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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2018	Jul. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	QUALYS, INC.
Entity Central Index Key	0001107843
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		38,997,535

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 86,779	$ 86,591
Short-term marketable securities	235,740	201,823
Accounts receivable, net of allowance of $748 and $816 as of June 30, 2018 and December 31, 2017, respectively	52,535	64,412
Prepaid expenses and other current assets	15,815	16,524
Total current assets	390,869	369,350
Long-term marketable securities	64,215	67,224
Property and equipment, net	64,973	58,557
Deferred tax assets, net	23,570	25,066
Intangible assets, net	14,605	12,401
Long-term investment	2,500	0
Goodwill	1,849	1,549
Restricted cash	1,200	1,200
Other noncurrent assets	7,134	2,178
Total assets	570,915	537,525
Current liabilities:
Accounts payable	1,024	1,144
Accrued liabilities	27,454	21,444
Deferred revenues, current	151,419	143,186
Total current liabilities	179,897	165,774
Deferred revenues, noncurrent	13,327	17,136
Other noncurrent liabilities	12,452	11,071
Total liabilities	205,676	193,981
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value; 20,000,000 shares authorized, no shares issued and outstanding at June 30, 2018 and December 31, 2017	0	0
Common stock, $0.001 par value; 1,000,000,000 shares authorized; 38,985,798 and 38,598,117 shares issued and outstanding at June 30, 2018 and December 31, 2017	39	39
Additional paid-in capital	320,226	304,155
Accumulated other comprehensive loss	(821)	(574)
Retained earnings	45,795	39,924
Total stockholders’ equity	365,239	343,544
Total liabilities and stockholders’ equity	$ 570,915	$ 537,525

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ (748)	$ (816)
Preferred stock, par or stated value per share (USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par or stated value per share (USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	38,985,798	38,598,117
Common stock, shares outstanding	38,985,798	38,598,117

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Revenues	$ 68,153	$ 55,302	$ 133,031	$ 108,423
Cost of revenues	16,248	12,153	32,149	24,447
Gross profit	51,905	43,149	100,882	83,976
Operating expenses:
Research and development	13,128	10,525	25,681	20,348
Sales and marketing	18,976	15,383	35,209	31,397
General and administrative	8,906	8,232	20,691	15,566
Total operating expenses	41,010	34,140	81,581	67,311
Income from operations	10,895	9,009	19,301	16,665
Other income (expense), net:
Interest expense	(39)	(1)	(77)	(3)
Interest income	1,452	541	2,542	1,022
Other expense, net	(529)	(180)	(336)	(206)
Total other income, net	884	360	2,129	813
Income before income taxes	11,779	9,369	21,430	17,478
Provision for (benefit from) income taxes	1,486	2,167	1,995	(11,654)
Net income	$ 10,293	$ 7,202	$ 19,435	$ 29,132
Net income per share:
Basic (USD per share)	$ 0.26	$ 0.19	$ 0.50	$ 0.79
Diluted (USD per share)	$ 0.24	$ 0.18	$ 0.46	$ 0.74
Weighted average shares used in computing net income per share:
Basic (shares)	38,987	37,277	38,843	36,887
Diluted (shares)	42,215	39,535	42,074	39,207

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 10,293	$ 7,202	$ 19,435	$ 29,132
Available-for-sale marketable securities:
Change in net unrealized gain (loss), net of tax	65	(29)	(342)	(80)
Reclassification adjustment for net realized gain included in net income, net of tax	79	20	95	2
Other comprehensive income (loss), net of tax	144	(9)	(247)	(78)
Comprehensive income	$ 10,437	$ 7,193	$ 19,188	$ 29,054

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 19,435	$ 29,132
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	14,249	9,783
Bad debt expense	0	296
Loss on disposal of property and equipment	9	2
Stock-based compensation	15,914	10,779
Amortization of premiums and accretion of discounts on marketable securities	(169)	850
Deferred income taxes	681	(20,897)
Excess tax benefits from stock-based compensation	0	8,368
Changes in operating assets and liabilities:
Accounts receivable	11,876	369
Prepaid expenses and other assets	(4,073)	(1,067)
Accounts payable	(331)	(206)
Accrued liabilities	6,238	109
Deferred revenues	4,424	10,947
Other non-current liabilities	(1,026)	477
Net cash provided by operating activities	67,227	48,942
Cash flows from investing activities:
Purchases of marketable securities	(151,825)	(102,665)
Sales and maturities of marketable securities	120,838	111,288
Purchases of property and equipment	(13,240)	(13,179)
Business acquisition	3,359	0
Purchase of privately-held investment	(2,500)	0
Net cash used in investing activities	(50,086)	(4,556)
Cash flows from financing activities:
Proceeds from exercise of stock options	12,174	14,603
Payments for taxes related to net share settlement of equity awards	(8,935)	(15,154)
Principal payments under capital lease obligations	(794)	0
Repurchase of common stock	(19,356)	0
Net cash used in financing activities	(16,911)	(551)
Effect of Exchange Rate on Cash and Cash Equivalents, Continuing Operations	(42)	0
Net increase in cash, cash equivalents and restricted cash	188	43,835
Cash, cash equivalents and restricted cash at beginning of period	87,791	87,937
Cash, cash equivalents and restricted cash at end of period	87,979	131,772
Supplemental disclosures of cash flow information:
Cash paid for interest expense	81	0
Cash paid for income taxes, net of refunds	1,201	540
Purchases of property and equipment recorded in accounts payable and accrued liabilities	4,481	1,193
Purchase of assets under capital lease	2,708	0
Not yet received tenant allowance recorded in other assets, accrued liabilities and other non-current liabilities	$ 0	$ 8,076

The Company and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
The Company and Summary of Significant Accounting Policies	The Company and Summary of Significant Accounting Policies Description of Business Qualys, Inc. (the “Company”, "we", "us", "our") was incorporated in the state of Delaware on December 30, 1999. The Company is headquartered in Foster City, California and has majority-owned subsidiaries throughout the world. The Company is a pioneer and leading provider of cloud-based security and compliance solutions that enable organizations to identify security risks to their IT infrastructures, help protect their IT systems and applications from ever-evolving cyber-attacks and achieve compliance with internal policies and external regulations. The Company’s cloud solutions address the growing security and compliance complexities and risks that are amplified by the dissolving boundaries between internal and external IT infrastructures and web environments, the rapid adoption of cloud computing and the proliferation of geographically dispersed IT assets. Organizations can use the Company’s integrated suite of solutions delivered on its Qualys cloud platform to cost-effectively obtain a unified view of their security and compliance posture across globally-distributed IT infrastructures. Basis of Presentation The accompanying unaudited condensed consolidated financial statements and condensed footnotes have been prepared by the Company in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") for interim financial information as well as the instructions to Form 10-Q and the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"). Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2017, included herein, was derived from the audited financial statements as of that date but does not include all disclosures, including notes required by U.S. GAAP. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the financial position, results of operations and cash flows for the interim periods. The results of operations for the three and six month periods ended June 30, 2018 are not necessarily indicative of the results of operations expected for the entire year ending December 31, 2018 or for any other future annual or interim period. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, filed with the SEC on February 23, 2018. Use of Estimates The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the condensed consolidated financial statements and the reported results of operations during the reporting period. The Company’s management regularly assesses these estimates, which primarily affect revenue recognition, the valuation of accounts receivable, goodwill and intangible assets, stock-based compensation and the provision for income taxes. Actual results could differ from those estimates and such differences may be material to the accompanying unaudited condensed consolidated financial statements. Cost Method Investments In the second quarter of fiscal 2018, the Company invested $2.5 million in a privately-held company. The Company used the cost method of accounting to account for the investment because it does not hold a controlling interest in this entity and the Company does not have the ability to exercise significant influence over the entity's operating and financial policies. The investment is included in long term assets on the accompanying condensed consolidated balance sheets. The Company's cost method investment is assessed for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company has not recorded any dividends or other-than-temporary impairment charges related to its cost method investment. The fair value of the investment is not readily available, and there are no quoted market prices for the investment. Recently Adopted Accounting Pronouncements Except for the changes below, the Company has consistently applied the accounting policies, described in its Annual Report on Form 10-K for the year ended December 31, 2017, to all periods presented in the condensed consolidated financial statements. The Company adopted Accounting Standards Codification ("ASC") 606 Revenue from Contracts with Customers with a date of initial application of January 1, 2018. The Company adopted ASC 606 using the modified retrospective method and recognized the cumulative effect as an adjustment to the opening balance of equity at January 1, 2018. Therefore, the comparative information from the prior period has not been adjusted and continues to be reported under ASC 605. The impact of adopting ASC 606 was related to the deferral of sales commission costs for new business and when customers increase their renewal orders (“upsells”). The Company previously expensed sales commissions as incurred. Under ASC 606, sales commissions cost related to new business and upsells are recorded as an asset. The Company expenses the commission cost as a selling expense on a straight-line basis over a period of five years. Five years represents the estimated life of the customer relationship taking into account factors such as peer estimates of technology lives and customer lives as well as the Company's own historical data. Applying the practical expedient in ASC 340-40-25-4, the Company expenses commissions related to contract renewals with a renewal contract term of one year or less. The current and noncurrent portions of deferred commissions are included in prepaid expenses and other current assets, and other noncurrent assets, respectively, in its condensed consolidated balance sheets. On January 1, 2018, the Company recorded an increase to retained earnings of $2.7 million which was the net cumulative impact associated with the capitalization of sales commissions. Additionally, the Company recorded a corresponding commission asset balance of $3.5 million and a related deferred tax liability of $0.8 million. There was no impact to the Company's revenues as a result of adopting ASC 606. Without the adoption of ASC 606, commission expenses would have been $0.5 million higher for the three months ended June 30, 2018. See Note 4, “Revenue from Contracts with Customers”, for additional information regarding the impact on the Company's condensed consolidated financial statements. In January 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, which impacts certain aspects of recognition, measurement, presentation and disclosure of financial instruments. The ASU impacts the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. The Company adopted this ASU in its first quarter of 2018. The adoption of this ASU did not have a material impact on the Company's condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force), to provide guidance on the presentation of certain cash receipts and cash payments in the statement of cash flows in order to reduce diversity in existing practice. The Company adopted this ASU in its first quarter of 2018. The adoption of this ASU did not have a material impact on the Company's condensed consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The update provides guidance on the presentation of restricted cash or restricted cash equivalents in the statement of cash flows. The Company adopted this ASU retrospectively in its first quarter of 2018. The Company reclassified restricted cash of $1.2 million for each of the six months ended June 30, 2018 and 2017, in the condensed consolidated statements of cash flows. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which revises the definition of a business and provides new guidance in evaluating when a set of transferred assets and activities is a business. The Company adopted this ASU prospectively in its first quarter of 2018. The adoption of this ASU did not have a material impact on the Company's condensed consolidated financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize all leases, including operating leases, on the balance sheet as a lease asset or lease liability, unless the lease is a short-term lease. ASU 2016-02 also requires additional disclosures regarding leasing arrangements. ASU 2016-02 is effective for the Company beginning in the first quarter of fiscal 2019 and early adoption is permitted. Pursuant to the leasing criteria, most of the Company's leased space and equipment leases will be required to be accounted for as capitalized assets on the balance sheet with offsetting financing obligations. In the statement of operations, what was formerly rent expense will be bifurcated into depreciation and interest expense. The Company is currently evaluating the impact and expects the ASU will have a material impact on its condensed consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment (Topic 350). This standard eliminates Step 2 from the goodwill impairment test, instead requiring an entity to recognize a goodwill impairment charge for the amount by which the goodwill carrying amount exceeds the reporting unit’s fair value. This ASU is effective for interim and annual goodwill impairment tests in fiscal years beginning after December 15, 2019 with early adoption permitted. This ASU must be applied on a prospective basis. The adoption of this ASU is not expected to have a material impact on the Company's condensed consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This ASU eliminates the stranded tax effects in other comprehensive income resulting from the Tax Cuts and Jobs Act (the "2017 Tax Act”). Because the amendments only relate to the reclassification of the income tax effects of the 2017 Tax Act, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. ASU 2018-02 is effective for the Company beginning in the first quarter of fiscal 2019 and early adoption is permitted. The Company is currently evaluating the impact of this ASU on its condensed consolidated financial statements. In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. This ASU expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-07 is effective for the Company beginning in the first quarter of fiscal 2019 and early adoption is permitted. The Company is currently evaluating the impact of this ASU on its condensed consolidated financial statements.

Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. For certain of the Company’s financial instruments, including certain cash equivalents, accounts receivable, accounts payable, and other current liabilities, the carrying amounts approximate their fair values due to the relatively short maturity of these balances.

The Company measures and reports certain cash equivalents, marketable securities and derivative foreign currency forward contracts at fair value in accordance with the provisions of the authoritative accounting guidance that addresses fair value measurements. This guidance establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. The hierarchy is broken down into three levels based on the reliability of inputs as follows:

Level 1—Valuations based on quoted prices in active markets for identical assets or liabilities.

Level 2—Valuations based on other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3—Valuations based on inputs that are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability.

The Company's financial instruments consist of assets and liabilities measured using Level 1 and 2 inputs. Level 1 assets include a highly liquid money market fund, which is valued using unadjusted quoted prices that are available in an active market for an identical asset. Level 2 assets include fixed-income U.S. government agency securities, commercial paper, corporate bonds, asset-backed securities and derivative financial instruments consisting of foreign currency forward contracts. The securities, bonds and commercial paper are valued using prices from independent pricing services based on quoted prices in active markets for similar instruments or on industry models using data inputs such as interest rates and prices that can be directly observed or corroborated in active markets. The foreign currency forward contracts are valued using observable inputs, such as quotations on forward foreign exchange points and foreign interest rates.

The Company's cash and cash equivalents, and marketable securities consist of the following:



	June 30, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	74,427	$	—	$	—		$	74,427
Money market funds	421		—		—			421
Commercial paper	11,931		—		—			11,931
Total	86,779		—		—			86,779
Short-term marketable securities:
Commercial paper	16,816		2		(1		)	16,817
Corporate bonds	37,917		1		(127		)	37,791
U.S. government agencies	181,338		—		(206		)	181,132
Total	236,071		3		(334		)	235,740
Long-term marketable securities:
Asset-backed securities	13,960		—		(38		)	13,922
U.S. government agencies	18,795		7		(71		)	18,731
Corporate bonds	31,902		3		(343		)	31,562
Total	64,657		10		(452		)	64,215
Total	$	387,507	$	13	$	(786	)	$	386,734



	December 31, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	86,500	$	—	$	—		$	86,500
Money market funds	91		—		—			91
Total	86,591		—		—			86,591
Short-term marketable securities:
Commercial paper	12,623		—		(3		)	12,620
Corporate bonds	38,425		1		(64		)	38,362
U.S. government agencies	151,058		—		(217		)	150,841
Total	202,106		1		(284		)	201,823
Long-term marketable securities:
Asset-backed securities	4,998		—		(12		)	4,986
U.S. government agencies	24,269		—		(54		)	24,215
Corporate bonds	38,198		—		(175		)	38,023
Total	67,465		—		(241		)	67,224
Total	$	356,162	$	1	$	(525	)	$	355,638

The following table shows the changes to accumulated other comprehensive loss for the six months ended June 30, 2018 (in thousands):



	Unrealized (Loss) Gain, net
Balance at December 31, 2017	$	(574	)
Change in net unrealized loss on available-for-sale marketable securities, net of tax	(342		)
Amounts reclassified for net realized gain included in net income, net of tax	95
Other comprehensive loss, net of tax	(247		)
Balance at June 30, 2018	$	(821	)

The following table sets forth by level within the fair value hierarchy the fair value of the Company's available-for-sale marketable securities measured on a recurring basis, excluding cash and money market funds:



	June 30, 2018
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	28,749	$	—	$	28,749
U.S. government agencies	—		199,862		—		199,862
Corporate bonds	—		69,353		—		69,353
Asset-backed securities	—		13,922		—		13,922
Total	$	—	$	311,886	$	—	$	311,886



	December 31, 2017
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	12,620	$	—	$	12,620
U.S. government agencies	—		175,056		—		175,056
Corporate bonds	—		76,385		—		76,385
Asset-backed securities	—		4,986		—		4,986
Total	$	—	$	269,047	$	—	$	269,047

There were no transfers between Level 1, Level 2 or Level 3 of the fair value hierarchy, as determined at the end of each reporting period.

The following summarizes the fair value of marketable securities classified as available-for-sale by contractual, or effective, maturity:



	June 30, 2018
	Mature within One Year		Mature after One Year through Two Years		Mature over Two Years		Fair Value
	(in thousands)
Commercial paper	$	28,749	$	—	$	—	$	28,749
U.S. government agencies	181,132		18,730		—		199,862
Corporate bonds	37,791		31,268		294		69,353
Asset-backed securities	13,439		483		—		13,922
Total	$	261,111	$	50,481	$	294	$	311,886

Derivative Financial Instruments

Derivative financial instruments are utilized by the Company to reduce foreign currency exchange risks. The Company uses foreign currency forward contracts to mitigate the impact of foreign currency fluctuations of certain non-U.S. dollar denominated asset positions, primarily cash and accounts receivable. These contracts are recorded within prepaid expenses and other current assets or accrued liabilities in the condensed consolidated balance sheets. Gains and losses resulting from currency exchange rate movements on these forward contracts are recognized in other income (expense) in the accompanying condensed consolidated statements of operations in the period in which the exchange rates change and offset the foreign currency gains and losses on the underlying exposure being hedged. The Company does not enter into derivative financial instruments for trading or speculative purposes.

At June 30, 2018, the Company had two outstanding forward contracts with notional amounts of 10.6 million Euros and 4.8 million British Pounds, respectively, which expired on July 31, 2018. At December 31, 2017, the Company had two outstanding forward contracts with notional amounts of 7.0 million Euros and 4.8 million British Pounds, respectively, which expired on January 31, 2018. These forward contracts were entered into at the end of each month, and thus the fair value of these contracts was $0 at June 30, 2018 and December 31, 2017. These derivatives did not meet the criteria to be designated as hedges. These instruments were valued using Level 2 inputs.

The following summarizes the gains (losses) recognized in Other income (expense), net on the condensed consolidated statement of operations, from forward contracts and other foreign currency transactions:



	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2018			2017			2018			2017
	(in thousands)
Net gain (loss) from forward contracts	$	931		$	(865	)	$	353		$	(1,122	)
Other foreign currency transactions (loss) gain	(1,398		)	733			(588		)	993
Total foreign exchange loss, net	$	(467	)	$	(132	)	$	(235	)	$	(129	)

- Definition

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

+ References + Details

Property and Equipment, Net

6 Months Ended

Jun. 30, 2018

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

Property and equipment, net, which includes assets under capital lease, consists of the following:



	June 30,			December 31,
	2018			2017
	(in thousands)
Computer equipment	$	85,527		$	77,883
Computer software	25,964			20,447
Furniture, fixtures and equipment	5,458			5,075
Assets under capital lease	3,503			—
Scanner appliances	15,234			14,325
Leasehold improvements	16,348			16,067
Total property and equipment	152,034			133,797
Less: accumulated depreciation and amortization	(87,061		)	(75,240		)
Property and equipment, net	$	64,973		$	58,557

Physical scanner appliances and other computer equipment that are or will be subject to leases by customers have a net carrying value of $7.6 million and $6.8 million at June 30, 2018 and December 31, 2017, respectively, including assets that have not been placed in service of $1.1 million and $0.9 million, respectively. Depreciation and amortization expense relating to property and equipment, including capitalized leases, was $6.4 million and $4.9 million for the three months ended June 30, 2018 and 2017, respectively, and $12.8 million and $9.6 million for the six months ended June 30, 2018 and 2017, respectively. Accumulated depreciation under capital leases was $0.5 million at June 30, 2018.

Revenue from Contracts with Customers

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Revenue from Contracts with Customers

In May 2014, the FASB issued a new standard related to revenue recognition. Under the standard, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

On January 1, 2018, the Company adopted ASC 606 using the modified retrospective method applied to those contracts which were not completed as of that date. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported under the accounting standards in effect for the prior period. The Company implemented internal controls and key system functionality to enable the preparation of financial information on adoption. The impact of the standard on the Company's financial statements relates to the Company's accounting for sales commissions. The Company previously expensed sales commissions as incurred. Under ASC 606, the Company is required to capitalize certain contract acquisition costs consisting primarily of commissions paid related to new business and upsells. Applying the practical expedient in ASC 340-40-25-4, the Company expenses commissions related to contract renewals with a renewal contract term of one year or less.

As a result of the adoption, the Company recorded an increase to retained earnings of $2.7 million as of January 1, 2018 which was the net cumulative impact associated with the capitalization of sales commissions. Additionally, the Company recorded a corresponding commission asset balance of $3.5 million and a related deferred tax liability of $0.8 million as of January 1, 2018. There was no impact to the Company's revenues as a result of adopting ASC 606.

Incremental direct costs of obtaining a contract, which consist of sales commissions primarily for new business and upsells, are deferred and amortized over the estimated life of the customer relationship if renewals are expected and the renewal commission is not commensurate with the initial commission. The Company expenses the commission cost as a selling expense on a straight-line basis over a period of five years. The Company classifies deferred commissions as current or noncurrent based on the timing of when it expects to recognize the expense. The current and noncurrent portions of deferred commissions are included in prepaid expenses and other current assets and other noncurrent assets, respectively, in its condensed consolidated balance sheets. The Company has elected the practical expedient for sales commissions related to renewals and expenses these as and when incurred because the amortization period would have been one year or less.

Commission asset balances are as follows (in thousands):



	June 30, 2018		January 1, 2018
Commission asset, current	$	1,004	$	704
Commission asset, noncurrent	$	3,503	$	2,819

For the three and six months ended June 30, 2018, the Company recognized $0.3 million and $0.5 million, respectively, of commission expense from amortization of its commission assets. During the same periods, there was no impairment loss related to capitalized costs. No contract costs were capitalized in the three and six months ended June 30, 2017.

Contract liabilities (deferred revenue) balances are as follows (in thousands):



	June 30, 2018
	ASC 606		Operating Leases		Total
Deferred revenue, current	$	138,142	$	13,277	$	151,419
Deferred revenue, noncurrent	11,894		1,433		13,327
Total	$	150,036	$	14,710	$	164,746

	January 1, 2018
	ASC 606		Operating Leases		Total
Deferred revenue, current	$	130,579	$	12,607	$	143,186
Deferred revenue, noncurrent	15,419		1,717		17,136
Total	$	145,998	$	14,324	$	160,322

The Company records deferred revenue when cash payments are received or due in advance of its performance. The increase in the Company's deferred revenue balances for the six months ended June 30, 2018 is primarily driven by cash payments received or due in advance of satisfying the Company's performance obligations, offset by $98.4 million of revenue recognized in the six months ended June 30, 2018, which was included in the deferred revenue balance as of December 31, 2017.

The Company's performance obligations are typically satisfied ratably over the subscription term as its cloud-based offerings are delivered to customers electronically and over time. In addition, the Company recognizes revenues for certain limited scan arrangements on an as-used basis. The Company recognizes revenue related to the professional services as they are performed.

The Company allocates the transaction price to all separate performance obligations, including transactions that are comprised of lease revenue, in proportion to the standalone selling prices ("SSP") of the goods or services underlying each of those performance obligations at contract inception. If a SSP is not directly observable, the Company determines the SSP using information that may include market conditions and other observable inputs. The Company typically has more than one SSP for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, the Company may use information such as the size of the customer and volume purchased in determining the SSP. The Company's transaction prices are typically a fixed amount for a specific period of time, and the majority of contracts are twelve months with certain customers signing longer term deals. In general, the Company does not offer rights of return, performance bonuses, customer loyalty programs, payments via non-cash methods, refunds, volume rebates, incentive payments, penalties, price concessions or payments or discounts contingent on future events. Consideration is fixed at the time of the contract, and governed by the price list to which that particular customer is subject. The Company’s customer and partner-specific pricing is negotiated and agreed upon via individual customer contracts. In some of its contracts, the Company incorporates tiered pricing based on the number of IP addresses the customer can scan. As customers are required to purchase larger quantities to qualify for the lower-priced tiers, the Company does not grant its customers any material rights. When customers increase their purchased quantities, the Company accounts for the additional purchased quantities and related price change prospectively as the pricing does not impact subscription services previously provided. Physical equipment (scanners and private cloud platforms) are accounted for as operating leases and revenue is recognized over the subscription term.

Accounts receivable, net, consists of the following (in thousands):



	June 30, 2018			January 1, 2018
ASC 606 receivables	$	49,839		$	60,984
Operating lease receivables	3,444			4,244
Less: allowance for doubtful accounts	(748		)	(816		)
Total accounts receivable, net	$	52,535		$	64,412

The Company's payment terms vary by the type and location of its customer and the products or services offered. The term between invoicing and when payment is due is not significant. For certain products or services and customer types, the Company requires payment before the products or services are delivered to the customer.

The following table sets forth the expected revenue from all remaining performance obligations as of June 30, 2018 (in thousands):



	ASC 606 Revenues		Operating Lease Revenues		Total Revenues
2018 (remaining six months)	$	4,548	$	158	$	4,706
2019	13,608		1,060		14,668
2020	9,260		526		9,786
2021	3,260		111		3,371
2022	1,974		20		1,994
2023 and thereafter	1,370		4		1,374
Total	$	34,020	$	1,879	$	35,899

Revenue allocated to remaining performance obligations represents contracted revenue that has not yet been recognized, which includes unearned revenue and amounts that will be invoiced and recognized as revenue in future periods. Remaining performance obligations represents the transaction price of firm orders for which service has not been performed and excludes unexercised renewals.

From time to time, the Company enters into contracts with customers that extend beyond one year, with certain of its customers electing to pay for more than one year of services upon contract execution. For any discounts associated with these multiple year contracts, the Company does not consider these contracts to contain a financing component as its customers typically initiate the longer terms, and the Company's reasoning for entering into the longer terms is not based on financing.

Business Combination Business Combination	6 Months Ended
Business Combination Business Combination	Jun. 30, 2018
Business Combinations [Abstract]
Business Combination	Business Combination On April 1, 2018, the Company acquired the assets of 1Mobility Private Limited ("1Mobility"), a Singapore-based company. The acquisition will allow the Company to provide enterprises of all sizes with the ability to create and continuously update an inventory of mobile devices on all versions of Android, iOS and Windows Mobile in their environment; and to continuously assess their security and compliance posture, while quarantining devices that are compromised or out-of-compliance. Total purchase consideration was $4.0 million, including $0.6 million of deferred consideration due eighteen months from the closing date of the acquisition, subject to potential adjustment from possible indemnity claims. Pro forma financial information for this acquisition has not been presented because it is not material to the Company's condensed consolidated financial statements. The Company accounted for this transaction as a business combination and allocated $3.7 million of the purchase price to technology-based intangible assets and $0.3 million to goodwill. The acquired intangible assets relating to 1Mobility's developed technology are being amortized over the estimated useful lives of approximately four years. Goodwill arising from the 1Mobility acquisition is deductible for tax purposes over 15 years.

Goodwill and Intangible Assets, Net

6 Months Ended

Jun. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets, Net

will and Intangible Assets, Net

Intangible assets consist primarily of developed technology and patent licenses acquired in business combinations. Acquired intangibles are amortized on a straight-line basis over the respective estimated useful lives of the assets.

The carrying values of intangible assets are as follows (in thousands, except for years):



					June 30, 2018
	Weighted Average Life (Years)	Weighted Average Remaining Life (Years)	Cost		Accumulated Amortization			Net Book Value
Developed technology	5	4.1	$	15,856	$	(1,907	)	$	13,949
Patent licenses	14	6.1	1,388		(772		)	616
Total intangibles subject to amortization			$	17,244	$	(2,679	)	14,565
Intangible assets not subject to amortization								40
Total intangible assets, net								$	14,605

					December 31, 2017
	Weighted Average Life (Years)	Weighted Average Remaining Life (Years)	Cost		Accumulated Amortization			Net Book Value
Developed technology	5	4.8	$	14,067	$	(2,371	)	$	11,696
Patent Licenses	14	6.7	1,388		(723		)	665
Total intangibles subject to amortization			$	15,455	$	(3,094	)	12,361
Intangible assets not subject to amortization								40
Total intangible assets, net								$	12,401

Intangible asset amortization expense was $0.9 million and $0.1 million for the three months ended June 30, 2018 and 2017, respectively, and $1.5 million and $0.2 million for the six months ended June 30, 2018 and 2017, respectively.

As of June 30, 2018, the Company expects amortization expense in future periods to be as follows (in thousands):



2018 (remaining six months)	$	1,729
2019	3,456
2020	3,456
2021	3,456
2022	2,302
2023 and thereafter	166
Total expected future amortization expense	$	14,565

Goodwill, which is not subject to amortization, totaled $1.8 million and $1.5 million as of June 30, 2018 and December 31, 2017, respectively.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Commitments and Contingencies

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Leases

The Company leases certain computer equipment and its corporate office and data center facilities under non-cancelable operating leases for varying periods through 2028. In January 2018, the Company entered into a $3.5 million financing arrangement for data center storage equipment, accounted for as a capital lease, with an implied interest rate of 5%.

The following are the minimum annual lease payments due under these leases at June 30, 2018 (in thousands):



	Operating Leases		Capital Leases
	(in thousands)
2018 (remaining six months)	$	4,997	$	885
2019	6,098		1,770
2020	5,747		130
2021	5,030		54
2022	4,547		—
2023 and thereafter	23,609		—
Total minimum lease payments	$	50,028	2,839
Less: amount representing interest			(131		)
Present value of minimum payments			2,708
Less: current portion			(1,667		)
Capital lease obligations, noncurrent			$	1,041

Rent expense was $2.4 million and $2.4 million for the three months ended June 30, 2018 and 2017, respectively, and $4.6 million and $4.3 million for the six months ended June 30, 2018 and 2017, respectively. Although certain of the operating lease agreements provide for rent free periods or escalating rent payments over the terms of the leases, rent expense under these agreements is recognized on a straight-line basis over the term of the lease, starting when the Company takes possession of the property from the landlord. As of June 30, 2018 and December 31, 2017, the Company had accrued $11.1 million and $9.5 million, respectively, of deferred rent related to these agreements, which is reflected in accrued liabilities and other non-current liabilities in the accompanying condensed consolidated balance sheets.

On October 14, 2016, the Company entered into a lease agreement for its new headquarters office facility. The lease payments commenced on May 1, 2018 and the lease has a ten-year term through April 30, 2028. The total commitment of $38.6 million is payable monthly with escalating rental payments throughout the lease term. In connection with this lease, the Company has provided the landlord with a $1.2 million standby letter of credit to secure the Company’s obligations through the end of the lease term, which was classified as restricted cash in the accompanying condensed consolidated balance sheets.

Indemnifications

The Company from time to time enters into certain types of contracts that contingently require it to indemnify various parties against claims from third parties. These contracts primarily relate to (i) the Company's by-laws, under which it must indemnify directors and executive officers, and may indemnify other officers and employees, for liabilities arising out of their relationship, (ii) contracts under which the Company must indemnify directors and certain officers for liabilities arising out of their relationship, and (iii) contracts under which the Company may be required to indemnify customers or resellers from certain liabilities arising from potential infringement of intellectual property rights, as well as potential damages caused by limited product defects. To date, the Company has not incurred and has not recorded any liability in connection with such indemnifications.

The Company maintains director and officer insurance, which may cover certain liabilities arising from its obligation to indemnify its directors.

Contingencies

The Company regularly licenses technology from various third party licensors. From time to time, the Company is audited by its licensors for compliance with the terms of the license agreements. During the quarter ended March 31, 2018, the Company commenced discussions with one of its vendors with respect to compliance with the terms of the applicable license agreement. During the three months ended June 30, 2018, the audit was completed and the Company reached a resolution with its licensor. Management sufficiently accrued for licensing agreement matters in the first quarter of 2018.

Stock-based Compensation

6 Months Ended

Jun. 30, 2018

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

Stock-based Compensation

Equity Incentive Plans

2012 Equity Incentive Plan

Under the 2012 Equity Incentive Plan (the "2012 Plan"), the Company is authorized to grant to eligible participants incentive stock options (“ISOs”), non-statutory stock options (“NSOs”), stock appreciation rights ("SARs"), restricted stock awards ("RSAs"), restricted stock units ("RSUs"), performance units and performance shares equivalent to up to 11,791,139 shares of common stock. Options may be granted with an exercise price that is at least equal to the fair market value of the Company's stock at the date of grant and are exercisable when vested. As of June 30, 2018, 4,211,131 shares were available for grant under the 2012 Plan.

2000 Equity Incentive Plan

Under the 2000 Equity Incentive Plan (the "2000 Plan"), the Company was authorized to grant to eligible participants either ISOs or NSOs. The 2000 Plan was terminated in connection with the closing of the Company's initial public offering, and accordingly, no shares are currently available for grant under the 2000 Plan. The 2000 Plan continues to govern outstanding awards granted thereunder.

Stock-based Compensation

The following table shows a summary of the stock-based compensation expense included in the condensed consolidated statements of operations for the three and six months ended June 30, 2018 and 2017:



	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
	(in thousands)
Cost of revenues	$	609	$	536	$	1,263	$	1,037
Research and development	1,976		1,505		3,817		2,726
Sales and marketing	1,105		1,129		2,506		2,213
General and administrative	3,333		3,277		8,328		4,803
Total stock-based compensation	$	7,023	$	6,447	$	15,914	$	10,779

As of June 30, 2018, the Company had $14.0 million of total unrecognized stock-based compensation cost related to unvested options that it expects to recognize over a weighted-average period of 2.2 years, and $42.1 million of unrecognized stock-based compensation cost related to unvested awards that it expects to recognize over a weighted-average period of 2.9 years. Compensation cost is recognized on a straight-line basis over the service period. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

Stock Option Plan Activity

A summary of the Company’s stock option activity is as follows:



	Outstanding Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
						(in thousands)
Balance as of December 31, 2017	4,495,891		$	25.29	6.6	$	153,129
Granted	154,025		$	71.26
Exercised	(430,848	)	$	28.25
Canceled	(164,766	)	$	38.38
Balance as of June 30, 2018	4,054,302		$	26.19	6.3	$	235,597
Vested and expected to vest - June 30, 2018	3,863,453		$	25.32	6.2	$	227,859
Exercisable - June 30, 2018	2,921,338		$	22.06	5.5	$	181,818

Restricted Stock

A summary of the Company’s RSU and RSA activity is as follows:



	Outstanding RSUs and RSAs		Weighted Average Grant Date Fair Value Per Share

Balance as of December 31, 2017	1,410,588		$	40.34
Granted	188,752		$	71.11
Vested	(342,569	)	$	38.74
Canceled	(121,470	)	$	40.55
Balance as of June 30, 2018	1,135,301		$	45.92
Outstanding and expected to vest - June 30, 2018	980,802		$	45.32

Net Income Per Share

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Net Income Per Share

The computations for basic and diluted net income per share are as follows:



	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
	(in thousands, except per share data)
Numerator:
Net income	$	10,293	$	7,202	$	19,435	$	29,132
Denominator:
Weighted-average shares used in computing net income per share:
Basic	38,987		37,277		38,843		36,887
Effect of potentially dilutive securities:
Common stock options	2,610		2,003		2,576		2,110
Restricted stock units	618		255		655		210
Diluted	42,215		39,535		42,074		39,207
Net income per share:
Basic	$	0.26	$	0.19	$	0.50	$	0.79
Diluted	$	0.24	$	0.18	$	0.46	$	0.74

Potentially dilutive securities not included in the calculation of diluted net income per share because doing so would be antidilutive are as follows:



	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2018	2017	2018	2017
	(in thousands)
Common stock options	125	1,261	81	1,307
Restricted stock units	2	9	30	6
	127	1,270	111	1,313

Stockholder's Equity	6 Months Ended
Stockholder's Equity	Jun. 30, 2018
Equity [Abstract]
Stockholder's Equity	Stockholder's Equity Share Repurchase Program On February 5, 2018, the Company's Board of Directors authorized a $100.0 million share repurchase program, which was announced on February 12, 2018. The stock repurchase authorization does not have an expiration date. The Company's stock repurchases may be effected from time to time through open market purchases. Repurchased shares are retired and reclassified as authorized and unissued shares of common stock. On retirement of the repurchased shares, common stock is reduced by an amount equal to the number of shares being retired multiplied by the par value. The excess of the cost of treasury stock that is retired over its par value is first allocated as a reduction to additional paid-in capital based on the initial public offering price of the stock, with the remaining excess to retained earnings. During the six months ended June 30, 2018, the Company repurchased 256,827 shares of its common stock for approximately $19.4 million. All share repurchases were made using cash resources. As of June 30, 2018, approximately $80.6 million remained available for share repurchases pursuant to the Company's share repurchase program.

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's provision for income taxes for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items, if any, that arise during the period. Each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual effective tax rate changes, the Company makes a cumulative adjustment in such period. The Company's quarterly tax provision, and estimate of its annual effective tax rate, is subject to variation due to several factors, including variability in pre-tax income (or loss), the mix of jurisdictions to which such income relates, changes in how the Company does business, and tax law developments. The Company's estimated effective tax rate for the year differs from the U.S. statutory rate of 21% primarily due to non-deductible stock-based compensation expense, state taxes, foreign income subject to different tax rates than the U.S., and the benefit of U.S. federal income tax credits. The Company recorded an income tax provision of $1.5 million and $2.2 million for the three months ended June 30, 2018 and 2017, respectively, resulting in an effective tax rate of 12.6% and 23.1%, respectively. The tax provision for the three months ended June 30, 2018 compared to the three months ended June 30, 2017 decreased primarily due to the benefit of the lower U.S. federal tax rate that became effective in 2018 as well as the tax benefit of excess stock-based compensation deductions. The Company recorded an income tax provision of $2.0 million and income tax benefit of $11.7 million for the six months ended June 30, 2018 and 2017, respectively, resulting in an effective tax rate of 9.3% and (66.7)%, respectively. The tax provision for the six months ended June 30, 2018 compared to the six months ended June 30, 2017 increased as a result of a reduction in the amount of excess stock-based compensation deductions. On December 22, 2017, the 2017 Tax Act was enacted into law. The new legislation contains significant tax provisions that affect the Company, including a one-time repatriation tax on accumulated foreign earnings, a reduction of the corporate income tax rate from 35% to 21%, which was effective January 1, 2018, and a change from a worldwide tax system to a modified territorial system. In accordance with Staff Accounting Bulletin No. 118 ("SAB 118"), the effects of the 2017 Tax Act may be adjusted within a one-year measurement period from the enactment date of the 2017 Tax Act for items that were previously reported as provisional estimates, or where a provisional estimate could not be made. The income tax provision for the six months ended June 30, 2018, does not reflect any adjustment to the provisional estimates recorded in the year ended December 31, 2017. The Company will continue to assess forthcoming guidance and accounting interpretations on the effects of the 2017 Tax Act and expects to complete its analysis within the measurement period in accordance with the SEC guidance. Such analysis includes both the implications of the newly introduced provisions for Global Intangible Low Tax Income and the detailed analysis of historical foreign earnings and potential correlative adjustments to verify the one-time transition tax does not apply. As of June 30, 2018, the Company had unrecognized tax benefits of $5.6 million, of which $3.1 million, if recognized, would favorably impact the Company's effective tax rate. As of December 31, 2017, the Company had unrecognized tax benefits of $5.1 million, of which $2.8 million, if recognized, would favorably impact the Company's effective tax rate. The Company does not anticipate a material change in its unrecognized tax benefits in the next 12 months.

Segment Information and Information about Geographic Area

6 Months Ended

Jun. 30, 2018

Segment Reporting [Abstract]

Segment Information and Information about Geographic Area

he Company operates in one segment. The Company determines its reportable operating segments in accordance with the provisions in the FASB guidance on segment reporting, which establishes standards for, and requires disclosure of, certain financial information related to reportable operating segments and geographic regions. The Company’s chief operating decision maker is the Chairman, President and Chief Executive Officer, who makes operating decisions, assesses performance and allocates resources on a consolidated basis. All of the Company’s principal operations and decision-making functions are located in the United States.

Revenues by geographic area, based on the location of the customer, are as follows (in thousands):



	Three Months Ended June 30, 2018						Six Months Ended June 30, 2018
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
United States	$	41,675	$	4,124	$	45,799	$	81,983	$	8,130	$	90,113
Foreign	20,551		1,803		22,354		39,446		3,472		42,918
Total	$	62,226	$	5,927	$	68,153	$	121,429	$	11,602	$	133,031

	Three Months Ended June 30, 2017						Six Months Ended June 30, 2017
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
United States	$	35,268	$	3,770	$	39,038	$	69,150	$	7,349	$	76,499
Foreign	14,716		1,548		16,264		28,713		3,211		31,924
Total	$	49,984	$	5,318	$	55,302	$	97,863	$	10,560	$	108,423

Property and equipment, net, by geographic area, are as follows:



	June 30,		December 31,
	2018		2017
	(in thousands)
United States	$	55,596	$	50,785
Foreign	9,377		7,772
Total property and equipment, net	$	64,973	$	58,557

The Company and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Description Of Business	Description of Business Qualys, Inc. (the “Company”, "we", "us", "our") was incorporated in the state of Delaware on December 30, 1999. The Company is headquartered in Foster City, California and has majority-owned subsidiaries throughout the world. The Company is a pioneer and leading provider of cloud-based security and compliance solutions that enable organizations to identify security risks to their IT infrastructures, help protect their IT systems and applications from ever-evolving cyber-attacks and achieve compliance with internal policies and external regulations. The Company’s cloud solutions address the growing security and compliance complexities and risks that are amplified by the dissolving boundaries between internal and external IT infrastructures and web environments, the rapid adoption of cloud computing and the proliferation of geographically dispersed IT assets. Organizations can use the Company’s integrated suite of solutions delivered on its Qualys cloud platform to cost-effectively obtain a unified view of their security and compliance posture across globally-distributed IT infrastructures.
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements and condensed footnotes have been prepared by the Company in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") for interim financial information as well as the instructions to Form 10-Q and the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"). Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2017, included herein, was derived from the audited financial statements as of that date but does not include all disclosures, including notes required by U.S. GAAP. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the financial position, results of operations and cash flows for the interim periods. The results of operations for the three and six month periods ended June 30, 2018 are not necessarily indicative of the results of operations expected for the entire year ending December 31, 2018 or for any other future annual or interim period. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, filed with the SEC on February 23, 2018. Use of Estimates The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the condensed consolidated financial statements and the reported results of operations during the reporting period. The Company’s management regularly assesses these estimates, which primarily affect revenue recognition, the valuation of accounts receivable, goodwill and intangible assets, stock-based compensation and the provision for income taxes. Actual results could differ from those estimates and such differences may be material to the accompanying unaudited condensed consolidated financial statements. Cost Method Investments In the second quarter of fiscal 2018, the Company invested $2.5 million in a privately-held company. The Company used the cost method of accounting to account for the investment because it does not hold a controlling interest in this entity and the Company does not have the ability to exercise significant influence over the entity's operating and financial policies. The investment is included in long term assets on the accompanying condensed consolidated balance sheets. The Company's cost method investment is assessed for impairment when events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company has not recorded any dividends or other-than-temporary impairment charges related to its cost method investment. The fair value of the investment is not readily available, and there are no quoted market prices for the investment. Recently Adopted Accounting Pronouncements Except for the changes below, the Company has consistently applied the accounting policies, described in its Annual Report on Form 10-K for the year ended December 31, 2017, to all periods presented in the condensed consolidated financial statements. The Company adopted Accounting Standards Codification ("ASC") 606 Revenue from Contracts with Customers with a date of initial application of January 1, 2018. The Company adopted ASC 606 using the modified retrospective method and recognized the cumulative effect as an adjustment to the opening balance of equity at January 1, 2018. Therefore, the comparative information from the prior period has not been adjusted and continues to be reported under ASC 605. The impact of adopting ASC 606 was related to the deferral of sales commission costs for new business and when customers increase their renewal orders (“upsells”). The Company previously expensed sales commissions as incurred. Under ASC 606, sales commissions cost related to new business and upsells are recorded as an asset. The Company expenses the commission cost as a selling expense on a straight-line basis over a period of five years. Five years represents the estimated life of the customer relationship taking into account factors such as peer estimates of technology lives and customer lives as well as the Company's own historical data. Applying the practical expedient in ASC 340-40-25-4, the Company expenses commissions related to contract renewals with a renewal contract term of one year or less. The current and noncurrent portions of deferred commissions are included in prepaid expenses and other current assets, and other noncurrent assets, respectively, in its condensed consolidated balance sheets.
Recently adopted Accounting Pronouncements and Recent Accounting Pronouncements	In January 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, which impacts certain aspects of recognition, measurement, presentation and disclosure of financial instruments. The ASU impacts the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. The Company adopted this ASU in its first quarter of 2018. The adoption of this ASU did not have a material impact on the Company's condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force), to provide guidance on the presentation of certain cash receipts and cash payments in the statement of cash flows in order to reduce diversity in existing practice. The Company adopted this ASU in its first quarter of 2018. The adoption of this ASU did not have a material impact on the Company's condensed consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The update provides guidance on the presentation of restricted cash or restricted cash equivalents in the statement of cash flows. The Company adopted this ASU retrospectively in its first quarter of 2018. The Company reclassified restricted cash of $1.2 million for each of the six months ended June 30, 2018 and 2017, in the condensed consolidated statements of cash flows. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which revises the definition of a business and provides new guidance in evaluating when a set of transferred assets and activities is a business. The Company adopted this ASU prospectively in its first quarter of 2018. The adoption of this ASU did not have a material impact on the Company's condensed consolidated financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize all leases, including operating leases, on the balance sheet as a lease asset or lease liability, unless the lease is a short-term lease. ASU 2016-02 also requires additional disclosures regarding leasing arrangements. ASU 2016-02 is effective for the Company beginning in the first quarter of fiscal 2019 and early adoption is permitted. Pursuant to the leasing criteria, most of the Company's leased space and equipment leases will be required to be accounted for as capitalized assets on the balance sheet with offsetting financing obligations. In the statement of operations, what was formerly rent expense will be bifurcated into depreciation and interest expense. The Company is currently evaluating the impact and expects the ASU will have a material impact on its condensed consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment (Topic 350). This standard eliminates Step 2 from the goodwill impairment test, instead requiring an entity to recognize a goodwill impairment charge for the amount by which the goodwill carrying amount exceeds the reporting unit’s fair value. This ASU is effective for interim and annual goodwill impairment tests in fiscal years beginning after December 15, 2019 with early adoption permitted. This ASU must be applied on a prospective basis. The adoption of this ASU is not expected to have a material impact on the Company's condensed consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This ASU eliminates the stranded tax effects in other comprehensive income resulting from the Tax Cuts and Jobs Act (the "2017 Tax Act”). Because the amendments only relate to the reclassification of the income tax effects of the 2017 Tax Act, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. ASU 2018-02 is effective for the Company beginning in the first quarter of fiscal 2019 and early adoption is permitted. The Company is currently evaluating the impact of this ASU on its condensed consolidated financial statements.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. For certain of the Company’s financial instruments, including certain cash equivalents, accounts receivable, accounts payable, and other current liabilities, the carrying amounts approximate their fair values due to the relatively short maturity of these balances. The Company measures and reports certain cash equivalents, marketable securities and derivative foreign currency forward contracts at fair value in accordance with the provisions of the authoritative accounting guidance that addresses fair value measurements. This guidance establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. The hierarchy is broken down into three levels based on the reliability of inputs as follows: Level 1—Valuations based on quoted prices in active markets for identical assets or liabilities. Level 2—Valuations based on other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Valuations based on inputs that are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The Company's financial instruments consist of assets and liabilities measured using Level 1 and 2 inputs. Level 1 assets include a highly liquid money market fund, which is valued using unadjusted quoted prices that are available in an active market for an identical asset. Level 2 assets include fixed-income U.S. government agency securities, commercial paper, corporate bonds, asset-backed securities and derivative financial instruments consisting of foreign currency forward contracts. The securities, bonds and commercial paper are valued using prices from independent pricing services based on quoted prices in active markets for similar instruments or on industry models using data inputs such as interest rates and prices that can be directly observed or corroborated in active markets. The foreign currency forward contracts are valued using observable inputs, such as quotations on forward foreign exchange points and foreign interest rates.

Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of Cash and Cash Equivalents, Available-for-sale Securities Reconciliation

The Company's cash and cash equivalents, and marketable securities consist of the following:



	June 30, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	74,427	$	—	$	—		$	74,427
Money market funds	421		—		—			421
Commercial paper	11,931		—		—			11,931
Total	86,779		—		—			86,779
Short-term marketable securities:
Commercial paper	16,816		2		(1		)	16,817
Corporate bonds	37,917		1		(127		)	37,791
U.S. government agencies	181,338		—		(206		)	181,132
Total	236,071		3		(334		)	235,740
Long-term marketable securities:
Asset-backed securities	13,960		—		(38		)	13,922
U.S. government agencies	18,795		7		(71		)	18,731
Corporate bonds	31,902		3		(343		)	31,562
Total	64,657		10		(452		)	64,215
Total	$	387,507	$	13	$	(786	)	$	386,734



	December 31, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	86,500	$	—	$	—		$	86,500
Money market funds	91		—		—			91
Total	86,591		—		—			86,591
Short-term marketable securities:
Commercial paper	12,623		—		(3		)	12,620
Corporate bonds	38,425		1		(64		)	38,362
U.S. government agencies	151,058		—		(217		)	150,841
Total	202,106		1		(284		)	201,823
Long-term marketable securities:
Asset-backed securities	4,998		—		(12		)	4,986
U.S. government agencies	24,269		—		(54		)	24,215
Corporate bonds	38,198		—		(175		)	38,023
Total	67,465		—		(241		)	67,224
Total	$	356,162	$	1	$	(525	)	$	355,638

Schedule of changes to accumulated other comprehensive income

The following table shows the changes to accumulated other comprehensive loss for the six months ended June 30, 2018 (in thousands):



	Unrealized (Loss) Gain, net
Balance at December 31, 2017	$	(574	)
Change in net unrealized loss on available-for-sale marketable securities, net of tax	(342		)
Amounts reclassified for net realized gain included in net income, net of tax	95
Other comprehensive loss, net of tax	(247		)
Balance at June 30, 2018	$	(821	)

Schedule of Assets Measured on Recurring Basis



	June 30, 2018
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	28,749	$	—	$	28,749
U.S. government agencies	—		199,862		—		199,862
Corporate bonds	—		69,353		—		69,353
Asset-backed securities	—		13,922		—		13,922
Total	$	—	$	311,886	$	—	$	311,886



	December 31, 2017
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	12,620	$	—	$	12,620
U.S. government agencies	—		175,056		—		175,056
Corporate bonds	—		76,385		—		76,385
Asset-backed securities	—		4,986		—		4,986
Total	$	—	$	269,047	$	—	$	269,047

Schedule of Available-for-Sale Securities by Contractual Maturity

The following summarizes the fair value of marketable securities classified as available-for-sale by contractual, or effective, maturity:



	June 30, 2018
	Mature within One Year		Mature after One Year through Two Years		Mature over Two Years		Fair Value
	(in thousands)
Commercial paper	$	28,749	$	—	$	—	$	28,749
U.S. government agencies	181,132		18,730		—		199,862
Corporate bonds	37,791		31,268		294		69,353
Asset-backed securities	13,439		483		—		13,922
Total	$	261,111	$	50,481	$	294	$	311,886

Summary of Gains (Losses) Recognized From Forward Contracts and Other Foreign Currency Transactions



	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2018			2017			2018			2017
	(in thousands)
Net gain (loss) from forward contracts	$	931		$	(865	)	$	353		$	(1,122	)
Other foreign currency transactions (loss) gain	(1,398		)	733			(588		)	993
Total foreign exchange loss, net	$	(467	)	$	(132	)	$	(235	)	$	(129	)

- Definition

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

+ References + Details

Property and Equipment, Net (Tables)

6 Months Ended

Jun. 30, 2018

Property, Plant and Equipment [Abstract]

Property and equipment, net

Property and equipment, net, which includes assets under capital lease, consists of the following:



	June 30,			December 31,
	2018			2017
	(in thousands)
Computer equipment	$	85,527		$	77,883
Computer software	25,964			20,447
Furniture, fixtures and equipment	5,458			5,075
Assets under capital lease	3,503			—
Scanner appliances	15,234			14,325
Leasehold improvements	16,348			16,067
Total property and equipment	152,034			133,797
Less: accumulated depreciation and amortization	(87,061		)	(75,240		)
Property and equipment, net	$	64,973		$	58,557

Revenue from Contracts with Customers (Tables)

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Commission asset balances

Commission asset balances are as follows (in thousands):



	June 30, 2018		January 1, 2018
Commission asset, current	$	1,004	$	704
Commission asset, noncurrent	$	3,503	$	2,819

Contract liabilities

ontract liabilities (deferred revenue) balances are as follows (in thousands):



	June 30, 2018
	ASC 606		Operating Leases		Total
Deferred revenue, current	$	138,142	$	13,277	$	151,419
Deferred revenue, noncurrent	11,894		1,433		13,327
Total	$	150,036	$	14,710	$	164,746

	January 1, 2018
	ASC 606		Operating Leases		Total
Deferred revenue, current	$	130,579	$	12,607	$	143,186
Deferred revenue, noncurrent	15,419		1,717		17,136
Total	$	145,998	$	14,324	$	160,322

Accounts receivable, net

Accounts receivable, net, consists of the following (in thousands):



	June 30, 2018			January 1, 2018
ASC 606 receivables	$	49,839		$	60,984
Operating lease receivables	3,444			4,244
Less: allowance for doubtful accounts	(748		)	(816		)
Total accounts receivable, net	$	52,535		$	64,412

Expected revenue from contracts

The following table sets forth the expected revenue from all remaining performance obligations as of June 30, 2018 (in thousands):



	ASC 606 Revenues		Operating Lease Revenues		Total Revenues
2018 (remaining six months)	$	4,548	$	158	$	4,706
2019	13,608		1,060		14,668
2020	9,260		526		9,786
2021	3,260		111		3,371
2022	1,974		20		1,994
2023 and thereafter	1,370		4		1,374
Total	$	34,020	$	1,879	$	35,899

Revenue by sales channel

Revenues by sales channel are as follows (in thousands):



	Three Months Ended June 30, 2018						Six Months Ended June 30, 2018
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
Direct	$	31,896	$	3,398	$	35,294	$	66,864	$	7,140	$	74,004
Partner	30,330		2,529		32,859		54,565		4,462		59,027
Total	$	62,226	$	5,927	$	68,153	$	121,429	$	11,602	$	133,031

	Three Months Ended June 30, 2017						Six Months Ended June 30, 2017
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
Direct	$	29,144	$	3,539	$	32,683	$	56,764	$	6,933	$	63,697
Partner	20,840		1,779		22,619		41,099		3,627		44,726
Total	$	49,984	$	5,318	$	55,302	$	97,863	$	10,560	$	108,423

, are as follows (in thous

Goodwill and Intangible Assets, Net (Tables)

6 Months Ended

Jun. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Carrying value of intangible assets

The carrying values of intangible assets are as follows (in thousands, except for years):



					June 30, 2018
	Weighted Average Life (Years)	Weighted Average Remaining Life (Years)	Cost		Accumulated Amortization			Net Book Value
Developed technology	5	4.1	$	15,856	$	(1,907	)	$	13,949
Patent licenses	14	6.1	1,388		(772		)	616
Total intangibles subject to amortization			$	17,244	$	(2,679	)	14,565
Intangible assets not subject to amortization								40
Total intangible assets, net								$	14,605

					December 31, 2017
	Weighted Average Life (Years)	Weighted Average Remaining Life (Years)	Cost		Accumulated Amortization			Net Book Value
Developed technology	5	4.8	$	14,067	$	(2,371	)	$	11,696
Patent Licenses	14	6.7	1,388		(723		)	665
Total intangibles subject to amortization			$	15,455	$	(3,094	)	12,361
Intangible assets not subject to amortization								40
Total intangible assets, net								$	12,401

Intangible assets future periods amortization expense

As of June 30, 2018, the Company expects amortization expense in future periods to be as follows (in thousands

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments for Operating Leases

The following are the minimum annual lease payments due under these leases at June 30, 2018 (in thousands):



	Operating Leases		Capital Leases
	(in thousands)
2018 (remaining six months)	$	4,997	$	885
2019	6,098		1,770
2020	5,747		130
2021	5,030		54
2022	4,547		—
2023 and thereafter	23,609		—
Total minimum lease payments	$	50,028	2,839
Less: amount representing interest			(131		)
Present value of minimum payments			2,708
Less: current portion			(1,667		)
Capital lease obligations, noncurrent			$	1,041

Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

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

Employee stock-based compensation

The following table shows a summary of the stock-based compensation expense included in the condensed consolidated statements of operations for the three and six months ended June 30, 2018 and 2017:



	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
	(in thousands)
Cost of revenues	$	609	$	536	$	1,263	$	1,037
Research and development	1,976		1,505		3,817		2,726
Sales and marketing	1,105		1,129		2,506		2,213
General and administrative	3,333		3,277		8,328		4,803
Total stock-based compensation	$	7,023	$	6,447	$	15,914	$	10,779

Stock option activity

A summary of the Company’s stock option activity is as follows:



	Outstanding Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
						(in thousands)
Balance as of December 31, 2017	4,495,891		$	25.29	6.6	$	153,129
Granted	154,025		$	71.26
Exercised	(430,848	)	$	28.25
Canceled	(164,766	)	$	38.38
Balance as of June 30, 2018	4,054,302		$	26.19	6.3	$	235,597
Vested and expected to vest - June 30, 2018	3,863,453		$	25.32	6.2	$	227,859
Exercisable - June 30, 2018	2,921,338		$	22.06	5.5	$	181,818

Restricted stock units activity

A summary of the Company’s RSU and RSA activity is as follows:



	Outstanding RSUs and RSAs		Weighted Average Grant Date Fair Value Per Share

Balance as of December 31, 2017	1,410,588		$	40.34
Granted	188,752		$	71.11
Vested	(342,569	)	$	38.74
Canceled	(121,470	)	$	40.55
Balance as of June 30, 2018	1,135,301		$	45.92
Outstanding and expected to vest - June 30, 2018	980,802		$	45.32

Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The computations for basic and diluted net income per share are as follows:



	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
	(in thousands, except per share data)
Numerator:
Net income	$	10,293	$	7,202	$	19,435	$	29,132
Denominator:
Weighted-average shares used in computing net income per share:
Basic	38,987		37,277		38,843		36,887
Effect of potentially dilutive securities:
Common stock options	2,610		2,003		2,576		2,110
Restricted stock units	618		255		655		210
Diluted	42,215		39,535		42,074		39,207
Net income per share:
Basic	$	0.26	$	0.19	$	0.50	$	0.79
Diluted	$	0.24	$	0.18	$	0.46	$	0.74

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

Potentially dilutive securities not included in the calculation of diluted net income per share because doing so would be antidilutive are as follows:



	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2018	2017	2018	2017
	(in thousands)
Common stock options	125	1,261	81	1,307
Restricted stock units	2	9	30	6
	127	1,270	111	1,313

Segment Information and Information about Geographic Area (Tables)

6 Months Ended

Jun. 30, 2018

Segment Reporting [Abstract]

Revenues be geographic area

Revenues by sales channel are as follows (in thousands):



	Three Months Ended June 30, 2018						Six Months Ended June 30, 2018
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
Direct	$	31,896	$	3,398	$	35,294	$	66,864	$	7,140	$	74,004
Partner	30,330		2,529		32,859		54,565		4,462		59,027
Total	$	62,226	$	5,927	$	68,153	$	121,429	$	11,602	$	133,031

	Three Months Ended June 30, 2017						Six Months Ended June 30, 2017
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
Direct	$	29,144	$	3,539	$	32,683	$	56,764	$	6,933	$	63,697
Partner	20,840		1,779		22,619		41,099		3,627		44,726
Total	$	49,984	$	5,318	$	55,302	$	97,863	$	10,560	$	108,423

, are as follows (in thous

Revenues and property and equipment, net, by geographic area

ds):



	Three Months Ended June 30, 2018						Six Months Ended June 30, 2018
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
United States	$	41,675	$	4,124	$	45,799	$	81,983	$	8,130	$	90,113
Foreign	20,551		1,803		22,354		39,446		3,472		42,918
Total	$	62,226	$	5,927	$	68,153	$	121,429	$	11,602	$	133,031

	Three Months Ended June 30, 2017						Six Months Ended June 30, 2017
	ASC 606 Revenues		Operating Lease Revenues		Total Revenues		ASC 606 Revenues		Operating Lease Revenues		Total Revenues
United States	$	35,268	$	3,770	$	39,038	$	69,150	$	7,349	$	76,499
Foreign	14,716		1,548		16,264		28,713		3,211		31,924
Total	$	49,984	$	5,318	$	55,302	$	97,863	$	10,560	$	108,423

Property and equipment, net, by geographic area, are as fo

The Company and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Reclassification
Investment in privately held company	$ 2,500		$ 0
Retained earnings	45,795		39,924
Commission Expense	500
Restricted cash	$ 1,200		$ 1,200
Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606
Reclassification
Retained earnings		$ 2,700
Commission asset balance		3,500
Deferred tax liability		$ 800

Fair Value of Financial Instruments - Cash and Cash Equivalents, Available-for-sale Securities Reconciliation (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	$ 387,507	$ 356,162
Unrealized Gains	13	1
Unrealized Losses	(786)	(525)
Fair Value	386,734	355,638
Cash and cash equivalents
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	86,779	86,591
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	86,779	86,591
Short-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	236,071	202,106
Unrealized Gains	3	1
Unrealized Losses	(334)	(284)
Fair Value	235,740	201,823
Long-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	64,657	67,465
Unrealized Gains	10	0
Unrealized Losses	(452)	(241)
Fair Value	64,215	67,224
Cash \| Cash and cash equivalents
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	74,427	86,500
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	74,427	86,500
Money market funds \| Cash and cash equivalents
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	421	91
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	421	91
Commercial paper \| Cash and cash equivalents
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	11,931
Unrealized Gains	0
Unrealized Losses	0
Fair Value	11,931
Commercial paper \| Short-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	16,816	12,623
Unrealized Gains	2	0
Unrealized Losses	(1)	(3)
Fair Value	16,817	12,620
Corporate bonds \| Short-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	37,917	38,425
Unrealized Gains	1	1
Unrealized Losses	(127)	(64)
Fair Value	37,791	38,362
Corporate bonds \| Long-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	31,902	38,198
Unrealized Gains	3	0
Unrealized Losses	(343)	(175)
Fair Value	31,562	38,023
Asset backed securities \| Long-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	13,960	4,998
Unrealized Gains	0	0
Unrealized Losses	(38)	(12)
Fair Value	13,922	4,986
US government agencies \| Short-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	181,338	151,058
Unrealized Gains	0	0
Unrealized Losses	(206)	(217)
Fair Value	181,132	150,841
US government agencies \| Long-term investments
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Amortized Cost	18,795	24,269
Unrealized Gains	7	0
Unrealized Losses	(71)	(54)
Fair Value	$ 18,731	$ 24,215

Fair Value of Financial Instruments - Changes in Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 343,544
Change in net unrealized loss on available-for-sale marketable securities, net of tax	$ 65	$ (29)	(342)	$ (80)
Amounts reclassified for net realized gain included in net income, net of tax	79	$ 20	95	$ 2
Ending balance	365,239		365,239
Unrealized Gain (Loss) on Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(574)
Change in net unrealized loss on available-for-sale marketable securities, net of tax			(342)
Amounts reclassified for net realized gain included in net income, net of tax			95
Other comprehensive income (loss), net			(247)
Ending balance	$ (821)		$ (821)

Fair Value of Financial Instruments - Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	$ 311,886
Level 1 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	$ 0
Level 2 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	311,886	269,047
Level 3 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	28,749
Commercial paper \| Level 1 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Commercial paper \| Level 2 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	28,749	12,620
Commercial paper \| Level 3 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
US government agencies
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	199,862
US government agencies \| Level 1 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
US government agencies \| Level 2 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	199,862	175,056
US government agencies \| Level 3 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	69,353
Corporate bonds \| Level 1 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Corporate bonds \| Level 2 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	69,353	76,385
Corporate bonds \| Level 3 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Asset backed securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	13,922
Asset backed securities \| Level 1 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Asset backed securities \| Level 2 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	13,922	4,986
Asset backed securities \| Level 3 \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	0	0
Fair Value \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	311,886	269,047
Fair Value \| Commercial paper \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	28,749	12,620
Fair Value \| US government agencies \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	199,862	175,056
Fair Value \| Corporate bonds \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	69,353	76,385
Fair Value \| Asset backed securities \| Recurring Basis
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities, fair value	$ 13,922	$ 4,986

Fair Value of Financial Instruments - Contractual Maturity (Details) $ in Thousands	Jun. 30, 2018 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Mature within One Year	$ 261,111
Mature after One Year through Two Years	50,481
Mature over Two Years	294
Fair Value	311,886
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Mature within One Year	28,749
Mature after One Year through Two Years	0
Mature over Two Years	0
Fair Value	28,749
US government agencies
Schedule of Available-for-sale Securities [Line Items]
Mature within One Year	181,132
Mature after One Year through Two Years	18,730
Mature over Two Years	0
Fair Value	199,862
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Mature within One Year	37,791
Mature after One Year through Two Years	31,268
Mature over Two Years	294
Fair Value	69,353
Asset backed securities
Schedule of Available-for-sale Securities [Line Items]
Mature within One Year	13,439
Mature after One Year through Two Years	483
Mature over Two Years	0
Fair Value	$ 13,922

Fair Value of Financial Instruments - Derivatives (Details) € in Millions, £ in Millions	Jun. 30, 2018 GBP (£) contract	Jun. 30, 2018 EUR (€) contract	Jun. 30, 2018 USD ($) contract	Dec. 31, 2017 GBP (£) contract	Dec. 31, 2017 EUR (€) contract	Dec. 31, 2017 USD ($) contract
Derivatives, Fair Value [Line Items]
Foreign currency contract, asset, fair value disclosure						$ 0
Forward Contracts
Derivatives, Fair Value [Line Items]
Derivative, number of instruments held \| contract	2	2	2	2	2	2
Derivative, notional amount	£ 4.8	€ 10.6		£ 4.8	€ 7.0
Foreign currency contract, asset, fair value disclosure			$ 0

Fair Value of Financial Instruments - Gains (Losses) Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Other foreign currency transactions (loss) gain	$ (1,398)	$ 733	$ (588)	$ 993
Total foreign exchange loss, net	(467)	(132)	(235)	(129)
Forward Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) from forward contracts	$ 931	$ (865)	$ 353	$ (1,122)

Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment	$ 152,034		$ 152,034		$ 133,797
Less: accumulated depreciation and amortization	(87,061)		(87,061)		(75,240)
Property and equipment, net	64,973		64,973		58,557
Depreciation and amortization expense	6,400	$ 4,900	12,800	$ 9,600
Capital leases, accumulated depreciation	500		500
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	85,527		85,527		77,883
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment	25,964		25,964		20,447
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property and equipment	5,458		5,458		5,075
Assets under capital lease
Property, Plant and Equipment [Line Items]
Property and equipment	3,503		3,503		0
Scanner appliances
Property, Plant and Equipment [Line Items]
Property and equipment	15,234		15,234		14,325
Scanner appliances and other computer equipment subject to subscription
Property, Plant and Equipment [Line Items]
Property and equipment, net	7,600		7,600		6,800
Scanner appliances and other computer equipment not placed in service
Property, Plant and Equipment [Line Items]
Property and equipment	1,100		1,100		900
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 16,348		$ 16,348		$ 16,067

Revenue from Contracts with Customers - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 45,795,000		$ 45,795,000			$ 39,924,000
Amortization of commissions assets	300,000		500,000
Capitalized contract costs		$ 0		$ 0
Revenue recognized	68,153,000	$ 55,302,000	133,031,000	$ 108,423,000
Unbilled contracts	35,899,000		$ 35,899,000
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue recognized	$ 98,400,000
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings					$ 2,700,000
Commission asset balance					3,500,000
Deferred tax liability					$ 800,000

Revenue from Contracts with Customers - Commission Asset Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018
Revenue from Contract with Customer [Abstract]
Commission asset, current	$ 1,004	$ 704
Commission asset, noncurrent	$ 3,503	$ 2,819

Revenue from Contracts with Customers - Deferred Revenues (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Deferred revenue, current	$ 151,419	$ 143,186	$ 143,186
Deferred revenue, noncurrent	13,327	17,136	$ 17,136
Total	164,746	160,322
ASC 606
Deferred Revenue Arrangement [Line Items]
Deferred revenue, current	138,142	130,579
Deferred revenue, noncurrent	11,894	15,419
Total	150,036	145,998
Operating Leases
Deferred Revenue Arrangement [Line Items]
Deferred revenue, current	13,277	12,607
Deferred revenue, noncurrent	1,433	1,717
Total	$ 14,710	$ 14,324

- Definition

The carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income.

+ References + Details

- Definition

The noncurrent portion of deferred revenue amount as of balance sheet date. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References + Details

Revenue from Contracts with Customers - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
ASC 606 receivables	$ 49,839	$ 60,984
Operating lease receivables	3,444	4,244
Allowance for doubtful accounts receivable	(748)	(816)	$ (816)
Total accounts receivable, net	$ 52,535	$ 64,412	$ 64,412

Revenue from Contracts with Customers - Unbilled contracts (Details) $ in Thousands	Jun. 30, 2018 USD ($)
Deferred Revenue Arrangement [Line Items]
Contracts expected to be billed remainder of year	$ 4,706
Unbilled Receivables, Expected To Be Billed In 2019	14,668
Unbilled Receivables, Expected To Be Billed In 2020	9,786
Unbilled Receivables, Expected To Be Billed In 2021	3,371
Unbilled Receivables, Expected To Be Billed In 2022	1,994
Unbilled Receivables, Expected To Be Billed Thereafter	1,374
Unbilled Receivables, Not Billable	35,899
ASC 606
Deferred Revenue Arrangement [Line Items]
Contracts expected to be billed remainder of year	4,548
Unbilled Receivables, Expected To Be Billed In 2019	13,608
Unbilled Receivables, Expected To Be Billed In 2020	9,260
Unbilled Receivables, Expected To Be Billed In 2021	3,260
Unbilled Receivables, Expected To Be Billed In 2022	1,974
Unbilled Receivables, Expected To Be Billed Thereafter	1,370
Unbilled Receivables, Not Billable	34,020
Operating Lease Revenues
Deferred Revenue Arrangement [Line Items]
Contracts expected to be billed remainder of year	158
Unbilled Receivables, Expected To Be Billed In 2019	1,060
Unbilled Receivables, Expected To Be Billed In 2020	526
Unbilled Receivables, Expected To Be Billed In 2021	111
Unbilled Receivables, Expected To Be Billed In 2022	20
Unbilled Receivables, Expected To Be Billed Thereafter	4
Unbilled Receivables, Not Billable	$ 1,879

Revenue from Contracts with Customers - Revenue by sales channel (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 68,153	$ 55,302	$ 133,031	$ 108,423
Direct
Disaggregation of Revenue [Line Items]
Revenues	35,294	32,683	74,004	63,697
Partner
Disaggregation of Revenue [Line Items]
Revenues	32,859	22,619	59,027	44,726
ASC 606
Disaggregation of Revenue [Line Items]
Revenues	62,226	49,984	121,429	97,863
ASC 606 \| Direct
Disaggregation of Revenue [Line Items]
Revenues	31,896	29,144	66,864	56,764
ASC 606 \| Partner
Disaggregation of Revenue [Line Items]
Revenues	30,330	20,840	54,565	41,099
Operating Lease Revenues
Disaggregation of Revenue [Line Items]
Revenues	5,927	5,318	11,602	10,560
Operating Lease Revenues \| Direct
Disaggregation of Revenue [Line Items]
Revenues	3,398	3,539	7,140	6,933
Operating Lease Revenues \| Partner
Disaggregation of Revenue [Line Items]
Revenues	$ 2,529	$ 1,779	$ 4,462	$ 3,627

Business Combination - Narrative (Details) - USD ($) $ in Thousands	Apr. 01, 2018	Jun. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 1,849	$ 1,549
1Mobility
Business Acquisition [Line Items]
Total purchase price	$ 4,000
Deferred consideration	600
Technology-based intangible assets	3,700
Goodwill	$ 300
Estimated useful life of technology-based intangible assets	15 years

Goodwill and Intangible Assets, Net - Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Schedule of Goodwill and Intangible Assets [Line Items]
Cost	$ 17,244		$ 17,244		$ 15,455
Accumulated Amortization	(2,679)		(2,679)		(3,094)
Net Book Value	14,565		14,565		12,361
Intangible assets not subject to amortization	40		40		40
Total intangible assets, net	14,605		14,605		12,401
Amortization of intangible assets	900	$ 100	1,500	$ 200
Goodwill	1,849		$ 1,849		1,549
Developed technology
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted Average Life (Years)			5 years
Weighted Average Remaining Life (Years)			4 years 1 month 10 days	4 years 9 months 15 days
Cost	15,856		$ 15,856		14,067
Accumulated Amortization	(1,907)		(1,907)		(2,371)
Net Book Value	13,949		$ 13,949		11,696
Patent licenses
Schedule of Goodwill and Intangible Assets [Line Items]
Weighted Average Life (Years)			14 years
Weighted Average Remaining Life (Years)			6 years 1 month 13 days	6 years 7 months 29 days
Cost	1,388		$ 1,388		1,388
Accumulated Amortization	(772)		(772)		(723)
Net Book Value	$ 616		$ 616		$ 665

Goodwill and Intangible Assets, Net - Future Amortization (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
2018 (remaining six months)	$ 1,729
2018	3,456
2019	3,456
2020	3,456
2021	2,302
2023 and thereafter	166
Net Book Value	$ 14,565	$ 12,361

Commitments and Contingencies - Lease Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2018	Dec. 31, 2017	Oct. 14, 2016
Commitments and Contingencies Disclosure [Abstract]
Financing arrangement for data center storage equipment						$ 3,500
Arrangement interest rate	5.00%
Rent expense		$ 2,400	$ 2,400	$ 4,600	$ 4,300
Deferred rent credit		11,100		11,100			$ 9,500
Operating Leased Assets]
Total lease commitment		50,028		$ 50,028
Headquarter Office Facility
Operating Leased Assets]
Lease term (in years)				10 years
Total lease commitment		$ 38,600		$ 38,600
Standby letter of credit
Operating Leased Assets]
Letter of credit to secure the Company's lease obligations								$ 1,200

Commitments and Contingencies - Schedule of Leases (Details) $ in Thousands	Jun. 30, 2018 USD ($)
Operating Leases
2018 (remaining six months)	$ 4,997
2019	6,098
2020	5,747
2021	5,030
2022	4,547
2023 and thereafter	23,609
Total minimum lease payments	50,028
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018 (remaining six months)	885
2019	1,770
2020	130
2021	54
2022	0
2023 and thereafter	0
Total minimum lease payments	2,839
Less: amount representing interest	(131)
Present value of minimum payments	2,708
Less: current portion	(1,667)
Capital lease obligations, noncurrent	$ 1,041

Stock-based Compensation - Stock Options (Details)	Jun. 30, 2018 shares
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	11,791,139
Number of shares available for grant	4,211,131
2000 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant	0

Stock-based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	$ 7,023	$ 6,447	$ 15,914	$ 10,779
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized employee compensation cost	14,000		$ 14,000
Unrecognized employee compensation cost, period for recognition			2 years 2 months 12 days
Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized employee compensation cost	42,100		$ 42,100
Unrecognized employee compensation cost, period for recognition			2 years 10 months 24 days
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	609	536	$ 1,263	1,037
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	1,976	1,505	3,817	2,726
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	1,105	1,129	2,506	2,213
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total employee stock-based compensation	$ 3,333	$ 3,277	$ 8,328	$ 4,803

Stock-based Compensation - Stock Option Plan Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Outstanding Shares
Beginning balance (in shares)	4,495,891
Granted (in shares)	154,025
Exercised (in shares)	(430,848)
Canceled (in shares)	(164,766)
Ending balance (in shares)	4,054,302
Vested and expected to vest (in shares)	3,863,453
Exercisable (in shares)	2,921,338
Weighted Average Exercise Price
Weighted average exercise price, Beginning balance (in dollars per share)	$ 25.29
Weighted average exercise price, granted (in dollars per share)	71.26
Weighted average exercise price, exercised (in dollars per share)	28.25
Weighted average exercise price, canceled (in dollars per share)	38.38
Weighted average exercise price, Ending balance (in dollars per share)	26.19
Weighted average exercise price, Vested and expected to vest (in dollars per share)	25.32
Weighted average exercise price, Exercisable (in dollars per share)	$ 22.06
Weighted Average Remaining Contractual Life
Weighted average remaining contractual life (in years)	6 years 3 months 7 days	6 years 7 months 6 days
Weighted Average Remaining Contractual Life (Years), Vested and Expected to Vest	6 years 1 month 28 days
Weighted Average Remaining Contractual Life (Years), Exercisable	5 years 6 months 11 days
Aggregate Intrinsic Value
Aggregate intrinsic value	$ 235,597		$ 153,129
Aggregate intrinsic value, Vested and expected to vest	227,859
Aggregate intrinsic value, Exercisable	$ 181,818

Stock-based Compensation - Restricted Stock (Details) - Restricted Stock Units	6 Months Ended
	Jun. 30, 2018 $ / shares shares
Outstanding RSUs and RSAs
Beginning balance (in shares) \| shares	1,410,588
Granted (in shares) \| shares	188,752
Released (in shares) \| shares	(342,569)
Canceled (in shares) \| shares	(121,470)
Ending balance (in shares) \| shares	1,135,301
Outstanding and expected to vest (in shares) \| shares	980,802
Weighted Average Fair Value
Beginning balance (usd per share) \| $ / shares	$ 40.34
Granted (usd per share) \| $ / shares	71.11
Released (usd per share) \| $ / shares	38.74
Canceled (usd per share) \| $ / shares	40.55
Ending balance (usd per share) \| $ / shares	45.92
Outstanding and expected to vest (usd per share) \| $ / shares	$ 45.32

Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income	$ 10,293	$ 7,202	$ 19,435	$ 29,132
Denominator:
Basic (shares)	38,987	37,277	38,843	36,887
Common stock options (shares)	2,610	2,003	2,576	2,110
Restricted stock units (shares)	618	255	655	210
Diluted (shares)	42,215	39,535	42,074	39,207
Basic (USD per share)	$ 0.26	$ 0.19	$ 0.50	$ 0.79
Diluted (USD per share)	$ 0.24	$ 0.18	$ 0.46	$ 0.74
Antidilutive Securities
Antidilutive securities (shares)	127	1,270	111	1,313
Stock Options
Antidilutive Securities
Antidilutive securities (shares)	125	1,261	81	1,307
Restricted Stock Units
Antidilutive Securities
Antidilutive securities (shares)	2	9	30	6

Stockholder's Equity (Details) - USD ($)	3 Months Ended
Stockholder's Equity (Details) - USD ($)	Jun. 30, 2018	Feb. 05, 2018
Equity [Abstract]
Share repurchase program, authorized amount		$ 100,000,000
Shares repurchased during period (in shares)	256,827
Shares repurchased during period, value	$ 19,400,000
Remaining authorized amount	$ 80,600,000

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provision for (benefit from) income taxes	$ 1,486	$ 2,167	$ 1,995	$ (11,654)
Effective tax rate	12.60%	23.10%	9.30%	(66.70%)
Unrecognized Tax Benefits	$ 5,600		$ 5,600		$ 5,100
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 3,100		$ 3,100		$ 2,800

Segment Information and Information about Geographic Area - Revenue by geographic area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 68,153	$ 55,302	$ 133,031	$ 108,423
United States
Disaggregation of Revenue [Line Items]
Revenues	45,799	39,038	90,113	76,499
Foreign
Disaggregation of Revenue [Line Items]
Revenues	22,354	16,264	42,918	31,924
ASC 606
Disaggregation of Revenue [Line Items]
Revenues	62,226	49,984	121,429	97,863
ASC 606 \| United States
Disaggregation of Revenue [Line Items]
Revenues	41,675	35,268	81,983	69,150
ASC 606 \| Foreign
Disaggregation of Revenue [Line Items]
Revenues	20,551	14,716	39,446	28,713
Operating Lease Revenues
Disaggregation of Revenue [Line Items]
Revenues	5,927	5,318	11,602	10,560
Operating Lease Revenues \| United States
Disaggregation of Revenue [Line Items]
Revenues	4,124	3,770	8,130	7,349
Operating Lease Revenues \| Foreign
Disaggregation of Revenue [Line Items]
Revenues	$ 1,803	$ 1,548	$ 3,472	$ 3,211

Segment Information and Information about Geographic Area - Property and Equipment, net (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) segment	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments (in segment) \| segment	1
Property and equipment, net	$ 64,973	$ 58,557
United States
Segment Reporting Information [Line Items]
Property and equipment, net	55,596	50,785
Other
Segment Reporting Information [Line Items]
Property and equipment, net	$ 9,377	$ 7,772