The Company and Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2016
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”) was incorporated in the state of Delaware on December 30, 1999. The Company is headquartered in Redwood 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, 2015, 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 nine month periods ended September 30, 2016 are not necessarily indicative of the results of operations expected for the entire year ending December 31, 2016 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, 2015 filed with the SEC on February 26, 2016. Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries. All significant intercompany transactions and balances have been eliminated upon consolidation. Use of Estimates The preparation of the 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 contingent 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 condensed consolidated financial statements. Concentration of Credit Risk The Company invests its cash and cash equivalents with major financial institutions. Cash balances with any one institution at times may be in excess of federally insured limits. Cash equivalents are invested in high-quality investment grade financial instruments and are diversified. The Company has not experienced any losses in such accounts and believes it is not exposed to any significant credit risk. Credit risk with respect to accounts receivable is dispersed due to the large number of customers. Collateral is not required for accounts receivable. The Company maintains an allowance for potential credit losses based upon the expected collectability of accounts receivable. The Company writes off its receivables once collection efforts are unsuccessful. As of September 30, 2016, there is one customer with a multi-year contract that accounted for approximately 10% of the Company's accounts receivable balance. As of December 31, 2015, no customer or channel partner accounted for more than 10% of the Company's accounts receivable balance. Cash, Cash Equivalents, Short-Term and Long-Term Investments Cash and cash equivalents include cash held in banks, highly liquid money market funds, commercial paper and fixed-income U.S. government agency securities, all with original maturities of three months or less when acquired. The Company’s investments consist of fixed-income U.S. government agency securities, corporate bonds, asset-backed securities, and commercial paper. Management determines the appropriate classification of the Company's investments at the time of purchase and reevaluates such designation at each balance sheet date. The Company classifies its investments as either short-term or long-term based on each instrument's underlying contractual maturity date. Cash equivalents are stated at cost, which approximates fair market value. Short-term and long-term investments are classified as available-for-sale and are carried at fair value. Unrealized gains and losses in fair value are reported in other comprehensive income (loss). When the available-for-sale securities are sold, cost is based on the specific identification method, and the realized gains and losses are included in other income (expense) in the condensed consolidated statements of operations. Short-term and long-term investments are reviewed quarterly for impairment that is deemed to be other-than-temporary. An investment is considered other-than-temporarily impaired when its fair value is below its amortized cost and (1) there is an intent to sell the security, (2) it is “more likely than not” that the security will be sold before recovery of its amortized cost basis or (3) the present value of expected cash flows from the investment is not expected to recover the entire amortized cost basis. Declines in value that are considered to be other-than-temporary and adjustments to amortized cost for the amortization of premiums and the accretion of discounts are recorded in other income (expense). Interest and dividends are recorded in interest income as earned. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standard Update (“ASU”) amending revenue recognition guidance and requiring more detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The ASU will be effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, but entities will be permitted to early adopt the standard only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The new revenue standard may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized on date of adoption. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements. In January 2016, the FASB issued an ASU that will impact certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This guidance is effective for public business entities in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements. In February 2016, the FASB issued an ASU which requires, among other things, lease assets and lease liabilities arising from leases, including operating leases, to be recognized on the balance sheet. In addition, the ASU requires disclosing key information about leasing arrangements. This guidance supersedes existing lease guidance and is effective for public business entities in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements. In March 2016, the FASB issued an ASU intended to simplify and improve various aspects related to how employee-share based payment transactions are accounted for and presented in the financial statements. The ASU addresses income tax consequences, classification of awards as either equity or liabilities, classification on the statement of cash flows and forfeiture rate calculations. This guidance is effective for public business entities in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements.

The Company and Summary of Significant Accounting Policies

Description of Business

Qualys, Inc. (the “Company”) was incorporated in the state of Delaware on December 30, 1999. The Company is headquartered in Redwood 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, 2015, 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 nine month periods ended September 30, 2016 are not necessarily indicative of the results of operations expected for the entire year ending December 31, 2016 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, 2015 filed with the SEC on February 26, 2016.

Principles of Consolidation

The accompanying condensed consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries. All significant intercompany transactions and balances have been eliminated upon consolidation.

Use of Estimates

The preparation of the 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 contingent 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 condensed consolidated financial statements.

Concentration of Credit Risk

The Company invests its cash and cash equivalents with major financial institutions. Cash balances with any one institution at times may be in excess of federally insured limits. Cash equivalents are invested in high-quality investment grade financial instruments and are diversified. The Company has not experienced any losses in such accounts and believes it is not exposed to any significant credit risk.

Credit risk with respect to accounts receivable is dispersed due to the large number of customers. Collateral is not required for accounts receivable. The Company maintains an allowance for potential credit losses based upon the expected collectability of accounts receivable. The Company writes off its receivables once collection efforts are unsuccessful. As of September 30, 2016, there is one customer with a multi-year contract that accounted for approximately 10% of the Company's accounts receivable balance. As of December 31, 2015, no customer or channel partner accounted for more than 10% of the Company's accounts receivable balance.

Cash, Cash Equivalents, Short-Term and Long-Term Investments

Cash and cash equivalents include cash held in banks, highly liquid money market funds, commercial paper and fixed-income U.S. government agency securities, all with original maturities of three months or less when acquired. The Company’s investments consist of fixed-income U.S. government agency securities, corporate bonds, asset-backed securities, and commercial paper. Management determines the appropriate classification of the Company's investments at the time of purchase and reevaluates such designation at each balance sheet date. The Company classifies its investments as either short-term or long-term based on each instrument's underlying contractual maturity date.

Cash equivalents are stated at cost, which approximates fair market value. Short-term and long-term investments are classified as available-for-sale and are carried at fair value. Unrealized gains and losses in fair value are reported in other comprehensive income (loss). When the available-for-sale securities are sold, cost is based on the specific identification method, and the realized gains and losses are included in other income (expense) in the condensed consolidated statements of operations. Short-term and long-term investments are reviewed quarterly for impairment that is deemed to be other-than-temporary. An investment is considered other-than-temporarily impaired when its fair value is below its amortized cost and (1) there is an intent to sell the security, (2) it is “more likely than not” that the security will be sold before recovery of its amortized cost basis or (3) the present value of expected cash flows from the investment is not expected to recover the entire amortized cost basis. Declines in value that are considered to be other-than-temporary and adjustments to amortized cost for the amortization of premiums and the accretion of discounts are recorded in other income (expense). Interest and dividends are recorded in interest income as earned.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standard Update (“ASU”) amending revenue recognition guidance and requiring more detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The ASU will be effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, but entities will be permitted to early adopt the standard only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The new revenue standard may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized on date of adoption. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements.

In January 2016, the FASB issued an ASU that will impact certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This guidance is effective for public business entities in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements.

In February 2016, the FASB issued an ASU which requires, among other things, lease assets and lease liabilities arising from leases, including operating leases, to be recognized on the balance sheet. In addition, the ASU requires disclosing key information about leasing arrangements. This guidance supersedes existing lease guidance and is effective for public business entities in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements.

In March 2016, the FASB issued an ASU intended to simplify and improve various aspects related to how employee-share based payment transactions are accounted for and presented in the financial statements. The ASU addresses income tax consequences, classification of awards as either equity or liabilities, classification on the statement of cash flows and forfeiture rate calculations. This guidance is effective for public business entities in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements.