Basis of Presentation	3 Months Ended
Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	(a) The Company and Nature of Operations FalconStor Software, Inc., a Delaware Corporation (the "Company" or "FalconStor"), is a leading storage software company offering a converged data services software platform that is hardware agnostic. The Company develops, manufactures and sells data migration, business continuity, disaster recovery, optimized backup and de-duplication solutions and provides the related maintenance, implementation and engineering services. (b) Liquidity As of March 31, 2019, we had a working capital deficiency of $2.5 million, which is inclusive of current deferred revenue of $6.2 million, and a stockholders' deficit of $12.0 million. During the three months ended March 31, 2019, we had a net loss of $0.1 million and negative cash flow from operations of $0.1 million. Our cash and cash equivalents at March 31, 2019 was $2.4 million, a decrease of $0.7 million as compared to December 31, 2018. We believe that our cash flows from future operations and existing cash on hand are sufficient to conduct our planned operations and meet our contractual requirements for at least one year from the date of issuance of the accompanying consolidated financial statements. (c) Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. (d) Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company’s significant estimates include those related to revenue recognition, accounts receivable allowances, share-based payment compensation, valuation of derivatives, capitalizable software development costs, valuation of goodwill and other intangible assets and income taxes. During the first quarter of 2018, the Company also had significant estimates in the determination of the fair value of Series A Preferred Stock, notes payable and warrants issued. Actual results could differ from those estimates. The financial market volatility in many countries where the Company operates has impacted and may continue to impact the Company’s business. Such conditions could have a material impact on the Company’s significant accounting estimates discussed above. (e) Unaudited Interim Financial Information The accompanying unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations relating to interim financial statements. In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary to present fairly the financial position of the Company at March 31, 2019, and the results of its operations for the three months ended March 31, 2019 and 2018. The results of operations of any interim period are not necessarily indicative of the results of operations to be expected for the full fiscal year. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes set forth in the Company's Annual Report on Form 10-K for the year ended December 31, 2018 ("2018 Form 10-K"). (f) Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (the "FASB") issued ASU No. 2016-02, which establishes a right-of-use (ROU) model that requires a lessee to record a right of use (ROU) asset and a lease liability on the balance sheet for most leases. In July 2018, the FASB issued ASU No. 2018-11, which amends the guidance to add a method of adoption whereby the issuer may elect to recognize a cumulative effect adjustment at the beginning of the period of adoption. ASU No. 2018-11 does not require comparative period financial information to be adjusted. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. ASU 2016-02 defines a lease as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment for a period of time in exchange for consideration. To determine whether a contract conveys the right to control the use of the identified asset for a period of time, the customer has to have both (1) the right to obtain substantially all of the economic benefits from the use of the identified asset and (2) the right to direct the use of the identified asset, a contract does not contain an identified asset if the supplier has a substantive right to substitute such asset ("the leasing criteria"). We have determined that our real estate leases with terms in excess of one year and which do not include an option to purchase the underlying asset, meet the leasing criteria. On January 1, 2019, we adopted ASU No. 2016-02, applying the package of practical expedients to leases that commenced before the effective date whereby we elected to not reassess the following: (i) whether any expired or existing contracts contain leases; (ii) the lease classification for any expired or existing leases; and (iii) initial direct costs for any existing leases. We elected to apply the transition provisions as of January 1, 2019, the date of adoption, and we recorded lease ROU assets of $2.9 million and related liabilities of $3.6 million million on our balance sheet related to our operating leases. We have no financing leases. There was no change to our consolidated statements of operations or cash flows. In July 2018, the FASB issued ASU 2018-09, Codification Improvements. The amendments in ASU 2018-09 affect a wide variety of Topics in the FASB Codification and apply to all reporting entities within the scope of the affected accounting guidance. The Company has evaluated ASU 2018-09 in its entirety and determined that the amendments related to Topic 718-740, Compensation-Stock Compensation-Income Taxes, are the only provisions that currently apply to the Company. The amendments in ASU 2018-09 related to Topic 718-740, Compensation-Stock Compensation-Income Taxes, clarify that an entity should recognize excess tax benefits related to stock compensation transactions in the period in which the amount of the deduction is determined. On January 1, 2019, we adopted ASU 2018-09 and it did not have a material impact on the Company's 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, to expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees and supersedes the guidance in Subtopic 505-50, Equity - Equity-Based Payments to Non-Employees. Under ASU 2018-07, equity-classified nonemployee share-based payment awards are measured at the grant date fair value on the grant date. The probability of satisfying performance conditions must be considered for equity-classified nonemployee share-based payment awards with such conditions. On January 1, 2019, we adopted ASU 2018-07 and it did not have a material impact on the Company's Condensed Consolidated Financial Statements. In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which provides entities the option to reclassify tax effects stranded in accumulated other comprehensive income as a result of the 2017 Tax Cuts and Jobs Act (“the Tax Act”) to retained earnings. On January 1, 2019, we adopted ASU 2018-02 and it did not have a material impact on the Company's Condensed Consolidated Financial Statements. (g) Recently Issued Accounting Pronouncements In August 2018, the FASB issued ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General: Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. The objective of the guidance is to improve the effectiveness of disclosure requirements on defined benefit pension plans and other postretirement plans. The guidance is effective for fiscal years beginning after December 15, 2020. The Company does not expect adoption of the new standard to have a material impact on its Condensed Consolidated Financial Statements.

(a) The Company and Nature of Operations

FalconStor Software, Inc., a Delaware Corporation (the "Company" or "FalconStor"), is a leading storage software company offering a converged data services software platform that is hardware agnostic. The Company develops, manufactures and sells data migration, business continuity, disaster recovery, optimized backup and de-duplication solutions and provides the related maintenance, implementation and engineering services.

(b) Liquidity

As of March 31, 2019, we had a working capital deficiency of $2.5 million, which is inclusive of current deferred revenue of $6.2 million, and a stockholders' deficit of $12.0 million. During the three months ended March 31, 2019, we had a net loss of $0.1 million and negative cash flow from operations of $0.1 million. Our cash and cash equivalents at March 31, 2019 was $2.4 million, a decrease of $0.7 million as compared to December 31, 2018.

We believe that our cash flows from future operations and existing cash on hand are sufficient to conduct our planned operations and meet our contractual requirements for at least one year from the date of issuance of the accompanying consolidated financial statements.

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

(d) Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company’s significant estimates include those related to revenue recognition, accounts receivable allowances, share-based payment compensation, valuation of derivatives, capitalizable software development costs, valuation of goodwill and other intangible assets and income taxes. During the first quarter of 2018, the Company also had significant estimates in the determination of the fair value of Series A Preferred Stock, notes payable and warrants issued. Actual results could differ from those estimates.

The financial market volatility in many countries where the Company operates has impacted and may continue to impact the Company’s business. Such conditions could have a material impact on the Company’s significant accounting estimates discussed above.

(e) Unaudited Interim Financial Information

The accompanying unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations relating to interim financial statements.

In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary to present fairly the financial position of the Company at March 31, 2019, and the results of its operations for the three months ended March 31, 2019 and 2018. The results of operations of any interim period are not necessarily indicative of the results of operations to be expected for the full fiscal year. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes set forth in the Company's Annual Report on Form 10-K for the year ended December 31, 2018 ("2018 Form 10-K").

(f) Recently Adopted Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board (the "FASB") issued ASU No. 2016-02, which establishes a right-of-use (ROU) model that requires a lessee to record a right of use (ROU) asset and a lease liability on the balance sheet for most leases. In July 2018, the FASB issued ASU No. 2018-11, which amends the guidance to add a method of adoption whereby the issuer may elect to recognize a cumulative effect adjustment at the beginning of the period of adoption. ASU No. 2018-11 does not require comparative period financial information to be adjusted. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. ASU 2016-02 defines a lease as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment for a period of time in exchange for consideration. To determine whether a contract conveys the right to control the use of the identified asset for a period of time, the customer has to have both (1) the right to obtain substantially all of the economic benefits from the use of the identified asset and (2) the right to direct the use of the identified asset, a contract does not contain an identified asset if the supplier has a substantive right to substitute such asset ("the leasing criteria"). We have determined that our real estate leases with terms in excess of one year and which do not include an option to purchase the underlying asset, meet the leasing criteria. On January 1, 2019, we adopted ASU No. 2016-02, applying the package of practical expedients to leases that commenced before the effective date whereby we elected to not reassess the following: (i) whether any expired or existing contracts contain leases; (ii) the lease classification for any expired or existing leases; and (iii) initial direct costs for any existing leases. We elected to apply the transition provisions as of January 1, 2019, the date of adoption, and we recorded lease ROU assets of $2.9 million and related liabilities of $3.6 million million on our balance sheet related to our operating leases. We have no financing leases. There was no change to our consolidated statements of operations or cash flows.

In July 2018, the FASB issued ASU 2018-09, Codification Improvements. The amendments in ASU 2018-09 affect a wide variety of Topics in the FASB Codification and apply to all reporting entities within the scope of the affected accounting guidance. The Company has evaluated ASU 2018-09 in its entirety and determined that the amendments related to Topic 718-740, Compensation-Stock Compensation-Income Taxes, are the only provisions that currently apply to the Company. The amendments in ASU 2018-09 related to Topic 718-740, Compensation-Stock Compensation-Income Taxes, clarify that an entity should recognize excess tax benefits related to stock compensation transactions in the period in which the amount of the deduction is determined. On January 1, 2019, we adopted ASU 2018-09 and it did not have a material impact on the Company's 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, to expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees and supersedes the guidance in Subtopic 505-50, Equity - Equity-Based Payments to Non-Employees. Under ASU 2018-07, equity-classified nonemployee share-based payment awards are measured at the grant date fair value on the grant date. The probability of satisfying performance conditions must be considered for equity-classified nonemployee share-based payment awards with such conditions. On January 1, 2019, we adopted ASU 2018-07 and it did not have a material impact on the Company's Condensed Consolidated Financial Statements.

In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which provides entities the option to reclassify tax effects stranded in accumulated other comprehensive income as a result of the 2017 Tax Cuts and Jobs Act (“the Tax Act”) to retained earnings. On January 1, 2019, we adopted ASU 2018-02 and it did not have a material impact on the Company's Condensed Consolidated Financial Statements.

(g) Recently Issued Accounting Pronouncements

In August 2018, the FASB issued ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General: Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. The objective of the guidance is to improve the effectiveness of disclosure requirements on defined benefit pension plans and other postretirement plans. The guidance is effective for fiscal years beginning after December 15, 2020. The Company does not expect adoption of the new standard to have a material impact on its Condensed Consolidated Financial Statements.