and stockholders’ equity	$ 232,152	$ 181,838

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts	$ 433	$ 372
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	28,146,162	26,821,762
Common stock, outstanding (in shares)	28,146,162	26,821,762

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Licenses	$ 123,610	$ 92,873	$ 71,273
Maintenance and services	93,754	71,583	55,937
Total revenues	217,364	164,456	127,210
Cost of revenues	20,873	15,843	12,019
Gross profit	196,491	148,613	115,191
Operating costs and expenses:
Research and development	47,369	36,660	31,792
Sales and marketing	135,896	107,825	86,367
General and administrative	26,823	19,822	16,106
Total operating expenses	210,088	164,307	134,265
Operating loss	(13,597)	(15,694)	(19,074)
Financial income (expenses), net	2,362	(885)	(1,523)
Loss before income taxes	(11,235)	(16,579)	(20,597)
Income taxes	(2,459)	(1,131)	(686)
Net loss	$ (13,694)	$ (17,710)	$ (21,283)
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.50)	$ (0.67)	$ (0.84)
Weighted average number of shares used in computing net loss per share of common stock, basic and diluted (in shares)	27,467,440	26,406,312	25,198,546

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net loss	$ (13,694)	$ (17,710)	$ (21,283)
Other comprehensive income (loss):
Unrealized losses on short-term investments	(27)
Unrealized gains (losses) on derivative instruments	642	(148)	(5)
Total other comprehensive income (loss)	615	(148)	(5)
Comprehensive loss	$ (13,079)	$ (17,858)	$ (21,288)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]		Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2014	24,685,604
Balance at Dec. 31, 2014	$ 25		$ 162,478	$ (326)	$ (67,151)	$ 95,026
Stock-based compensation expense			7,794			$ 7,794
Exercise of stock options (in shares)	1,350,162					1,334,351
Exercise of stock options	$ 1		2,054			$ 2,055
Exercise of restricted stock units (in shares)	33,388
Exercise of restricted stock units		[1]
Unrealized gains (losses) on derivative instruments				(5)		(5)
Net loss					(21,283)	(21,283)
Unrealized losses on short-term investments
Balance (in shares) at Dec. 31, 2015	26,069,154
Balance at Dec. 31, 2015	$ 26		172,326	(331)	(88,434)	83,587
Stock-based compensation expense			12,938			$ 12,938
Exercise of stock options (in shares)						445,535
Unrealized gains (losses) on derivative instruments				(148)		$ (148)
Net loss					(17,710)	(17,710)
Common stock issued under employee stock plans, net (in shares)	752,608
Common stock issued under employee stock plans, net	$ 1		4,071			4,072
Unrealized losses on short-term investments
Balance (in shares) at Dec. 31, 2016	26,821,762
Balance at Dec. 31, 2016	$ 27		189,335	(479)	(106,144)	82,739
Effect of adoption of ASU 2016-09 | Accounting Standards Update 2016-09 [Member]			2,616		(2,616)
Stock-based compensation expense			19,835			$ 19,835
Exercise of stock options (in shares)						832,270
Unrealized gains (losses) on derivative instruments				642		$ 642
Net loss					(13,694)	(13,694)
Common stock issued under employee stock plans, net (in shares)	1,324,400
Common stock issued under employee stock plans, net	$ 1		12,082			12,083
Unrealized losses on short-term investments				(27)		(27)
Balance (in shares) at Dec. 31, 2017	28,146,162
Balance at Dec. 31, 2017	$ 28		$ 223,868	$ 136	$ (122,454)	$ 101,578
[1]	Represents an amount lower than $ 1.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net loss	$ (13,694)	$ (17,710)	$ (21,283)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	3,328	2,180	1,615
Stock-based compensation	19,835	12,938	7,794
Capital gain from disposal of fixed assets	(20)	(2)	(4)
Changes in assets and liabilities:
Trade receivables	(21,735)	(6,425)	(9,567)
Prepaid expenses and other current assets	(3,317)	(1,028)	796
Trade payables	(653)	(1,324)	(91)
Accrued expenses and other short term liabilities	14,453	5,302	6,270
Deferred revenues	18,885	13,269	11,554
Other long term liabilities	(731)	147	187
Net cash provided by (used in) operating activities	16,351	7,347	(2,729)
Cash flows from investing activities:
Increase in short-term investments	(14,402)	(8,390)	(22,001)
Decrease (increase) in long-term deposits	(305)	(111)	11
Proceeds from sale of property and equipment	20	2	4
Purchase of property and equipment	(5,314)	(3,825)	(4,536)
Net cash used in investing activities	(20,001)	(12,324)	(26,522)
Cash flows from financing activities:
Proceeds from employee stock plans, net	12,083	4,072	2,055
Net cash provided by financing activities	12,083	4,072	2,055
Increase (decrease) in cash, cash equivalents and restricted cash	8,433	(905)	(27,196)
Cash, cash equivalents and restricted cash at beginning of period	48,803	49,708	76,904
Cash, cash equivalents and restricted cash at end of period	57,236	48,803	49,708
Supplemental disclosures of non-cash flow information
Deferred rent fixed asset additions		583	1,355
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 285	$ 246	$ 354

Note 1 - General

Note 1 - General	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	NOTE 1: Varonis Systems, Inc. (“VSI” and together with its subsidiaries, collectively, the “Company”) was incorporated under the laws of the State of Delaware on November 3, 2004 January 1, 2005. VSI has seven November 24, 2004; March 14, 2007; July 6, 2011; (“VSF February 22, 2012; February 19, 2013; November 11, 2016; February 28, 2017. The Company’s software products and services allow enterprises to manage, analyze and secure enterprise data. Varonis focuses on protecting enterprise data: sensitive files and emails; confidential customer, patient and employee data; financial records; strategic and product plans; and other intellectual property. Through its products DatAdvantage (including DatAlert, the Automation Engine and Varonis Edge), DataPrivilege, Data Classification Engine (including GDPR Patterns), Data Transport Engine, DatAnswers and DatAnywhere, the software platform allows enterprises to protect sensitive data from insider threats and cyberattacks, and realize the value of their enterprise data in ways that are not VSI markets and sells products and services mainly in the United States. VSUK, VSG, VSF, VSC, VIRE and VAUS resell the Company’s products and services mainly in the UK, Germany, France and rest of Europe, Canada, Ireland and Australia, respectively. The Company primarily sells its products and services to a global network of distributors and Value Added Resellers (VARs), which sell the products to end user customers.

Note 2 - Significant Accounting

Note 2 - Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Significant Accounting Policies [Text Block]	NOTE 2: The consolidated financial statements are prepared according to United States generally accepted accounting principles (“U.S. GAAP”), applied on a consistent basis, as follows: a. Use of Estimates: The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates, judgments and assumptions. The Company’s management believes that the estimates, judgments and assumptions used are reasonable based upon information available at the time they are made. These estimates, judgments and assumptions can affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the dates of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. On an ongoing basis, the Company’s management evaluates estimates, including those related to accounts receivable and sales allowances, fair values of stock-based awards, deferred taxes and income tax uncertainties, and contingent liabilities. Such estimates are based on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. b. Financial Statements in U.S. Dollars: Most of the revenues and costs of VSI are denominated in United States dollars (“dollars”). Some of the subsidiaries’ revenues and costs are primarily incurred in Euros, the Pound Sterling, Canadian dollars, Australian dollars and NIS; however, the Company’s management believes that the dollar is the primary currency of the economic environment in which VSI and each of its subsidiaries operate. Thus, the dollar is the Company’s functional and reporting currency. Accordingly, transactions denominated in currencies other than the functional currency are re-measured to the functional currency in accordance with ASC No. 830, c. Principles of Consolidation: The consolidated financial statements include the accounts of VSI and its wholly-owned subsidiaries, VSL, VSUK, VSG, VSF, VSC, VIRE and VAUS. All intercompany transactions and balances have been eliminated upon consolidation. d. Cash, Cash Equivalents and Short-Term Investments: The Company accounts for investments in marketable securities in accordance with ASC No. 320, three The Company considers all high quality investments purchased with original maturities at the date of purchase greater than three may one As of December 31, 2017 Amortized Gross Gross Fair Cash and cash equivalents Cash $ 49,819 $ - $ - $ 49,819 Money market funds 6,870 - - 6,870 Total $ 56,689 $ - $ - $ 56,689 Short-term investments US Treasury securities $ 39,758 $ *) $ (27 ) $ 39,731 Term bank deposits 40,137 - - 40,137 Total $ 79,895 $ - $ (27 ) $ 79,868 *) Represents an amount lower than $1. All the US Treasury securities in short-term investments have a stated effective maturity of less than 12 December 31, 2017. As of December 31, 2016 Amortized Gross Gross Fair Cash and cash equivalents Cash $ 42,175 $ - $ - $ 42,175 Money market funds 6,140 - - 6,140 Total $ 48,315 $ - $ - $ 48,315 Short-term investments Term bank deposits $ 65,493 - - $ 65,493 Total $ 65,493 $ - $ - $ 65,493 The gross unrealized loss related to these short-term investments was due primarily to changes in interest rates. The Company reviews its short-term investments on a regular basis to evaluate whether or not not one not December 31, 2017, not A short-term bank deposit is a deposit with a maturity of more than three one 0.60% 1.35% 0.55% 1.11%, December 31, 2017 2016, 0.03% 0.15% December 31, 2017 2016, e. Restricted Cash: Restricted cash is primarily invested in certificates of deposit and is used mostly as security for the Company’s lease commitments. The Company had no December 31, 2017 2016, $547 $488 December 31, 2017 2016, f. Property and Equipment: Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets at the following annual rates: % Computer equipment 33 Office furniture and equipment 14 - 15 Leasehold improvements Over the shorter of the expected lease g. Impairment of Long-Lived Assets: The Company’s long-lived assets are reviewed for impairment in accordance with ASC No. 360 may not December 31, 2017, 2016 2015, no h. Long-Term Lease Deposits: Long-term lease deposits include long-term deposits for offices. i. Revenue Recognition: The Company generates revenues in the form of software license fees and related maintenance and services fees. Maintenance and services primarily consist of fees for maintenance services (including support and unspecified upgrades and enhancements when and if they are available) and professional services (including training) that are not The Company accounts for the sale of perpetual software in accordance with ASC No. 985 605, 985 605, 985 605 The Company determines the fair value based on the stand alone sales price charged for maintenance, and professional services. The Company has defined classes of transactions, based on the value of licensed software products purchased from the Company. The Company prices renewals for each class of transaction as a fixed percentage of the total gross value of licensed software products the customer purchased. Software license revenues are recognized when persuasive evidence of an arrangement exists, the software license has been delivered, there are no no not The Company recognizes revenues from the sale of term license arrangements, ratably, on a straight-line basis, over the term of the underlying contract, and is typically up to one The Company recognizes revenues from maintenance ratably over the term of the underlying maintenance contract term. The term of the maintenance contract is usually one Revenues from professional services consist mostly of time and material services and, accordingly, are generally recognized as the services are performed or when the service term has expired. Professional services bundled with licensed software and other software related elements are not Deferred revenues represent mostly unrecognized fees billed or collected for maintenance and professional services. The Company does not one December 31, 2017, 2016 2015, no j. Cost of Revenues: Cost of revenues consists of the cost of maintenance and services, resulting from costs associated with support, and professional services. k. Accounting for Stock-Based Compensation: The Company accounts for stock-based compensation in accordance with ASC No. 718, No. 718 The Company recognizes compensation expenses for the value of its awards granted based on the straight-line method over the requisite service period of each of the awards. The Company applies ASC 718 505 50, 505 50. The Company selected the Black-Scholes-Merton option pricing model as the most appropriate fair value method for its stock options awards, whereas the fair value of restricted stock units is based on the market value of the underlying shares at the date of grant. The fair value of options granted to employees and non-employee directors is estimated at the date of grant using the following weighted average assumptions: For the year ended December 31, 2017, no December 31, 2016 2015, 0%, 62.1% 65.0%, 1.42% 1.94% 2.00%, 6.25. The Company used its historical volatility in accordance with ASC 718. 110, zero no may not no The non-cash compensation expenses related to employees and consultants for the years ended December 31, 2017, 2016 2015 $19,835, $12,938 $7,794, Effective as of January 1, 2017, 2016 09, 718 2016 09” 2016 09 not 2016 09, $2,616 January 1, 2017. ASU 2016 09 $7,131 $718 December 31, 2016, 2016 09, 2016 09 January 1, 2017. January 1, 2017 no January 1, 2017. Additionally, ASU 2016 09 l. Research and Development Costs: Research and development costs are charged to the statement of operations as incurred. ASC No. 985 20, Based on the Company’s product development process, technological feasibility is established upon the completion of a working model. The Company does not m. Income Taxes: The Company accounts for income taxes in accordance with ASC No. 740, not ASC 740 two first not second 50% n. Derivative Instruments: The Company’s primary objective for holding derivative instruments is to reduce its exposure to foreign currency rate changes. The Company reduces its exposure by entering into forward foreign exchange contracts with respect to operating expenses that are forecast to be incurred in currencies other than the U.S. dollar. A majority of the Company’s revenues and operating expenditures are transacted in U.S. dollars. However, certain operating expenditures are incurred in or exposed to other currencies, primarily the NIS. The Company has established forecasted transaction currency risk management programs to protect against fluctuations in fair value and the volatility of future cash flows caused by changes in exchange rates. The Company’s currency risk management program includes forward foreign exchange contracts designated as cash flow hedges. These forward foreign exchange contracts generally mature within 12 not Derivative instruments measured at fair value and their classification on the consolidated balance sheets are presented in the following table (in thousands): Assets as of Liabilities as of Notional Fair Notional Fair Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships—included in other current assets and accrued expenses and other short term liabilities $ 1,746 $ 163 $ 46,116 $ (479 ) For the years ended December 31, 2017 2016, $2,649 $332, no December 31, 2017 2016. o. Concentrations of Credit Risks: Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and trade receivables. The Company’s cash, cash equivalents and short-term investments are invested in major banks mainly in the United States but also in the United Kingdom, France, Germany, Israel, Canada, Ireland and Australia. Such deposits in the United States may not The Company’s trade receivables are geographically diversified and derived primarily from sales to a network of distributors and VARs mainly in the United States and Europe. Concentration of credit risk with respect to trade receivables is limited by credit limits, ongoing credit evaluation and account monitoring procedures. The Company performs ongoing credit evaluations of its channel partners and establishes an allowance for doubtful accounts based upon a specific review of all significant outstanding invoices. The Company writes off receivables when they are deemed uncollectible and having exhausted all collection efforts. p. Retirement and Severance Pay: VSI makes available to its employees a retirement plan (the “U.S. Plan”) that qualifies as a deferred salary arrangement under Section 401 1986, may 100% 3% 50% 3% 5% may 80% Pursuant to Israel’s Severance Pay Law, Israeli employees are entitled to severance pay equal to one 14 1963 14” 8.33% 14 not The Company’s liability for severance pay for the employees of its French subsidiary is calculated pursuant to French law, according to which French employees are entitled to an indemnity (a statutory redundancy). The law provides for the payment of severance payment to any employee working for the French subsidiary for at least a year. VSUK makes available to certain eligible employees a pension plan whereby participants in the plan may 100% 3% Total Company expenses related to retirement and severance pay amounted to $4,801, $3,775 $3,085 December 31, 2017, 2016 2015, December 31, 2017 2016 $1,781 $1,664, q. Fair Value of Financial Instruments: Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three • Level 1: • Level 2: not • Level 3: The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The carrying amounts of cash and cash equivalents, trade receivables, short-term investments and trade payables approximate their fair value due to the short-term maturity of such instruments. r. Basic and Diluted Net Loss Per Share: Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential shares of common stock, including stock options, to the extent dilutive. Basic and diluted net loss per share was the same for each period presented as the inclusion of all potential shares of common stock outstanding would have been anti-dilutive. s. Contingent Liabilities: The Company accounts for its contingent liabilities in accordance with ASC No. 450 With respect to legal matters, provisions are reviewed and adjusted to reflect the impact of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter. As of December 31, 2017 2016, not t. Reclassification: Certain amounts in prior years' financial statements have been reclassified to conform to the current year's presentation. u. Recently Issued Accounting Pronouncements: In May 2014, No. 2014 09, and issued subsequent amendments to the initial guidance in March 2016, April 2016, May 2016 December 2016 2016 08, 2016 10, 2016 12 2016 20, not 2014 09 December 15, 2016 may July 9, 2015, one 2014 09. December 15, 2017 January 1, 2018 The most significant impact of the new standard relates to the way the Company accounts for term agreements and commission expense. Specifically, under the current revenue standard, the Company recognizes both the term license and maintenance revenues ratably over the contract period whereas under the new revenue standard it would recognize term license revenues upfront and the associated maintenance revenues over the contract period. The Company has also considered the impact of the guidance in ASC 340 40, 340 40, may not Adoption of the standard will result in a reduction of revenues of $1,974 December 31, 2017 $1,407 December 31, 2016, $9,865 $97, December 31, 2017, January 1, 2016 $5,583. Adoption of the standard related to revenue recognition had no Select recast financial statement information, which reflects the preliminary effect of the adoption of this standard, is set forth below. Year ended As Reported Adjustments Recast for Adoption Total revenues $ 217,364 $ (1,974 ) $ 215,390 Operating loss $ (13,597 ) $ 178 $ (13,419 ) Income taxes $ (2,459 ) $ (328 ) $ (2,787 ) Net loss $ (13,694 ) $ (151 ) $ (13,845 ) Year ended As Reported Adjustments Recast for Adoption Total revenues $ 164,456 $ 1,407 $ 165,863 Operating loss $ (15,694 ) $ 3,699 $ (11,995 ) Income taxes $ (1,131 ) $ (182 ) $ (1,313 ) Net loss $ (17,710 ) $ 3,517 $ (14,193 ) December 31, 2017 Balance Sheet Data As Reported Adjustments Recast for Adoption Assets Current assets: Prepaid expenses and other current assets $ 7,130 $ 9,865 $ 16,995 Liabilities and stockholders’ equity Current liabilities: Accrued expenses and other short term liabilities $ 42,453 $ 1,014 $ 43,467 Deferred revenues $ 73,891 $ (227 ) $ 73,664 Long-term liabilities: Deferred revenues $ 7,034 $ 130 $ 7,164 In January 2016, 2016 13, 2016 13 January 1, 2020, In February 2016, 2016 02, not 12 12 842 840, December 15, 2018, In November 2016, 2016 18, 230 December 15, 2017. December 31, 2017 The following table provides a reconciliation of cash and cash equivalents, and long term restricted cash reported within the consolidated balance sheets that sum to the total of such amounts in the consolidated statements of cash flows: December 31. December 31. December 31. Cash and cash equivalents $ 56,689 $ 48,315 $ 49,241 Long term restricted cash included in other assets 547 488 467 Cash, cash equivalents and long term restricted cash shown in the consolidated statement of cash flows $ 57,236 $ 48,803 $ 49,708 In January 2018, No. 118, not 9 not

Note 3 - Prepaid Expenses and O

Note 3 - Prepaid Expenses and Other Current Assets	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Prepaid Expenses and Other Current Assets [Text Block]	NOTE 3: December 31, 2017 2016 Prepaid expenses $ 6,044 $ 2,871 Government institutions & other receivables 542 369 Deferred charges - 256 Foreign currency forward contracts derivatives 163 - Short-term deposits 374 122 Other 7 32 $ 7,130 $ 3,650

Note 4 - Property and Equipment

Note 4 - Property and Equipment, Net	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	NOTE 4: December 31, 2017 2016 Cost: Computer equipment $ 8,473 $ 7,800 Office furniture and equipment 2,263 2,094 Leasehold improvements 9,163 7,459 19,899 17,353 Accumulated depreciation 8,003 7,443 Property and equipment, net $ 11,896 $ 9,910 Depreciation expenses for the years ended December 31, 2017, 2016 2015 $3,328, $2,180 $1,615,

Note 5 - Accrued Expenses and O

Note 5 - Accrued Expenses and Other Short Term Liabilities	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]	NOTE 5: December 31, 2017 2016 Employees $ 17,748 $ 12,306 Accrued expenses 9,507 6,777 Government authorities and other 14,006 8,293 Foreign exchange forward contract derivatives - 479 Other short term liabilities 1,192 624 $ 42,453 $ 28,479

Note 6 - Commitments and Contin

Note 6 - Commitments and Contingent Liabilities	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	NOTE 6: a. Liens: The Company has several liens granted to financial institutions mainly to secure various operating lease agreements in connection with its office space. b. Lease Commitments: The Company rents its facilities in all locations under operating leases with lease periods expiring from 2018 2026. 2018 2020. Aggregate minimum rental commitments under non-cancelable leases as of December 31, 2017 Payments Due By 2018 $ 6,418 2019 5,561 2020 4,335 2021 4,561 2022 4,587 Thereafter 21,063 $ 46,525 Total rent expenses for the years ended December 31, 2017, 2016 2015 $4,075, $3,258 $4,296, December 31, 2017 $732. For leases that contain predetermined fixed escalations of the minimum rent, the Company recognizes the related rent expense on a straight-line basis from the date of possession of the property to the end of the initial lease term. The Company records any differences between the straight-line rent amounts and amounts payable under the leases as part of deferred rent, in accrued liabilities or long-term liabilities, as appropriate. Cash or lease incentives received upon entering into certain leases (“tenant allowances”) are recognized on a straight-line basis as a reduction to rent from the date of possession of the property through the end of the initial lease term. The Company records the unamortized portion of tenant allowances as a part of deferred rent, in current liabilities or other long-term liabilities, as appropriate. As of December 31, 2017 2016, $941 $624, $4,780 $5,377, On March 31, 2014, may $7,000 0.15%, not 4.10%. December 31, 2017, 4.35%. among other things, may August 15, 2018 December 31, 2017, no

Note 7 - Fair Value Measurement

Note 7 - Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Fair Value Disclosures [Text Block]	N OTE 7: The following table sets forth the Company’s liabilities that were measured at fair value as of December 31, 2017 2016 As of December 31, 2017 As of December 31, 2016 Level I Level II Level Fair Level I Level II Level Fair Financial assets: Cash equivalents: Money market funds 6,870 – – 6,870 6,140 – – 6,140 Short-term investments: US Treasury securities 39,731 – – 39,731 – – – – Term bank deposits 40,137 – – 40,137 65,493 – – 65,493 Other current assets: Forward foreign exchange contracts – 163 – 163 – – – – Financial liabilities: Forward foreign exchange contracts – – – – – (479 ) – (479 ) Total financial assets (liabilities) $ 86,738 $ 163 $ – $ 86,901 $ 71,633 $ (479 ) $ – $ 71,154

Note 8 - Stockholders' Equity

Note 8 - Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	NOTE 8: a. Composition of common stock capital: Authorized Issued and outstanding Number of shares December 31, December 31, 2017 2016 2017 2016 Stock of $0.001 par value: Common stock 200,000,000 200,000,000 28,146,162 26,821,762 b. Common stock rights: The Company’s Amended and Restated Certificate of Incorporation authorizes the Company to issue 200,000,000 $0.001 The common stock confers upon its holders the right to participate in the general meetings of the Company, to vote at such meetings (each share represents one c. Stock option plans: On December 30, 2005, 2005 “2005 December 31, 2013, 4,713,319 four No 2005 December 31, 2013, no 2005 On November 14, 2013, 2013 “2013 1,904,633 2013 2013 January 1, 2016 January 1 four 4% December 31 2013 five 5% December 31. January 1, 2018, 2017 2016, 2013 1,125,846, 1,072,870 1,042,766 2013 four 2013 A summary of employees’ stock options activities during the year ended December 31, 2017 Year ended Number Weighted Aggregate Weighted Options outstanding at the beginning of the year 2,388,348 $ 15.243 $ 30,025 5.861 Granted - $ - Exercised (832,270 ) $ 13.031 Forfeited (99,793 ) $ 19.930 Options outstanding at the end of the period 1,456,285 $ 16.172 $ 47,152 4.906 Vested and expected to vest 1,456,285 $ 16.172 $ 47,152 4.906 Options exercisable at the end of the period 1,262,206 $ 15.052 $ 42,282 4.595 A summary of employees’ stock options activities during the years ended December 31, 2016 2015 Year ended Number Weighted Aggregate Weighted Options outstanding at the beginning of the year 2,782,560 $ 14.026 $ 21,337 6.246 Granted 135,000 $ 16.870 Exercised (445,535 ) $ 5.901 Forfeited (83,677 ) $ 27.126 Options outstanding at the end of the period 2,388,348 $ 15.243 $ 30,025 5.861 Vested and expected to vest 2,331,800 $ 15.074 $ 29,689 5.806 Options exercisable at the end of the period 1,752,416 $ 12.583 $ 26,473 5.119 Year ended Number Weighted Aggregate Weighted Options outstanding at the beginning of the year 4,080,611 $ 9.697 $ 95,855 6.092 Granted 191,200 $ 28.253 Exercised (1,334,351 ) $ 1.521 Forfeited (154,900 ) $ 25.265 Options outstanding at the end of the period 2,782,560 $ 14.026 $ 21,337 6.246 Vested and expected to vest 2,677,503 $ 13.623 $ 21,284 6.156 Options exercisable at the end of the period 1,794,249 $ 8.841 $ 20,496 5.035 There were no 2017. December 31, 2016 2015 $16.870 $28.637, The aggregate intrinsic value in the table above represents the total intrinsic value that would have been received by the option holders had all option holders exercised their options on the last date of the period. Total intrinsic value of options exercised for the years ended December 31, 2017, 2016 2015 $22,382, $9,418 $27,885, December 31, 2017 2016, $2,208 $3,380, 2005 2013 0.887 1.774 The options outstanding as of December 31, 2017 Range of exercise price Options Weighted Weighted Options Weighted Weighted $1.039 - 1.576 401,476 1.383 $ 1.295 401,476 1.383 $ 1.295 $6.230 - 8.800 55,929 3.908 $ 7.125 55,929 3.908 $ 7.125 $12.470 - 16.870 228,001 5.820 $ 13.435 200,917 5.508 $ 12.972 $19.510 - 21.660 374,257 6.606 $ 21.207 284,671 6.567 $ 21.201 $22.010 - 24.230 170,815 6.193 $ 22.292 144,967 6.182 $ 22.342 $29.880 117,829 7.145 $ 29.880 74,758 7.145 $ 29.880 $39.860 107,978 6.225 $ 39.860 99,488 6.225 $ 39.860 1,456,285 4.906 $ 16.172 1,262,206 4.595 $ 15.052 The options outstanding as of December 31, 2016 Range of exercise price Options Weighted Weighted Options Weighted Weighted $0.901 - 1.576 710,562 2.482 $ 1.317 710,562 2.482 $ 1.317 $6.230 - 8.800 89,373 4.963 $ 6.953 89,373 4.963 $ 6.953 $12.470 - 16.870 442,507 7.078 $ 13.812 279,863 6.163 $ 12.470 $19.510 - 21.660 546,959 7.622 $ 21.205 307,302 7.558 $ 21.200 $22.010 - 24.230 295,513 7.299 $ 22.278 191,891 7.289 $ 22.316 $29.880 154,200 8.145 $ 29.880 70,684 8.145 $ 29.880 $39.860 149,234 7.225 $ 39.860 102,741 7.225 $ 39.860 2,388,348 5.861 $ 15.243 1,752,416 5.119 $ 12.583 d. Options issued to consultants: The Company’s outstanding options granted to consultants for services as of December 31, 2017 Issuance date Options for Exercise price Options Exercisable (number) (number) February 2013 1,500 $ 12.470 1,500 February 2023 August 2013 4,188 $ 21.140 4,083 August 2023 March 2014 7,953 $ 39.860 7,163 March 2024 May 2014 6,075 $ 22.010 5,317 May 2024 November 2014 7,107 $ 21.660 4,897 November 2024 May 2015 2,000 $ 19.510 1,292 May 2025 February 2016 2,500 $ 16.870 1,145 February 2026 31,323 25,397 The Company’s outstanding options granted to consultants for services as of December 31, 2016 Issuance date Options for Exercise price Options Exercisable (number) (number) February 2013 1,500 $ 12.470 1,344 February 2023 August 2013 4,188 $ 21.140 3,104 August 2023 October 2013 750 $ 24.230 547 October 2023 March 2014 13,100 $ 39.860 8,187 March 2024 May 2014 6,850 $ 22.010 3,704 May 2024 November 2014 10,246 $ 21.660 4,364 November 2024 May 2015 5,250 $ 19.510 1,750 May 2025 February 2016 2,500 $ 16.870 — February 2026 44,384 23,000 e. Restricted stock units: The following provides a summary of the restricted stock unit activity for the Company for the year ended December 31, 2017: Number of Weighted- Outstanding as of January 1, 2017 1,399,127 $ 19.96 Granted 1,295,653 $ 31.58 Vested (407,458 ) $ 21.89 Forfeited (269,201 ) $ 22.75 Unvested as of December 31, 2017 2,018,121 $ 27.32 The following provides a summary of the restricted stock unit activity for the Company for the year ended December 31, 2016: Number of Weighted- Outstanding as of January 1, 2016 643,506 $ 23.38 Granted 1,038,044 $ 19.67 Vested (199,074 ) $ 22.82 Forfeited (83,349 ) $ 20.21 Unvested as of December 31, 2016 1,399,127 $ 19.96 f. 2015 On May 5, 2015, 2015 March 19, 2015. June 30, 2015. 15% not 85% first 500,000 January 1, 2016, January 1 one 1% December 31 two 2% December 31, 400,000 January 1, 2018, 2017 2016, 188,813, 158,695 21,383 no June 30, 2025; g. Stock-based compensation expense for employees and consultants: The Company recognized non-cash stock-based compensation expense in the consolidated statements of operations as follows (in thousands): Year ended 2017 2016 2015 Cost of revenues $ 1,078 $ 699 $ 419 Research and development 5,209 3,052 1,954 Sales and marketing 8,542 6,104 3,041 General and administrative 5,006 3,083 2,380 Total $ 19,835 $ 12,938 $ 7,794

Note 9 - Income Taxes

Note 9 - Income Taxes	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Income Tax Disclosure [Text Block]	NOTE 9: a. Tax Reform: On December 22, 2017, not · A corporate income tax rate decrease from 35% 21% December 31, 2017 · The transition of U.S international taxation from a worldwide tax system to a territorial system by providing a 100 “100% · A one December 31, 2017; · Taxation of GILTI earned by foreign subsidiaries beginning after December 31, 2017. The Company has not not not 740 No. 118. The Company has calculated its best estimate of the impact of the TCJA for its year end income tax provision in accordance with its understanding of the TCJA and guidance available as of the date of this filing. As a result: Rate Reduction The TCJA reduces the U.S. federal corporate income tax rate from 35% 21% December 31, 2017. The Company estimates that after it utilizes its $23,992 December 31, 2017, not Deemed Repatriation Transition Tax The Deemed Repatriation Transition Tax is a tax on previously untaxed accumulated and current earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, the Company must determine, in addition to other factors, the amount of post- 1986 not 100% Effective for tax years beginning after December 31, 2017, 100% one 10 Prior to enactment of the TCJA, the Company had asserted indefinite reinvestment of the earnings of its foreign subsidiaries. Under the TCJA, however, these earnings are no may not not 2017. first GILTI Tax The TCJA creates a new requirement that certain income ( i.e 1 10 2 Because of the complexity of the new GILTI tax rules, the Company is continuing to evaluate this provision of the TCJA and the application of ASC 740. Whether the Company is expected to have future U.S. inclusions in taxable income related to GILTI depends on not not not 740 not not b. The Company: The Company is taxed in accordance with U.S. tax laws. As of December 31, 2017, $23,992, $10,646 $534, not 2028, 2020 December 31, 2017, $1,412, $24 $195, not 2033, 2032 2026, $344. no may may c. Loss before taxes on income is comprised as follows: Year ended 2017 2016 2015 Domestic $ (18,234 ) $ (16,898 ) $ (20,098 ) Foreign 6,999 319 (499 ) $ (11,235 ) $ (16,579 ) $ (20,597 ) d. Taxes on income (loss) are comprised as follows: Year ended 2017 2016 2015 Current: Domestic: Federal $ (92 ) $ 92 $ — State 191 109 85 Foreign 2,516 930 601 Total current income tax $ 2,615 $ 1,131 $ 686 Deferred: Foreign $ (156 ) $ — $ — Total deferred income tax $ (156 ) $ — $ — Income tax expense $ 2,459 $ 1,131 $ 686 e. Deferred income taxes: 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. The Company’s deferred tax assets are derived from its U.S. net operating loss carry forwards and other temporary differences. In assessing the realization of deferred tax assets, the Company considers whether it is more likely than not not December 31, 2017 2016 Carry forward losses and credits $ 7,407 $ 6,294 Deferred revenues 14,226 16,774 Accrued payroll, commissions, vacation 1,105 2,078 Allowance for doubtful accounts 633 43 Accrued severance pay 239 372 Other 2,668 2,939 Net deferred tax assets before valuation allowance 26,278 28,500 Valuation allowance (26,122 ) (28,500 ) Net deferred tax assets $ 156 $ — Valuation allowance decreased by $2,378 2017, 2016 09, January 1, 2017. 2016 09 $7,849 not $7,849. f. Reconciliation of the theoretical tax expenses: A reconciliation between the theoretical tax expense, assuming all income is taxed at the statutory tax rate applicable to income of the Company, and the actual tax expense (benefit) as reported in the consolidated statements of operations is as follows: Year ended December 31, 2017 2016 2015 Loss before taxes, as reported in the consolidated statements of operations $ (11,235 ) $ (16,579 ) $ (20,597 ) Statutory tax rate 34 % 34 % 34 % Theoretical tax benefits on the above amount at the US statutory tax rate $ (3,820 ) $ (5,637 ) $ (7,003 ) Income tax at rate other than the U.S. statutory tax rate (934 ) 68 333 Tax advances and non-deductible expenses including equity based compensation expenses 3,123 4,298 1,061 Operating losses and other temporary differences for which valuation allowance was provided (10,203 ) 3,001 6,558 Research and Development Tax Credit 1,126 (1,182 ) - State tax (563 ) (536 ) (477 ) Impact of rate change 12,121 (360 ) (82 ) Change in tax reserve for uncertain tax positions 1,576 1,209 320 Other individually immaterial income tax items 33 270 (24 ) Actual tax expense $ 2,459 $ 1,131 $ 686 g. A reconciliation of the beginning and ending amounts of unrecognized tax benefits in the years ended December 31, 2016 2015 Gross unrecognized tax benefits as of January 1, 2016 $ 897 Increase/decrease in tax position for current year 992 Increase/decrease in tax position for prior years 217 Gross unrecognized tax benefits as of December 31, 2016 $ 2,106 Increase/decrease in tax position for current year 1,752 Increase/decrease in tax position for prior years (176 ) Gross unrecognized tax benefits as of December 31, 2017 $ 3,682 There was $3,682 $3,400 $172 December 31, 2017. h. Foreign taxation: 1. 1959 Conditions for entitlement to the benefits: The benefits available to a Beneficiary Enterprise relate only to taxable income attributable to the specific investment program and are conditioned upon terms stipulated in the Investment Law and the related regulations and the criteria set forth in the applicable certificate of approval (for a Beneficiary Enterprise). If VSL does not may The Office of the Chief Scientist at Israel’s Ministry of Industry, Trade and Labor approved the Israeli subsidiary as an R&D-incentive enterprise for a foreign resident company in accordance with the Encouragement of Capital Investments (Consolidated Version) Law. If cash dividends are distributed out of tax exempt profits in a manner other than upon complete liquidation, VSL will then become liable for tax at the rate of 10% 25% 2. As of December 31, 2017, $3,401 no not i. Tax assessments: The Company has not 2013 2016. December 31, 2016, 2012 2009 may In January 2017, 2013 2015. 740. The Company has final tax assessments for VSL in Israel through 2012, 2012 2012. VSG in Germany, VSC in Canada, VIRE in Ireland and VAUS in Australia do not

Note 10 - Financial Expenses, N

Note 10 - Financial Expenses, Net	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Other Nonoperating Income and Expense [Text Block]	NOTE 10: Year ended 2017 2016 2015 Financial income: Interest on bank deposits, net $ 747 $ 520 $ 330 Foreign currency transactions gains, net 1,773 — — Other 27 — — 2,547 520 330 Financial expenses: Bank charges 185 149 95 Foreign currency transactions losses, net — 1,224 1,711 Other — 32 47 (185 ) (1,405 ) (1,853 ) $ 2,362 $ (885 ) $ (1,523 )

Note 11 - Geographic Informatio

Note 11 - Geographic Information and Major Customer and Product Data	12 Months Ended
	Dec. 31, 2017
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	NOTE 11: Summary information about geographic areas: ASC 280, one 1 Year ended 2017 2016 2015 Revenues based on customer’s location: United States $ 134,438 $ 100,281 $ 73,343 EMEA (*) 70,128 52,410 44,994 Rest of the World 12,798 11,765 8,873 Total revenues $ 217,364 $ 164,456 $ 127,210 (*) Sales to customers in France accounted for $22,762, $17,129 $13,570 December 31, 2017, 2016 2015, During the years ended December 31, 2017, 2016 2015, no 10% December 31, 2017 2016 Long-lived assets by geographic region: United States $ 7,072 $ 7,664 Israel 2,944 1,827 France 1,426 207 Other 454 212 $ 11,896 $ 9,910

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Use of Estimates, Policy [Policy Text Block]	a. Use of Estimates: The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates, judgments and assumptions. The Company’s management believes that the estimates, judgments and assumptions used are reasonable based upon information available at the time they are made. These estimates, judgments and assumptions can affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the dates of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. On an ongoing basis, the Company’s management evaluates estimates, including those related to accounts receivable and sales allowances, fair values of stock-based awards, deferred taxes and income tax uncertainties, and contingent liabilities. Such estimates are based on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	b. Financial Statements in U.S. Dollars: Most of the revenues and costs of VSI are denominated in United States dollars (“dollars”). Some of the subsidiaries’ revenues and costs are primarily incurred in Euros, the Pound Sterling, Canadian dollars, Australian dollars and NIS; however, the Company’s management believes that the dollar is the primary currency of the economic environment in which VSI and each of its subsidiaries operate. Thus, the dollar is the Company’s functional and reporting currency. Accordingly, transactions denominated in currencies other than the functional currency are re-measured to the functional currency in accordance with ASC No. 830,
Consolidation, Policy [Policy Text Block]	c. Principles of Consolidation: The consolidated financial statements include the accounts of VSI and its wholly-owned subsidiaries, VSL, VSUK, VSG, VSF, VSC, VIRE and VAUS. All intercompany transactions and balances have been eliminated upon consolidation.
Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block]	d. Cash, Cash Equivalents and Short-Term Investments: The Company accounts for investments in marketable securities in accordance with ASC No. 320, three The Company considers all high quality investments purchased with original maturities at the date of purchase greater than three may one As of December 31, 2017 Amortized Gross Gross Fair Cash and cash equivalents Cash $ 49,819 $ - $ - $ 49,819 Money market funds 6,870 - - 6,870 Total $ 56,689 $ - $ - $ 56,689 Short-term investments US Treasury securities $ 39,758 $ *) $ (27 ) $ 39,731 Term bank deposits 40,137 - - 40,137 Total $ 79,895 $ - $ (27 ) $ 79,868 *) Represents an amount lower than $1. All the US Treasury securities in short-term investments have a stated effective maturity of less than 12 December 31, 2017. As of December 31, 2016 Amortized Gross Gross Fair Cash and cash equivalents Cash $ 42,175 $ - $ - $ 42,175 Money market funds 6,140 - - 6,140 Total $ 48,315 $ - $ - $ 48,315 Short-term investments Term bank deposits $ 65,493 - - $ 65,493 Total $ 65,493 $ - $ - $ 65,493 The gross unrealized loss related to these short-term investments was due primarily to changes in interest rates. The Company reviews its short-term investments on a regular basis to evaluate whether or not not one not December 31, 2017, not A short-term bank deposit is a deposit with a maturity of more than three one 0.60% 1.35% 0.55% 1.11%, December 31, 2017 2016, 0.03% 0.15% December 31, 2017 2016,
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	e. Restricted Cash: Restricted cash is primarily invested in certificates of deposit and is used mostly as security for the Company’s lease commitments. The Company had no December 31, 2017 2016, $547 $488 December 31, 2017 2016,
Property, Plant and Equipment, Policy [Policy Text Block]	f. Property and Equipment: Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets at the following annual rates: % Computer equipment 33 Office furniture and equipment 14 - 15 Leasehold improvements Over the shorter of the expected lease
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	g. Impairment of Long-Lived Assets: The Company’s long-lived assets are reviewed for impairment in accordance with ASC No. 360 may not December 31, 2017, 2016 2015, no
Lessee, Leases [Policy Text Block]	h. Long-Term Lease Deposits: Long-term lease deposits include long-term deposits for offices.
Revenue Recognition, Policy [Policy Text Block]	i. Revenue Recognition: The Company generates revenues in the form of software license fees and related maintenance and services fees. Maintenance and services primarily consist of fees for maintenance services (including support and unspecified upgrades and enhancements when and if they are available) and professional services (including training) that are not The Company accounts for the sale of perpetual software in accordance with ASC No. 985 605, 985 605, 985 605 The Company determines the fair value based on the stand alone sales price charged for maintenance, and professional services. The Company has defined classes of transactions, based on the value of licensed software products purchased from the Company. The Company prices renewals for each class of transaction as a fixed percentage of the total gross value of licensed software products the customer purchased. Software license revenues are recognized when persuasive evidence of an arrangement exists, the software license has been delivered, there are no no not The Company recognizes revenues from the sale of term license arrangements, ratably, on a straight-line basis, over the term of the underlying contract, and is typically up to one The Company recognizes revenues from maintenance ratably over the term of the underlying maintenance contract term. The term of the maintenance contract is usually one Revenues from professional services consist mostly of time and material services and, accordingly, are generally recognized as the services are performed or when the service term has expired. Professional services bundled with licensed software and other software related elements are not Deferred revenues represent mostly unrecognized fees billed or collected for maintenance and professional services. The Company does not one December 31, 2017, 2016 2015, no
Cost of Sales, Policy [Policy Text Block]	j. Cost of Revenues: Cost of revenues consists of the cost of maintenance and services, resulting from costs associated with support, and professional services.
Compensation Related Costs, Policy [Policy Text Block]	k. Accounting for Stock-Based Compensation: The Company accounts for stock-based compensation in accordance with ASC No. 718, No. 718 The Company recognizes compensation expenses for the value of its awards granted based on the straight-line method over the requisite service period of each of the awards. The Company applies ASC 718 505 50, 505 50. The Company selected the Black-Scholes-Merton option pricing model as the most appropriate fair value method for its stock options awards, whereas the fair value of restricted stock units is based on the market value of the underlying shares at the date of grant. The fair value of options granted to employees and non-employee directors is estimated at the date of grant using the following weighted average assumptions: For the year ended December 31, 2017, no December 31, 2016 2015, 0%, 62.1% 65.0%, 1.42% 1.94% 2.00%, 6.25. The Company used its historical volatility in accordance with ASC 718. 110, zero no may not no The non-cash compensation expenses related to employees and consultants for the years ended December 31, 2017, 2016 2015 $19,835, $12,938 $7,794, Effective as of January 1, 2017, 2016 09, 718 2016 09” 2016 09 not 2016 09, $2,616 January 1, 2017. ASU 2016 09 $7,131 $718 December 31, 2016, 2016 09, 2016 09 January 1, 2017. January 1, 2017 no January 1, 2017. Additionally, ASU 2016 09
Research, Development, and Computer Software, Policy [Policy Text Block]	l. Research and Development Costs: Research and development costs are charged to the statement of operations as incurred. ASC No. 985 20, Based on the Company’s product development process, technological feasibility is established upon the completion of a working model. The Company does not
Income Tax, Policy [Policy Text Block]	m. Income Taxes: The Company accounts for income taxes in accordance with ASC No. 740, not ASC 740 two first not second 50%
Derivatives, Policy [Policy Text Block]	n. Derivative Instruments: The Company’s primary objective for holding derivative instruments is to reduce its exposure to foreign currency rate changes. The Company reduces its exposure by entering into forward foreign exchange contracts with respect to operating expenses that are forecast to be incurred in currencies other than the U.S. dollar. A majority of the Company’s revenues and operating expenditures are transacted in U.S. dollars. However, certain operating expenditures are incurred in or exposed to other currencies, primarily the NIS. The Company has established forecasted transaction currency risk management programs to protect against fluctuations in fair value and the volatility of future cash flows caused by changes in exchange rates. The Company’s currency risk management program includes forward foreign exchange contracts designated as cash flow hedges. These forward foreign exchange contracts generally mature within 12 not Derivative instruments measured at fair value and their classification on the consolidated balance sheets are presented in the following table (in thousands): Assets as of Liabilities as of Notional Fair Notional Fair Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships—included in other current assets and accrued expenses and other short term liabilities $ 1,746 $ 163 $ 46,116 $ (479 ) For the years ended December 31, 2017 2016, $2,649 $332, no December 31, 2017 2016.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	o. Concentrations of Credit Risks: Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents, short-term investments and trade receivables. The Company’s cash, cash equivalents and short-term investments are invested in major banks mainly in the United States but also in the United Kingdom, France, Germany, Israel, Canada, Ireland and Australia. Such deposits in the United States may not The Company’s trade receivables are geographically diversified and derived primarily from sales to a network of distributors and VARs mainly in the United States and Europe. Concentration of credit risk with respect to trade receivables is limited by credit limits, ongoing credit evaluation and account monitoring procedures. The Company performs ongoing credit evaluations of its channel partners and establishes an allowance for doubtful accounts based upon a specific review of all significant outstanding invoices. The Company writes off receivables when they are deemed uncollectible and having exhausted all collection efforts.
Retirement And Severance Pay, Policy [Policy Text Block]	p. Retirement and Severance Pay: VSI makes available to its employees a retirement plan (the “U.S. Plan”) that qualifies as a deferred salary arrangement under Section 401 1986, may 100% 3% 50% 3% 5% may 80% Pursuant to Israel’s Severance Pay Law, Israeli employees are entitled to severance pay equal to one 14 1963 14” 8.33% 14 not The Company’s liability for severance pay for the employees of its French subsidiary is calculated pursuant to French law, according to which French employees are entitled to an indemnity (a statutory redundancy). The law provides for the payment of severance payment to any employee working for the French subsidiary for at least a year. VSUK makes available to certain eligible employees a pension plan whereby participants in the plan may 100% 3% Total Company expenses related to retirement and severance pay amounted to $4,801, $3,775 $3,085 December 31, 2017, 2016 2015, December 31, 2017 2016 $1,781 $1,664,
Fair Value of Financial Instruments, Policy [Policy Text Block]	q. Fair Value of Financial Instruments: Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three • Level 1: • Level 2: not • Level 3: The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The carrying amounts of cash and cash equivalents, trade receivables, short-term investments and trade payables approximate their fair value due to the short-term maturity of such instruments.
Earnings Per Share, Policy [Policy Text Block]	r. Basic and Diluted Net Loss Per Share: Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential shares of common stock, including stock options, to the extent dilutive. Basic and diluted net loss per share was the same for each period presented as the inclusion of all potential shares of common stock outstanding would have been anti-dilutive.
Commitments and Contingencies, Policy [Policy Text Block]	s. Contingent Liabilities: The Company accounts for its contingent liabilities in accordance with ASC No. 450 With respect to legal matters, provisions are reviewed and adjusted to reflect the impact of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter. As of December 31, 2017 2016, not
Reclassification, Policy [Policy Text Block]	t. Reclassification: Certain amounts in prior years' financial statements have been reclassified to conform to the current year's presentation.
New Accounting Pronouncements, Policy [Policy Text Block]	u. Recently Issued Accounting Pronouncements: In May 2014, No. 2014 09, and issued subsequent amendments to the initial guidance in March 2016, April 2016, May 2016 December 2016 2016 08, 2016 10, 2016 12 2016 20, not 2014 09 December 15, 2016 may July 9, 2015, one 2014 09. December 15, 2017 January 1, 2018 The most significant impact of the new standard relates to the way the Company accounts for term agreements and commission expense. Specifically, under the current revenue standard, the Company recognizes both the term license and maintenance revenues ratably over the contract period whereas under the new revenue standard it would recognize term license revenues upfront and the associated maintenance revenues over the contract period. The Company has also considered the impact of the guidance in ASC 340 40, 340 40, may not Adoption of the standard will result in a reduction of revenues of $1,974 December 31, 2017 $1,407 December 31, 2016, $9,865 $97, December 31, 2017, January 1, 2016 $5,583. Adoption of the standard related to revenue recognition had no Select recast financial statement information, which reflect the preliminary effect of the adoption of the ASU is below. Year ended As Reported Adjustments Recast for Adoption Total revenues $ 217,364 $ (1,974 ) $ 215,390 Operating loss $ (13,597 ) $ 178 $ (13,419 ) Income taxes $ (2,459 ) $ (328 ) $ (2,787 ) Net loss $ (13,694 ) $ (151 ) $ (13,845 ) Year ended As Reported Adjustments Recast for Adoption Total revenues $ 164,456 $ 1,407 $ 165,863 Operating loss $ (15,694 ) $ 3,699 $ (11,995 ) Income taxes $ (1,131 ) $ (182 ) $ (1,313 ) Net loss $ (17,710 ) $ 3,517 $ (14,193 ) December 31, 2017 Balance Sheet Data As Reported Adjustments Recast for Adoption Assets Current assets: Prepaid expenses and other current assets $ 7,130 $ 9,865 $ 16,995 Liabilities and stockholders’ equity Current liabilities: Accrued expenses and other short term liabilities $ 42,453 $ 1,014 $ 43,006 Deferred revenues $ 73,891 $ (227 ) $ 73,664 Long-term liabilities: Deferred revenues $ 7,034 $ 130 $ 7,164 In January 2016, 2016 13, 2016 13 January 1, 2020, In February 2016, 2016 02, not 12 12 842 840, December 15, 2018, In November 2016, 2016 18, 230 December 15, 2017. December 31, 2017 The adoption of this ASU has an immaterial impact on the Company’s consolidated statements of cash flows. The following table provides a reconciliation of cash and cash equivalents, and long term restricted cash reported within the consolidated balance sheets that sum to the total of such amounts in the consolidated statements of cash flows: December 31. December 31. December 31. Cash and cash equivalents $ 56,689 $ 48,315 $ 49,241 Long term restricted cash included in other assets 547 488 467 Cash, cash equivalents and long term restricted cash shown in the consolidated statement of cash flows $ 57,236 $ 48,803 $ 49,708 In January 2018, No. 118, not not

Note 2 - Significant Accounti20

Note 2 - Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Cash, Cash Equivalents and Investments [Table Text Block]	As of December 31, 2017 Amortized Gross Gross Fair Cash and cash equivalents Cash $ 49,819 $ - $ - $ 49,819 Money market funds 6,870 - - 6,870 Total $ 56,689 $ - $ - $ 56,689 Short-term investments US Treasury securities $ 39,758 $ *) $ (27 ) $ 39,731 Term bank deposits 40,137 - - 40,137 Total $ 79,895 $ - $ (27 ) $ 79,868 As of December 31, 2016 Amortized Gross Gross Fair Cash and cash equivalents Cash $ 42,175 $ - $ - $ 42,175 Money market funds 6,140 - - 6,140 Total $ 48,315 $ - $ - $ 48,315 Short-term investments Term bank deposits $ 65,493 - - $ 65,493 Total $ 65,493 $ - $ - $ 65,493
Property, Plant and Equipment Estimated Useful Life [Table Text Block]	% Computer equipment 33 Office furniture and equipment 14 - 15 Leasehold improvements Over the shorter of the expected lease
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	Assets as of Liabilities as of Notional Fair Notional Fair Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships—included in other current assets and accrued expenses and other short term liabilities $ 1,746 $ 163 $ 46,116 $ (479 )
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	Year ended As Reported Adjustments Recast for Adoption Total revenues $ 217,364 $ (1,974 ) $ 215,390 Operating loss $ (13,597 ) $ 178 $ (13,419 ) Income taxes $ (2,459 ) $ (328 ) $ (2,787 ) Net loss $ (13,694 ) $ (151 ) $ (13,845 ) Year ended As Reported Adjustments Recast for Adoption Total revenues $ 164,456 $ 1,407 $ 165,863 Operating loss $ (15,694 ) $ 3,699 $ (11,995 ) Income taxes $ (1,131 ) $ (182 ) $ (1,313 ) Net loss $ (17,710 ) $ 3,517 $ (14,193 ) December 31, 2017 Balance Sheet Data As Reported Adjustments Recast for Adoption Assets Current assets: Prepaid expenses and other current assets $ 7,130 $ 9,865 $ 16,995 Liabilities and stockholders’ equity Current liabilities: Accrued expenses and other short term liabilities $ 42,453 $ 1,014 $ 43,467 Deferred revenues $ 73,891 $ (227 ) $ 73,664 Long-term liabilities: Deferred revenues $ 7,034 $ 130 $ 7,164
Schedule of Cash and Cash Equivalents [Table Text Block]	December 31. December 31. December 31. Cash and cash equivalents $ 56,689 $ 48,315 $ 49,241 Long term restricted cash included in other assets 547 488 467 Cash, cash equivalents and long term restricted cash shown in the consolidated statement of cash flows $ 57,236 $ 48,803 $ 49,708

Note 3 - Prepaid Expenses and21

Note 3 - Prepaid Expenses and Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block]	December 31, 2017 2016 Prepaid expenses $ 6,044 $ 2,871 Government institutions & other receivables 542 369 Deferred charges - 256 Foreign currency forward contracts derivatives 163 - Short-term deposits 374 122 Other 7 32 $ 7,130 $ 3,650

Note 4 - Property and Equipme22

Note 4 - Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Property, Plant and Equipment [Table Text Block]	December 31, 2017 2016 Cost: Computer equipment $ 8,473 $ 7,800 Office furniture and equipment 2,263 2,094 Leasehold improvements 9,163 7,459 19,899 17,353 Accumulated depreciation 8,003 7,443 Property and equipment, net $ 11,896 $ 9,910

Note 5 - Accrued Expenses and23

Note 5 - Accrued Expenses and Other Short Term Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	December 31, 2017 2016 Employees $ 17,748 $ 12,306 Accrued expenses 9,507 6,777 Government authorities and other 14,006 8,293 Foreign exchange forward contract derivatives - 479 Other short term liabilities 1,192 624 $ 42,453 $ 28,479

Note 6 - Commitments and Cont24

Note 6 - Commitments and Contingent Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Payments Due By 2018 $ 6,418 2019 5,561 2020 4,335 2021 4,561 2022 4,587 Thereafter 21,063 $ 46,525

Note 7 - Fair Value Measureme25

Note 7 - Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	As of December 31, 2017 As of December 31, 2016 Level I Level II Level Fair Level I Level II Level Fair Financial assets: Cash equivalents: Money market funds 6,870 – – 6,870 6,140 – – 6,140 Short-term investments: US Treasury securities 39,731 – – 39,731 – – – – Term bank deposits 40,137 – – 40,137 65,493 – – 65,493 Other current assets: Forward foreign exchange contracts – 163 – 163 – – – – Financial liabilities: Forward foreign exchange contracts – – – – – (479 ) – (479 ) Total financial assets (liabilities) $ 86,738 $ 163 $ – $ 86,901 $ 71,633 $ (479 ) $ – $ 71,154

Note 8 - Stockholders' Equity (

Note 8 - Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Schedule of Stock by Class [Table Text Block]	Authorized Issued and outstanding Number of shares December 31, December 31, 2017 2016 2017 2016 Stock of $0.001 par value: Common stock 200,000,000 200,000,000 28,146,162 26,821,762
Share-based Compensation, Stock Options, Activity [Table Text Block]	Year ended Number Weighted Aggregate Weighted Options outstanding at the beginning of the year 2,388,348 $ 15.243 $ 30,025 5.861 Granted - $ - Exercised (832,270 ) $ 13.031 Forfeited (99,793 ) $ 19.930 Options outstanding at the end of the period 1,456,285 $ 16.172 $ 47,152 4.906 Vested and expected to vest 1,456,285 $ 16.172 $ 47,152 4.906 Options exercisable at the end of the period 1,262,206 $ 15.052 $ 42,282 4.595 Year ended Number Weighted Aggregate Weighted Options outstanding at the beginning of the year 2,782,560 $ 14.026 $ 21,337 6.246 Granted 135,000 $ 16.870 Exercised (445,535 ) $ 5.901 Forfeited (83,677 ) $ 27.126 Options outstanding at the end of the period 2,388,348 $ 15.243 $ 30,025 5.861 Vested and expected to vest 2,331,800 $ 15.074 $ 29,689 5.806 Options exercisable at the end of the period 1,752,416 $ 12.583 $ 26,473 5.119 Year ended Number Weighted Aggregate Weighted Options outstanding at the beginning of the year 4,080,611 $ 9.697 $ 95,855 6.092 Granted 191,200 $ 28.253 Exercised (1,334,351 ) $ 1.521 Forfeited (154,900 ) $ 25.265 Options outstanding at the end of the period 2,782,560 $ 14.026 $ 21,337 6.246 Vested and expected to vest 2,677,503 $ 13.623 $ 21,284 6.156 Options exercisable at the end of the period 1,794,249 $ 8.841 $ 20,496 5.035
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Range of exercise price Options Weighted Weighted Options Weighted Weighted $1.039 - 1.576 401,476 1.383 $ 1.295 401,476 1.383 $ 1.295 $6.230 - 8.800 55,929 3.908 $ 7.125 55,929 3.908 $ 7.125 $12.470 - 16.870 228,001 5.820 $ 13.435 200,917 5.508 $ 12.972 $19.510 - 21.660 374,257 6.606 $ 21.207 284,671 6.567 $ 21.201 $22.010 - 24.230 170,815 6.193 $ 22.292 144,967 6.182 $ 22.342 $29.880 117,829 7.145 $ 29.880 74,758 7.145 $ 29.880 $39.860 107,978 6.225 $ 39.860 99,488 6.225 $ 39.860 1,456,285 4.906 $ 16.172 1,262,206 4.595 $ 15.052 Range of exercise price Options Weighted Weighted Options Weighted Weighted $0.901 - 1.576 710,562 2.482 $ 1.317 710,562 2.482 $ 1.317 $6.230 - 8.800 89,373 4.963 $ 6.953 89,373 4.963 $ 6.953 $12.470 - 16.870 442,507 7.078 $ 13.812 279,863 6.163 $ 12.470 $19.510 - 21.660 546,959 7.622 $ 21.205 307,302 7.558 $ 21.200 $22.010 - 24.230 295,513 7.299 $ 22.278 191,891 7.289 $ 22.316 $29.880 154,200 8.145 $ 29.880 70,684 8.145 $ 29.880 $39.860 149,234 7.225 $ 39.860 102,741 7.225 $ 39.860 2,388,348 5.861 $ 15.243 1,752,416 5.119 $ 12.583
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Issuance date Options for Exercise price Options Exercisable (number) (number) February 2013 1,500 $ 12.470 1,500 February 2023 August 2013 4,188 $ 21.140 4,083 August 2023 March 2014 7,953 $ 39.860 7,163 March 2024 May 2014 6,075 $ 22.010 5,317 May 2024 November 2014 7,107 $ 21.660 4,897 November 2024 May 2015 2,000 $ 19.510 1,292 May 2025 February 2016 2,500 $ 16.870 1,145 February 2026 31,323 25,397 Issuance date Options for Exercise price Options Exercisable (number) (number) February 2013 1,500 $ 12.470 1,344 February 2023 August 2013 4,188 $ 21.140 3,104 August 2023 October 2013 750 $ 24.230 547 October 2023 March 2014 13,100 $ 39.860 8,187 March 2024 May 2014 6,850 $ 22.010 3,704 May 2024 November 2014 10,246 $ 21.660 4,364 November 2024 May 2015 5,250 $ 19.510 1,750 May 2025 February 2016 2,500 $ 16.870 — February 2026 44,384 23,000
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	Number of Weighted- Outstanding as of January 1, 2017 1,399,127 $ 19.96 Granted 1,295,653 $ 31.58 Vested (407,458 ) $ 21.89 Forfeited (269,201 ) $ 22.75 Unvested as of December 31, 2017 2,018,121 $ 27.32 Number of Weighted- Outstanding as of January 1, 2016 643,506 $ 23.38 Granted 1,038,044 $ 19.67 Vested (199,074 ) $ 22.82 Forfeited (83,349 ) $ 20.21 Unvested as of December 31, 2016 1,399,127 $ 19.96
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	Year ended 2017 2016 2015 Cost of revenues $ 1,078 $ 699 $ 419 Research and development 5,209 3,052 1,954 Sales and marketing 8,542 6,104 3,041 General and administrative 5,006 3,083 2,380 Total $ 19,835 $ 12,938 $ 7,794

Note 9 - Income Taxes (Tables)

Note 9 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	Year ended 2017 2016 2015 Domestic $ (18,234 ) $ (16,898 ) $ (20,098 ) Foreign 6,999 319 (499 ) $ (11,235 ) $ (16,579 ) $ (20,597 )
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	Year ended 2017 2016 2015 Current: Domestic: Federal $ (92 ) $ 92 $ — State 191 109 85 Foreign 2,516 930 601 Total current income tax $ 2,615 $ 1,131 $ 686 Deferred: Foreign $ (156 ) $ — $ — Total deferred income tax $ (156 ) $ — $ — Income tax expense $ 2,459 $ 1,131 $ 686
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	December 31, 2017 2016 Carry forward losses and credits $ 7,407 $ 6,294 Deferred revenues 14,226 16,774 Accrued payroll, commissions, vacation 1,105 2,078 Allowance for doubtful accounts 633 43 Accrued severance pay 239 372 Other 2,668 2,939 Net deferred tax assets before valuation allowance 26,278 28,500 Valuation allowance (26,122 ) (28,500 ) Net deferred tax assets $ 156 $ —
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year ended December 31, 2017 2016 2015 Loss before taxes, as reported in the consolidated statements of operations $ (11,235 ) $ (16,579 ) $ (20,597 ) Statutory tax rate 34 % 34 % 34 % Theoretical tax benefits on the above amount at the US statutory tax rate $ (3,820 ) $ (5,637 ) $ (7,003 ) Income tax at rate other than the U.S. statutory tax rate (934 ) 68 333 Tax advances and non-deductible expenses including equity based compensation expenses 3,123 4,298 1,061 Operating losses and other temporary differences for which valuation allowance was provided (10,203 ) 3,001 6,558 Research and Development Tax Credit 1,126 (1,182 ) - State tax (563 ) (536 ) (477 ) Impact of rate change 12,121 (360 ) (82 ) Change in tax reserve for uncertain tax positions 1,576 1,209 320 Other individually immaterial income tax items 33 270 (24 ) Actual tax expense $ 2,459 $ 1,131 $ 686
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	Gross unrecognized tax benefits as of January 1, 2016 $ 897 Increase/decrease in tax position for current year 992 Increase/decrease in tax position for prior years 217 Gross unrecognized tax benefits as of December 31, 2016 $ 2,106 Increase/decrease in tax position for current year 1,752 Increase/decrease in tax position for prior years (176 ) Gross unrecognized tax benefits as of December 31, 2017 $ 3,682

Note 10 - Financial Expenses,28

Note 10 - Financial Expenses, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Schedule Of Nonoperating Income, by Component [Table Text Block]	Year ended 2017 2016 2015 Financial income: Interest on bank deposits, net $ 747 $ 520 $ 330 Foreign currency transactions gains, net 1,773 — — Other 27 — — 2,547 520 330 Financial expenses: Bank charges 185 149 95 Foreign currency transactions losses, net — 1,224 1,711 Other — 32 47 (185 ) (1,405 ) (1,853 ) $ 2,362 $ (885 ) $ (1,523 )

Note 11 - Geographic Informat29

Note 11 - Geographic Information and Major Customer and Product Data (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Tables
Revenue from External Customers by Geographic Areas [Table Text Block]	Year ended 2017 2016 2015 Revenues based on customer’s location: United States $ 134,438 $ 100,281 $ 73,343 EMEA (*) 70,128 52,410 44,994 Rest of the World 12,798 11,765 8,873 Total revenues $ 217,364 $ 164,456 $ 127,210
Long-lived Assets by Geographic Areas [Table Text Block]	December 31, 2017 2016 Long-lived assets by geographic region: United States $ 7,072 $ 7,664 Israel 2,944 1,827 France 1,426 207 Other 454 212 $ 11,896 $ 9,910

Note 1 - General (Details Textu

Note 1 - General (Details Textual)	12 Months Ended
	Dec. 31, 2017
Operations Commenced Date	Jan. 1, 2005
Entity Incorporation, Date of Incorporation	Nov. 24, 2004
Subsidiary or Equity Method Investee, Number	7

Note 2 - Significant Accounti31

Note 2 - Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2017
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities		$ 0
Restricted Cash and Cash Equivalents, Current		0	$ 0
Restricted Cash and Cash Equivalents, Noncurrent		547	488	$ 467
Asset Impairment Charges		$ 0	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		0	135,000	191,200
Fair Value Assumptions, Expected Dividend Rate			0.00%	0.00%
Fair Value Assumptions, Expected Volatility Rate			62.10%	65.00%
Fair Value Assumptions, Risk Free Interest Rate			1.42%
Fair Value Assumptions, Expected Term			6 years 91 days	6 years 91 days
Allocated Share-based Compensation Expense		$ 19,835	$ 12,938	$ 7,794
Minimum Tax Percentage Attained Likely to be Realized upon Ultimate Settlement		50.00%
Severance and Retirement Costs		$ 4,801	3,775	3,085
Revenues		217,364	164,456	127,210
Deferred Tax Assets, Valuation Allowance		26,122	28,500
Other Noncurrent Liabilities [Member]
Restructuring Reserve		$ 1,781	1,664
Foreign Plan [Member] | VSUK Plan [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent		8.33%
UNITED KINGDOM | VSUK Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		100.00%
Defined Contribution Plan, Contributions, Percentage of Participants Base Pay		3.00%
Deferred Salary Arrangement [Member] | UNITED STATES
Defined Contribution Plan, Employer Matching Contribution, Percent of Match		100.00%
Defined Contribution, Plan Employer Matching Contribution, Percent of Participants Contribution		50.00%
Foreign Exchange Contract [Member]
Derivative, Gain (Loss) on Derivative, Net		$ 2,649	332
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net		0	0
Accounting Standards Update 2016-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption
Deferred Tax Assets, Operating Loss Carryforwards, Domestic					$ 7,131
Deferred Tax Assets, Operating Loss Carryforwards, State and Local					718
Deferred Tax Assets, Valuation Allowance					7,849
Accounting Standards Update 2016-09 [Member] | Domestic Tax Authority [Member]
Deferred Tax Assets, Valuation Allowance					7,131
Accounting Standards Update 2016-09 [Member] | State and Local Jurisdiction [Member]
Deferred Tax Assets, Valuation Allowance					$ 718
Accounting Standards Update 2014-09 [Member] | Scenario, Forecast [Member] | As of January 1, 2016 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 5,583
Accounting Standards Update 2014-09 [Member] | Scenario, Forecast [Member] | Restatement Adjustments [Member] | Year Ended December 31, 2017 [Member]
Revenues	(1,974)
Accounting Standards Update 2014-09 [Member] | Scenario, Forecast [Member] | Restatement Adjustments [Member] | Year Ended December 31, 2016 [Member]
Revenues	1,407
Accounting Standards Update 2014-09 [Member] | Scenario, Forecast [Member] | Restatement Adjustments [Member] | As of December 31, 2017 [Member]
Prepaid Expense	9,865
Deferred Revenue	$ (97)
Retained Earnings [Member] | Accounting Standards Update 2016-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption			(2,616)
Employees and Consultants [Member]
Allocated Share-based Compensation Expense		$ 19,835	$ 12,938	$ 7,794
Israel, New Shekels
Investment Interest Rate		0.03%	0.15%
Minimum [Member]
Fair Value Assumptions, Risk Free Interest Rate				1.94%
Minimum [Member] | Deferred Salary Arrangement [Member] | UNITED STATES
Defined Contribution Plan, Contributions, Percentage of Participants Base Pay		3.00%
Minimum [Member] | United States of America, Dollars
Investment Interest Rate		0.60%	0.55%
Maximum [Member]
Fair Value Assumptions, Risk Free Interest Rate				2.00%
Maximum [Member] | Deferred Salary Arrangement [Member] | UNITED STATES
Defined Contribution Plan, Employer Matching Contribution, Percent of Base Pay		3.00%
Defined Contribution Plan, Contributions, Percentage of Participants Base Pay		5.00%
Participant Matching Contribution Percentage of Base Remuneration		80.00%
Maximum [Member] | United States of America, Dollars
Investment Interest Rate		0.135%	0.111%

Note 2 - Significant Accounti32

Note 2 - Significant Accounting Policies - Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Member]
Amortized cost		$ 56,689	$ 48,315
Gross unrealized gains
Gross unrealized losses
Fair value		56,689	48,315
Cash and Cash Equivalents [Member] | Cash [Member]
Amortized cost		49,819	42,175
Gross unrealized gains
Gross unrealized losses
Fair value		49,819	42,175
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Amortized cost		6,870	6,140
Gross unrealized gains
Gross unrealized losses
Fair value		6,870	6,140
Cash and Cash Equivalents [Member] | US Treasury Securities Included in Cash and Cash Equivalents [Member]
Amortized cost		39,758
Gross unrealized gains	[1]
Gross unrealized losses		(27)
Fair value		39,731
Short-term Investments [Member]
Amortized cost		79,895	65,493
Gross unrealized gains
Gross unrealized losses		(27)
Fair value		79,868	65,493
Short-term Investments [Member] | Term Bank Deposits [Member]
Amortized cost		40,137	65,493
Gross unrealized gains
Gross unrealized losses
Fair value		$ 40,137	$ 65,493
[1]	Represents an amount lower than $1.

Note 2 - Significant Accounti33

Note 2 - Significant Accounting Policies - Property and Equipment, Schedule of Depreciation Annual Rates and Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2017
Computer Equipment [Member]
Depreciation rate	33.00%
Office Furniture and Equipment [Member] | Minimum [Member]
Depreciation rate	14.00%
Office Furniture and Equipment [Member] | Maximum [Member]
Depreciation rate	15.00%
Leasehold Improvements [Member]
Leasehold improvements	Over the shorter of the expected lease term or estimated useful life

Note 2 - Significant Accounti34

Note 2 - Significant Accounting Policies - Derivative Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Notional amount	$ 1,746	$ 46,116
Derivative assets, fair value	$ 163
Derivative liabilities, fair value		$ (479)

Note 2 - Significant Accounti35

Note 2 - Significant Accounting Policies - Recast Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total revenues	$ 217,364	$ 164,456	$ 127,210
Operating loss	(13,597)	(15,694)	(19,074)
Income taxes	(2,459)	(1,131)	(686)
Net loss	(13,694)	(17,710)	$ (21,283)
Current assets:
Prepaid expenses and other current assets	7,130	3,650
Current liabilities:
Accrued expenses and other short term liabilities	42,453	28,479
Deferred revenues	73,891	58,478
Long-term liabilities:
Deferred revenues	7,034	3,562
Restatement Adjustment [Member] | Accounting Standards Update 2014-09 [Member]
Total revenues	(1,974)	1,407
Operating loss	178	3,699
Income taxes	(328)	(182)
Net loss	(151)	3,517
Current assets:
Prepaid expenses and other current assets	9,865
Current liabilities:
Accrued expenses and other short term liabilities	1,014
Deferred revenues	(227)
Long-term liabilities:
Deferred revenues	130
Pro Forma [Member] | Accounting Standards Update 2014-09 [Member]
Total revenues	215,390	165,863
Operating loss	(13,419)	(11,995)
Income taxes	(2,787)	(1,313)
Net loss	(13,845)	$ (14,193)
Current assets:
Prepaid expenses and other current assets	16,995
Current liabilities:
Accrued expenses and other short term liabilities	43,467
Deferred revenues	73,664
Long-term liabilities:
Deferred revenues	$ 7,164

Note 2 - Significant Accounti36

Note 2 - Significant Accounting Policies - Cash and Cash Equivalents, and Long Term Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and cash equivalents	$ 56,689	$ 48,315	$ 49,241
Long term restricted cash included in other assets	547	488	467
Cash, cash equivalents and long term restricted cash shown in the consolidated statement of cash flows	$ 57,236	$ 48,803	$ 49,708	$ 76,904

Note 3 - Prepaid Expenses and37

Note 3 - Prepaid Expenses and Other Current Assets - Schedule Of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Prepaid expenses		$ 6,044	$ 2,871
Government institutions & other receivables		542	369
Deferred charges	[1]		256
Foreign currency forward contracts derivatives		163
Short-term deposits		374	122
Other		7	32
Total		$ 7,130	$ 3,650
[1]	Deferred charges relate to lease incentive, see Note 6b.

Note 4 - Property and Equipme38

Note 4 - Property and Equipment, Net (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Depreciation	$ 3,328	$ 2,180	$ 1,615

Note 4 - Property and Equipme39

Note 4 - Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Cost:
Property and equipment, gross	$ 19,899	$ 17,353
Accumulated depreciation	8,003	7,443
Property and equipment, net	11,896	9,910
Computer Equipment [Member]
Cost:
Property and equipment, gross	8,473	7,800
Office Furniture and Equipment [Member]
Cost:
Property and equipment, gross	2,263	2,094
Leasehold Improvements [Member]
Cost:
Property and equipment, gross	$ 9,163	$ 7,459

Note 5 - Accrued Expenses and40

Note 5 - Accrued Expenses and Other Short Term Liabilities - Schedule of Accrued Expenses and Other Short Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Employees	$ 17,748	$ 12,306
Accrued expenses	9,507	6,777
Government authorities and other	14,006	8,293
Foreign exchange forward contract derivatives		479
Other short term liabilities	1,192	624
Total	$ 42,453	$ 28,479

Note 6 - Commitments and Cont41

Note 6 - Commitments and Contingent Liabilities (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Rent Expense		$ 4,075	$ 3,258	$ 4,296
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals		732
Deferred Rent Credit, Current		941	624
Deferred Rent Credit, Noncurrent		$ 4,780	$ 5,377
Promissory Note [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 7,000
Debt Instrument, Basis Spread on Variable Rate	0.15%
Line of Credit Facility, Interest Rate at Period End		4.35%
Long-term Line of Credit		$ 0
Promissory Note [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Effective Percentage		4.10%

Note 6 - Commitments and Cont42

Note 6 - Commitments and Contingent Liabilities - Aggregate Minimum Rental Commitments Under Non-cancelable Leases (Details) $ in Thousands	Dec. 31, 2017USD ($)
2,018	$ 6,418
2,019	5,561
2,020	4,335
2,021	4,561
2,022	4,587
Thereafter	21,063
Total	$ 46,525

Note 7 - Fair Value Measureme43

Note 7 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Total financial assets (liabilities)	$ 71,633
Foreign Exchange Forward [Member]
Derivative assets
Derivative liabilities
Short-term Investments [Member] | Term Bank Deposits [Member]
Short-term investments, at fair value	65,493
Money Market Funds [Member]
Cash equivalents	6,140
US Treasury Securities Included in Cash and Cash Equivalents [Member]
Short-term investments, at fair value
Fair Value, Inputs, Level 1 [Member]
Total financial assets (liabilities)	86,738	$ (479)
Fair Value, Inputs, Level 1 [Member] | Foreign Exchange Forward [Member]
Derivative assets
Derivative liabilities		(479)
Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member] | Term Bank Deposits [Member]
Short-term investments, at fair value	40,137
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Cash equivalents	6,870
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities Included in Cash and Cash Equivalents [Member]
Short-term investments, at fair value	39,731
Fair Value, Inputs, Level 2 [Member]
Total financial assets (liabilities)	163	71,154
Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member]
Derivative assets	163
Derivative liabilities		(479)
Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member] | Term Bank Deposits [Member]
Short-term investments, at fair value		65,493
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Cash equivalents		6,140
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities Included in Cash and Cash Equivalents [Member]
Short-term investments, at fair value
Fair Value, Inputs, Level 3 [Member]
Total financial assets (liabilities)	86,901
Fair Value, Inputs, Level 3 [Member] | Foreign Exchange Forward [Member]
Derivative assets	163
Derivative liabilities
Fair Value, Inputs, Level 3 [Member] | Short-term Investments [Member] | Term Bank Deposits [Member]
Short-term investments, at fair value	40,137
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Cash equivalents	6,870
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities Included in Cash and Cash Equivalents [Member]
Short-term investments, at fair value	$ 39,731

Note 8 - Stockholders' Equity44

Note 8 - Stockholders' Equity (Details Textual) $ / shares in Units, $ in Thousands	Jun. 30, 2015shares	Nov. 14, 2013shares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2013shares	Dec. 31, 2017USD ($)$ / sharesshares	Jan. 01, 2018shares	Jan. 01, 2017shares	Jan. 01, 2016shares
Common Stock, Shares Authorized			200,000,000	200,000,000			200,000,000
Common Stock, Par or Stated Value Per Share | $ / shares			$ 0.001	$ 0.001			$ 0.001
Common Stock, Number of Voting Rights			1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			0	135,000	191,200
Common Stock, Capital Shares Reserved for Future Issuance, Annual Increase, Maximum									1,072,870	1,042,766
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares			$ 0	$ 16.87	$ 28.637
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | $			$ 22,382	$ 9,418	$ 27,885
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $			$ 2,208	$ 3,380			$ 2,208
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			323 days	1 year 282 days
Subsequent Event [Member]
Common Stock, Capital Shares Reserved for Future Issuance, Annual Increase, Maximum								1,125,846
The 2005 Stock Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance						4,713,319
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross							0
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			0				0
The 2013 Omnibus Equity Award Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance		1,904,633
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Reserved for Grant		4.00%
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum		5.00%
The 2013 Omnibus Equity Award Plan [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
2015 ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate	15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	85.00%
Percent of Shares Increase, Employee Stock Purchase Plan	1.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	500,000
Common Stock Availability Threshold, Employee Stock Purchase Plan	2.00%
Shares Increase Threshold, Employee Stock Purchase Plan	400,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized			188,813	158,695	21,383

Note 8 - Stockholders' Equity -

Note 8 - Stockholders' Equity - Composition of Common Stock (Details) - shares	Dec. 31, 2017	Dec. 31, 2016
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	28,146,162	26,821,762

Note 8 - Stockholders' Equity46

Note 8 - Stockholders' Equity - Composition of Common Stock (Details) (Parentheticals) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Common stock, outstanding (in shares)	28,146,162	26,821,762
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001

Note 8 - Stockholders' Equity47

Note 8 - Stockholders' Equity - Stock Options Activities (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Options outstanding at the beginning of the year (in shares)	2,388,348	2,782,560	4,080,611
Options outstanding at the beginning of the year, weighted average exercise price (in dollars per share)	$ 15.243	$ 14.026	$ 9.697
Options outstanding at the beginning of the year, aggregate intrinsic value	$ 47,152	$ 30,025	$ 21,337	$ 95,855
Options outstanding at the beginning of the year, weighted average remaining contractual life (Year)	4 years 330 days	5 years 314 days	6 years 89 days	6 years 33 days
Granted (in shares)	0	135,000	191,200
Granted, weighted average exercise price (in dollars per share)		$ 16.87	$ 28.253
Exercised (in shares)	(832,270)	(445,535)	(1,334,351)
Exercised, weighted average exercise price (in dollars per share)	$ 13.031	$ 5.901	$ 1.521
Forfeited (in shares)	(99,793)	(83,677)	(154,900)
Forfeited, weighted average exercise price (in dollars per share)	$ 19.93	$ 27.126	$ 25.265
Options outstanding at the end of the period, weighted average exercise price (in dollars per share)	$ 16.172	$ 15.243	$ 14.026	$ 9.697
Vested and expected to vest (in shares)	1,456,285	2,331,800	2,677,503
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 16.172	$ 15.074	$ 13.623
Vested and expected to vest, aggregate intrinsic value	$ 47,152	$ 29,689	$ 21,284
Vested and expected to vest, weighted average remaining contractual life (Year)	4 years 330 days	5 years 294 days	6 years 56 days
Options exercisable at the end of the year (in shares)	1,262,206	1,752,416	1,794,249
Options exercisable at the end of the year, weighted average exercise price (in dollars per share)	$ 15.052	$ 12.583	$ 8.841
Options exercisable at the end of the year, aggregate intrinsic value	$ 42,282	$ 26,473	$ 20,496
Options exercisable at the end of the year, weighted average remaining contractual life (Year)	4 years 217 days	5 years 43 days	5 years 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	135,000	191,200
Options outstanding at the end of the period (in shares)	1,456,285	2,388,348	2,782,560	4,080,611
Vested and expected to vest (in shares)	1,456,285	2,331,800	2,677,503
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 16.172	$ 15.074	$ 13.623

Note 8 - Stockholders' Equity48

Note 8 - Stockholders' Equity - Options Outstanding Separated Into Range of Exercise Price (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Upper range of exercise price (in dollars per share)
Options outstanding (in shares)	1,456,285	2,388,348
Weighted average remaining contractual life (Year)	4 years 330 days	5 years 314 days
Weighted average exercise price (in dollars per share)	$ 16.172	$ 15.243
Options exercisable (in shares)	1,262,206	1,752,416
Weighted average remaining contractual life, exercisable (Year)	4 years 217 days	5 years 43 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 15.052	$ 12.583
Range One [Member]
Upper range of exercise price (in dollars per share)	1.576	1.576
Lower range of exercise price (in dollars per share)	$ 1.039	$ 0.901
Options outstanding (in shares)	401,476	710,562
Weighted average remaining contractual life (Year)	1 year 139 days	2 years 175 days
Weighted average exercise price (in dollars per share)	$ 1.295	$ 1.317
Options exercisable (in shares)	401,476	710,562
Weighted average remaining contractual life, exercisable (Year)	1 year 139 days	2 years 175 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 1.295	$ 1.317
Range Two [Member]
Upper range of exercise price (in dollars per share)	8.80	8.80
Lower range of exercise price (in dollars per share)	$ 6.23	$ 6.23
Options outstanding (in shares)	55,929	89,373
Weighted average remaining contractual life (Year)	3 years 331 days	4 years 351 days
Weighted average exercise price (in dollars per share)	$ 7.125	$ 6.953
Options exercisable (in shares)	55,929	89,373
Weighted average remaining contractual life, exercisable (Year)	3 years 331 days	4 years 351 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 7.125	$ 6.953
Range Three [Member]
Upper range of exercise price (in dollars per share)	16.87	16.87
Lower range of exercise price (in dollars per share)	$ 12.47	$ 12.47
Options outstanding (in shares)	228,001	442,507
Weighted average remaining contractual life (Year)	5 years 299 days	7 years 28 days
Weighted average exercise price (in dollars per share)	$ 13.435	$ 13.812
Options exercisable (in shares)	200,917	279,863
Weighted average remaining contractual life, exercisable (Year)	5 years 185 days	6 years 59 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 12.972	$ 12.47
Range Four [Member]
Upper range of exercise price (in dollars per share)	21.66	21.66
Lower range of exercise price (in dollars per share)	$ 19.51	$ 19.51
Options outstanding (in shares)	374,257	546,959
Weighted average remaining contractual life (Year)	6 years 221 days	7 years 227 days
Weighted average exercise price (in dollars per share)	$ 21.207	$ 21.205
Options exercisable (in shares)	284,671	307,302
Weighted average remaining contractual life, exercisable (Year)	6 years 206 days	7 years 203 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 21.201	$ 21.20
Range Five [Member]
Upper range of exercise price (in dollars per share)	24.23	24.23
Lower range of exercise price (in dollars per share)	$ 22.01	$ 19.51
Options outstanding (in shares)	170,815	295,513
Weighted average remaining contractual life (Year)	6 years 70 days	7 years 109 days
Weighted average exercise price (in dollars per share)	$ 22.292	$ 22.278
Options exercisable (in shares)	144,967	191,891
Weighted average remaining contractual life, exercisable (Year)	6 years 66 days	7 years 105 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 22.342	$ 22.316
Range Six [Member]
Upper range of exercise price (in dollars per share)
Lower range of exercise price (in dollars per share)		$ 22.01
Options outstanding (in shares)	117,829	154,200
Weighted average remaining contractual life (Year)	7 years 52 days	8 years 52 days
Weighted average exercise price (in dollars per share)	$ 29.88	$ 29.88
Options exercisable (in shares)	74,758	70,684
Weighted average remaining contractual life, exercisable (Year)	7 years 52 days	8 years 52 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 29.88	$ 29.88
Range Seven [Member]
Upper range of exercise price (in dollars per share)
Options outstanding (in shares)	107,978	149,234
Weighted average remaining contractual life (Year)	6 years 82 days	7 years 82 days
Weighted average exercise price (in dollars per share)	$ 39.86	$ 39.86
Options exercisable (in shares)	99,488	102,741
Weighted average remaining contractual life, exercisable (Year)	6 years 82 days	7 years 82 days
Weighted average exercise price of options exercisable (in dollars per share)	$ 39.86	$ 39.86

Note 8 - Stockholders' Equity49

Note 8 - Stockholders' Equity - Outstanding Options Granted to Consultants for Sales and Pre-marketing Services (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Granted, weighted average exercise price (in dollars per share)		$ 16.87	$ 28.253
Options exercisable at the end of the year (in shares)	1,262,206	1,752,416	1,794,249
Consultants [Member]
Options for shares of common stock (in shares)	31,323	44,384
Granted, weighted average exercise price (in dollars per share)
Options exercisable at the end of the year (in shares)	25,397	23,000
Exercisable through
February 2013 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	1,500	1,500
Granted, weighted average exercise price (in dollars per share)	$ 12.47	$ 12.47
Options exercisable at the end of the year (in shares)	1,500	1,344
Exercisable through	February2023	February 2,023
August 2013 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	4,188	4,188
Granted, weighted average exercise price (in dollars per share)	$ 21.14	$ 21.14
Options exercisable at the end of the year (in shares)	4,083	3,104
Exercisable through	August2023	August 2,023
March 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	7,953	13,100
Granted, weighted average exercise price (in dollars per share)	$ 39.86	$ 39.86
Options exercisable at the end of the year (in shares)	7,163	8,187
Exercisable through	March2024	March 2,024
October 2013 [Member] | Consultants [Member]
Options for shares of common stock (in shares)		750
Granted, weighted average exercise price (in dollars per share)		$ 24.23
Options exercisable at the end of the year (in shares)		547
Exercisable through		October 2,023
May 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	6,075	6,850
Granted, weighted average exercise price (in dollars per share)	$ 22.01	$ 22.01
Options exercisable at the end of the year (in shares)	5,317	3,704
Exercisable through	May2024	May 2,024
November 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	7,107	10,246
Granted, weighted average exercise price (in dollars per share)	$ 21.66	$ 21.66
Options exercisable at the end of the year (in shares)	4,897	4,364
Exercisable through	November2024	November2024
May 2015 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	2,000	5,250
Granted, weighted average exercise price (in dollars per share)	$ 19.51	$ 19.51
Options exercisable at the end of the year (in shares)	1,292	1,750
Exercisable through	May2025	May2025
February 2016 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	2,500	2,500
Granted, weighted average exercise price (in dollars per share)	$ 16.87	$ 16.87
Options exercisable at the end of the year (in shares)	1,145
Exercisable through	February2026	February2026

Note 8 - Stockholders' Equity50

Note 8 - Stockholders' Equity - Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Balance, restricted stock units (in shares)	1,399,127	643,506
Balance, weighted average grant date fair value on restricted stock units (in dollars per share)	$ 19.96	$ 23.38
Granted, restricted stock units (in shares)	1,295,653	1,038,044
Granted, weighted average grant date fair value on restricted stock units (in dollars per share)	$ 31.58	$ 19.67
Vested, restricted stock units (in shares)	(407,458)	(199,074)
Vested, weighted average grant date fair value on restricted stock units (in dollars per share)	$ 21.89	$ 22.82
Forfeited, restricted stock units (in shares)	(269,201)	(83,349)
Forfeited, weighted average grant date fair value on restricted stock units (in dollars per share)	$ 22.75	$ 20.21
Balance, restricted stock units (in shares)	2,018,121	1,399,127
Balance, weighted average grant date fair value on restricted stock units (in dollars per share)	$ 27.32	$ 19.96

Note 8 - Stockholders' Equity51

Note 8 - Stockholders' Equity - Non-cash Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock-based compensation	$ 19,835	$ 12,938	$ 7,794
Cost of Sales [Member]
Stock-based compensation	1,078	699	419
Research and Development Expense [Member]
Stock-based compensation	5,209	3,052	1,954
Selling and Marketing Expense [Member]
Stock-based compensation	8,542	6,104	3,041
General and Administrative Expense [Member]
Stock-based compensation	$ 5,006	$ 3,083	$ 2,380

Note 9 - Income Taxes (Details

Note 9 - Income Taxes (Details Textual) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			35.00%	34.00%	34.00%
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount			$ (2,378)
Deferred Tax Assets, Valuation Allowance			26,122	$ 28,500
Unrecognized Tax Benefits			3,682	$ 2,106	$ 897
Unrecognized Tax Benefits that Would Impact Effective Tax Rate			3,400
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense			172
Undistributed Earnings of Foreign Subsidiaries			3,401
Accounting Standards Update 2016-09 [Member]
Deferred Tax Assets, Valuation Allowance						$ 7,849
Israel Tax Authority [Member]
Tax Credit Carryforward, Amount			$ 344
Israel Tax Authority [Member] | VSL [Member] | Earliest Tax Year [Member]
Income Tax Examination, Year under Examination	2,013
Israel Tax Authority [Member] | VSL [Member] | Latest Tax Year [Member]
Income Tax Examination, Year under Examination	2,015
Open Tax Year			2,012
Her Majesty's Revenue and Customs (HMRC) [Member] | VSL [Member] | Latest Tax Year [Member]
Open Tax Year			2,012
Ministry of the Economy, Finance and Industry, France [Member] | VSL [Member] | Latest Tax Year [Member]
Open Tax Year			2,012
Domestic Tax Authority [Member]
Operating Loss Carryforwards			$ 23,992
Domestic Tax Authority [Member] | Earliest Tax Year [Member]
Open Tax Year			2,012
Domestic Tax Authority [Member] | Accounting Standards Update 2016-09 [Member]
Deferred Tax Assets, Valuation Allowance						7,131
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount			$ 1,412
Domestic Tax Authority [Member] | Retention [Member]
Tax Credit Carryforward, Amount			24
Domestic Tax Authority [Member] | Foreign Tax Credit [Member]
Tax Credit Carryforward, Amount			195
State and Local Jurisdiction [Member]
Operating Loss Carryforwards			$ 10,646
State and Local Jurisdiction [Member] | Earliest Tax Year [Member]
Income Tax Examination, Year under Examination			2,013
Open Tax Year			2,009
State and Local Jurisdiction [Member] | Latest Tax Year [Member]
Income Tax Examination, Year under Examination			2,016
State and Local Jurisdiction [Member] | Accounting Standards Update 2016-09 [Member]
Deferred Tax Assets, Valuation Allowance						$ 718
Foreign Tax Authority [Member]
Operating Loss Carryforwards			$ 534
Foreign Tax Authority [Member] | Israel Tax Authority [Member] | VSL [Member] | Minimum [Member]
Tax Rate for Amount of Dividends Distributed, Other Than Complete Liquidation			10.00%
Foreign Tax Authority [Member] | Israel Tax Authority [Member] | VSL [Member] | Maximum [Member]
Tax Rate for Amount of Dividends Distributed, Other Than Complete Liquidation			25.00%
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%

Note 9 - Income Taxes - Schedul

Note 9 - Income Taxes - Schedule of Profit (Loss) Before Taxes on Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Domestic	$ (18,234)	$ (16,898)	$ (20,098)
Foreign	6,999	319	(499)
Loss before income taxes	$ (11,235)	$ (16,579)	$ (20,597)

Note 9 - Income Taxes - Sched54

Note 9 - Income Taxes - Schedule of Income Taxes on Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (92)	$ 92
State	191	109	85
Foreign	2,516	930	601
Total current income tax	2,615	1,131	686
Deferred:
Foreign	(156)
Total deferred income tax	(156)
Income tax expense	$ 2,459	$ 1,131	$ 686

Note 9 - Income Taxes - Sched55

Note 9 - Income Taxes - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Carry forward losses and credits	$ 7,407	$ 6,294
Deferred revenues	14,226	16,774
Accrued payroll, commissions, vacation	1,105	2,078
Allowance for doubtful accounts	633	43
Accrued severance pay	239	372
Other	2,668	2,939
Net deferred tax assets before valuation allowance	26,278	28,500
Valuation allowance	(26,122)	(28,500)
Net deferred tax assets	$ 156

Note 9 - Income Taxes - Sched56

Note 9 - Income Taxes - Schedule of Reconciliation of Theoretical Tax Expense and Actual Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss before taxes, as reported in the consolidated statements of operations	$ (11,235)	$ (16,579)	$ (20,597)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%	34.00%	34.00%
Theoretical tax benefits on the above amount at the US statutory tax rate	$ (3,820)	$ (5,637)	$ (7,003)
Income tax at rate other than the U.S. statutory tax rate	(934)	68	333
Tax advances and non-deductible expenses including equity based compensation expenses	3,123	4,298	1,061
Operating losses and other temporary differences for which valuation allowance was provided	(10,203)	3,001	6,558
Research and Development Tax Credit	1,126	(1,182)
State tax	(563)	(536)	(477)
Impact of rate change	12,121	(360)	(82)
Change in tax reserve for uncertain tax positions	(1,576)	(1,209)	(320)
Other individually immaterial income tax items	33	270	(24)
Income tax expense	$ 2,459	$ 1,131	$ 686

Note 9 - Income Taxes - Reconci

Note 9 - Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Gross unrecognized tax benefits	$ 2,106	$ 897
Increase/decrease in tax position for current year	1,752	992
Increase/decrease in tax position for prior years		217
Increase/decrease in tax position for prior years	(176)
Gross unrecognized tax benefits	$ 3,682	$ 2,106

Note 10 - Financial Expenses,58

Note 10 - Financial Expenses, Net - Summary of Financial Income and Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest on bank deposits, net	$ 747	$ 520	$ 330
Foreign currency transactions gains, net	1,773
Other	27
Financial Income	2,547	520	330
Bank charges	185	149	95
Foreign currency transactions losses, net		1,224	1,711
Other		32	47
Financial expenses	(185)	(1,405)	(1,853)
Total	$ 2,362	$ (885)	$ (1,523)

Note 11 - Geographic Informat59

Note 11 - Geographic Information and Major Customer and Product Data (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Number of Reportable Segments	1
Revenues	$ 217,364	$ 164,456	$ 127,210
FRANCE
Revenues	$ 22,762	$ 17,129	$ 13,570

Note 11 - Geographic Informat60

Note 11 - Geographic Information and Major Customer and Product Data - Revenues Within Geographical Areas (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total revenues		$ 217,364	$ 164,456	$ 127,210
UNITED STATES
Total revenues		134,438	100,281	73,343
EMEA [Member]
Total revenues	[1]	70,128	52,410	44,994
Rest of World [Member]
Total revenues		$ 12,798	$ 11,765	$ 8,873
[1]	Sales to customers in France accounted for $22,762, $17,129 and $13,570 for the years ended December 31, 2017, 2016 and 2015, respectively.

Note 11 - Geographic Informat61

Note 11 - Geographic Information and Major Customer and Product Data - Long-lived Assets by Geographic Region (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long-lived assets	$ 11,896	$ 9,910
UNITED STATES
Long-lived assets	7,072	7,664
ISRAEL
Long-lived assets	2,944	1,827
FRANCE
Long-lived assets	1,426	207
Other [Member]
Long-lived assets	$ 454	$ 212