Finite-Lived Intangible Assets, Net [Abstract] Schedule of intangible assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of future expected amortization of intangible assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance Employee Severance [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Restructuring costs Restructuring Costs Organization, Consolidation and Presentation of Financial Statements [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Machinio Machinio Corporation [Member] Machinio Corporation [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Reportable segments (in segments) Number of Reportable Segments Percentage of voting interest acquired Business Acquisition, Percentage of Voting Interests Acquired Cash consideration Payments to Acquire Businesses, Gross Equity consideration Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Contingent consideration Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High Segment Reporting [Abstract] Schedule of segment reporting information by segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Reconciliation of revenue from segments to consolidated Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Guarantees [Abstract] Guarantees Guarantees [Text Block] Future expected amortization of intangible assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2019 Remaining six months Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five 2024 and thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Intangible Assets, Net (Excluding Goodwill) Equity [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Options or stock appreciation rights Stock Options Or Stock Appreciation Rights [Member] Represents the stock options or stock appreciation rights. Other than options or stock appreciation rights Other Than Stock Options Or Stock Appreciation Rights [Member] Represents equity based awards other than stock options or stock appreciation rights. Employee and director options Employee And Non Employees Stock Option [Member] An arrangement whereby an employee or non-employee is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement. Although there are variations, normally, after vesting, when an option is exercised, the holder pays the strike value in cash to the issuing employer-entity and receives equity shares. The equity shares can be sold into the market for cash at the current market price without restriction. Options may be used to attract, retain and incentivize individuals, in addition to their regular compensation and benefits. Employee Stock Option Employee Stock Option [Member] Employee Stock Option - Market-Based Employee Stock Option - Market-Based [Member] Employee Stock Option - Market-Based [Member] Cash-settled stock appreciation rights Stock Appreciation Rights (SARs) [Member] Restricted Stock Restricted Stock [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Stockholders' Equity Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Shares available for issuance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Increase in shares available for issuance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Reserve shares counted per share granted from fungible share pool (in shares) Number Of Shares Counted For Grants Of Full Value Awards From Reserve Represents information pertaining to number of shares counted for grants of full-value awards from reserve which is established as fungible share pool. Number of shares awarded per person per year (in shares) Share Based Compensation Arrangement by Share Based Payment Award Number of Shares Awarded Per Person Per Year Represents the number of shares that can be awarded to any person under the stock based compensation plan per year. Shares and options vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Expected volatility, minimum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Expected volatility, maximum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Dividend yield (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Risk free interest rate, minimum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Risk free interest rate, maximum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Shares issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Granted (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Exercised Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number Shares repurchased (in shares) Treasury Stock, Shares, Acquired Amount yet to be expended under the program Stock Repurchase Program, Remaining Authorized Repurchase Amount Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] CAG CAG [Member] CAG [Member] GovDeals GovDeals [Member] GovDeals [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Goodwill Goodwill [Roll Forward] Balance at the beginning of the period Goodwill Business acquisition Goodwill, Acquired During Period Translation adjustments Goodwill, Foreign Currency Translation Gain (Loss) Balance at the end of the period Contractors [Abstract] Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Non-rolling stock Nonrolling Stock Surplus Contract [Member] Represents the non-rolling stock surplus contract entered into by the entity. Type of Arrangement and Non-arrangement Transactions [Axis] Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements and Non-arrangement Transactions [Domain] Arrangements and Non-arrangement Transactions [Domain] Scrap Contract Scrap Contract [Member] Represents the scrap contract entered into by the entity. Surplus Contract Surplus Contract [Member] Represents the surplus contract entered into by the entity. Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Government Contracts Concentration Risk Government Contracts Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Sales Revenue Sales Revenue, Net [Member] Significant Contracts Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] Number of contracts Number Of Contracts Number Of Contracts Term of contract Contract Term Represents the term of the contract, in PnYnMnDTnHnMnS format, for example, P1Y5M13D represents the reported fact of one year, five months, and thirteen days. Number of extensions Revenue From Contract With Customer, Number Of Contract Extensions Revenue From Contract With Customer, Number Of Contract Extensions Term of each renewal options extended Renewal Options Extended Term Represents the term of renewal options extended, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Adjusted percentage of profit sharing distribution Adjusted percentage of profit sharing distribution Represents the adjusted percentage of profits sharing distribution to the DLA Disposition Services by the entity. Concentration risk (as a percentage) Concentration Risk, Percentage Usable surplus property to be purchased as a fixed percentage of DoD's original acquisition value Usable Surplus Property to be Purchased as Percentage of Original Acquisition Value Represents the fixed percentage of DoD's original acquisition value at which the entity is required to purchase all usable surplus property offered to it by the Department of Defense. Schedule of stockholders equity Schedule of Stockholders Equity [Table Text Block] Summary of stock options and restricted stock granted Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Subsequent Events Subsequent Events [Text Block] Income Tax Disclosure [Abstract] Blended effective tax rate (as a percentage) Tax Cuts and Jobs Act of 2017, Blended Tax Rate, Percent Tax Cuts and Jobs Act of 2017, Blended Tax Rate, Percent Tax benefit relating to adjustment in corporate tax rate Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Deferred Tax Asset, Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Deferred Tax Asset, Income Tax Expense (Benefit) Expected effective tax rate (as a percent) Estimated Effective Income Tax Rate Continuing Operations Represents the estimated effective tax rate for the current fiscal year. Retirement Benefits [Abstract] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Settlement cost Defined Benefit Plan, Settlement Cost Defined Benefit Plan, Settlement Cost Total net periodic (benefit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Fair Value Disclosures [Abstract] Fair Value Measurement Fair Value Disclosures [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Certificates of deposits Certificates of Deposit, at Carrying Value Interest rate Short-Term Investments, Interest Rate Short-Term Investments, Interest Rate Commitments and Contingencies Disclosure [Abstract] Legal Proceedings Legal Matters and Contingencies [Text Block] Accounting Policies [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Remaining performance obligation Revenue, Remaining Performance Obligation Remaining performance obligation, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Restructuring and Related Activities [Abstract] Business Realignment Expenses Restructuring and Related Activities Disclosure [Text Block] Changes in financial assets fair value Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Contract intangibles Contractual Rights [Member] Technology Brand Assets And Developed Technology Rights [Member] Represents information pertaining to brand assets and developed technology rights. Patent and trademarks Patents And Trademarks [Member] Represents rights acquired through registration of a trademark to gain or protect exclusive use of a business name, symbol or other device or style and exclusive legal right granted by the government to the owner of the patent to exploit an invention or a process for a period of time specified by law. Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Useful Life (in years) Finite-Lived Intangible Asset, Useful Life Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Goodwill Goodwill Disclosure [Text Block] Stockholders' Equity Shareholders' Equity and Share-based Payments [Text Block] Revenue Product [Member] Fee revenue Service Fee [Member] Service Fee [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Corporate & Other Corporate, Non-Segment [Member] RSCG RSCG [Member] RSCG [Member] Total revenue Revenue from Contract with Customer, Excluding Assessed Tax Gross profit Gross Profit Operating expenses Operating Expenses Other operating expenses Other Operating Income (Expense), Net Interest and other income, net Interest Income (Expense), Net Provision (benefit) for income taxes Income Tax Expense (Benefit) Net loss Net Income (Loss) Available to Common Stockholders, Basic Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Accumulated Deficit Retained Earnings [Member] Statement Statement [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance (in shares) Shares, Issued Balance Stockholders' Equity Attributable to Parent Cumulative adjustment related to adoption of ASC 606 Cumulative Effect of New Accounting Principle in Period of Adoption Net loss Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units (in shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Compensation expense from grants of common stock options and restricted stock Adjustment To Additional Paid In Capital Share-Based Compensation Requisite Service Period Recognition Value And Income Tax Effect From Share Based Compensation Net Represents the aggregate of (i) the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation"; and (ii) adjustment to additional paid in capital related to the net effect of excess tax benefits and tax deficiencies associated with an equity-based compensation plan other than an employee stock ownership plan (ESOP). Foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Forfeiture of restricted stock awards (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Foreign currency translation and other Other Comprehensive Income (Loss), Foreign Currency Transaction And Translation Adjustment And Other, Net Of Tax, Portion Attributable To Parent Other Comprehensive Income (Loss), Foreign Currency Transaction And Translation Adjustment And Other, Net Of Tax, Portion Attributable To Parent Balance (in shares) Balance Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASC 606 Accounting Standards Update 2014-09 [Member] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Balance without adoption of ASC 606 Calculated under Revenue Guidance in Effect before Topic 606 [Member] Effect of change Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Consolidated statement of operations: Income Statement [Abstract] Consolidated balance sheet: Statement of Financial Position [Abstract] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Other assets Other Assets, Noncurrent Accumulated deficit Retained Earnings (Accumulated Deficit) Defined Benefit Pension Plan Pension and Other Postretirement Benefits Disclosure [Text Block] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] IronDirect IronDirect [Member] IronDirect [Member] Occupancy Cost Occupancy Cost [Member] Occupancy Cost [Member] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] Severance Agreement Severance Agreement [Member] Severance Agreement [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] District of Columbia DISTRICT OF COLUMBIA Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Operating Expense Other Operating Income (Expense) [Member] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Real Estate [Domain] Real Estate [Domain] Office Building Office Building [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring reserve Restructuring Reserve Restructuring charges Restructuring Charges Loss on contract termination Loss on Contract Termination Payment on contract loss termination Increase (Decrease) Loss On Contract Termination Increase (Decrease) Loss On Contract Termination Schedule of Revenue by Major Customers, by Reporting Segments [Table] Schedule of Revenue by Major Customers, by Reporting Segments [Table] Non-US Non-US [Member] Geographic Concentration Risk Geographic Concentration Risk [Member] Revenue, Major Customer [Line Items] Revenue, Major Customer [Line Items] Segments percentage of revenue (as a percentage) Reportable Segments Percentage of Revenue Reportable Segments Percentage of Revenue Concentration risk (as a percentage) Organization Nature of Operations [Text Block] Schedule of net periodic benefit cost recognized Schedule of Net Benefit Costs [Table Text Block] Statement of Cash Flows [Abstract] Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash (used in) provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock compensation expense Share-based Compensation Provision for inventory allowance Inventory Write-down Provision for doubtful accounts Provision for Doubtful Accounts Deferred tax provision (benefit) Deferred Income Tax Expense (Benefit) Gain on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Change in fair value of financial instruments Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Change in fair value of earnout liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Inventory Increase (Decrease) in Inventories Prepaid and deferred taxes Increase (Decrease) In Prepaid Expenses And Deferred Taxes Represents the combined amount of increase (decrease) of consideration paid in advance for income and other taxes that provide economic benefits in future periods and deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued expenses and other current liabilities Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Distributions payable Increase (Decrease) in Profit Sharing Distributions Payable The Net change in disbursement made as per the profit sharing arrangements after deducting the allowable operating expenses. Deferred revenue Increase (Decrease) In Contract With Customer, Liability Increase (Decrease) In Contract With Customer, Liability Payables to sellers Increase (Decrease) In Payables To Sellers The net change during the reporting period in the amount of cash held on behalf of the sellers in the case of consignment sales transactions. Other liabilities Increase (Decrease) in Other Operating Liabilities Net cash (used in) provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Increase in intangibles Increase (Decrease) in Intangible Assets, Current Purchases of property and equipment, including capitalized software Payments to Acquire Property, Plant, and Equipment Proceeds from sales of property and equipment Proceeds from Sale of Property, Plant, and Equipment Maturities of short-term investments Payments to Acquire Short-term Investments Maturities of short-term investments Proceeds from Sale, Maturity and Collection of Short-term Investments Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Proceeds from exercise of common stock options (net of tax) Proceeds from Stock Options Exercised Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate differences on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net (decrease) increase in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of period Supplemental disclosure of cash flow information Supplemental Cash Flow Information [Abstract] Cash paid for income taxes, net Income Taxes Paid, Net Intangible Assets Intangible Assets Disclosure [Text Block] Guarantee obligation value, maximum Guarantor Obligations, Current Carrying Value Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring basis Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Assets Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance, contingent consideration Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Change in fair value Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Ending balance, contingent consideration Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance, financial instruments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Change in fair value Ending balance, financial instruments Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Employee severance and benefit costs Occupancy and other costs Occupancy And Other Costs [Member] Occupancy And Other Costs [Member] Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Beginning balance Business Realignment Expenses Cash Payments Payments for Restructuring Ending balance Significant Contracts Long-term Contracts or Programs Disclosure [Text Block] Accounting Standards Update 2017-07 Accounting Standards Update 2017-07 [Member] Accounting Standards Update 2017-07 [Member] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Domain] Capitalized Contract Cost [Domain] Prepaid Expenses and Other Current Assets Prepaid Expenses and Other Current Assets [Member] Schedule of Receivables with Imputed Interest, Name of Receivable with Imputed Interest [Axis] Schedule of Receivables with Imputed Interest, Name of Receivable with Imputed Interest [Axis] Name of Receivable with Imputed Interest [Domain] Name of Receivable with Imputed Interest [Domain] Tanager Acquisitions Promissory Note Tanager Acquisitions Promissory Note [Member] Tanager Acquisitions Promissory Note [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets Other Assets [Member] Supplier Concentration Risk Supplier Concentration Risk [Member] Cost of Goods Cost of Goods, Total [Member] Contract With Commercial Client Contract With Commercial Client [Member] Represents the information pertaining to the contract with commercial client. Contract asset Contract with Customer, Asset, Net Contract costs Capitalized Contract Cost, Net Receivable with imputed interest, face amount Receivable with Imputed Interest, Face Amount Receivable with imputed interest, term Receivable With Imputed Interest, Term Receivable with Imputed Interest, Term Proceeds from collection of notes receivable Proceeds from Collection of Notes Receivable Receivable with imputed interest, net amount Receivable with Imputed Interest, Net Amount Decrease in general and administrative expense from reclassification General and Administrative Expense Increase in interest and other income, net Unaudited Interim Financial Information Basis of Accounting, Policy [Policy Text Block] Revenue Recognition Revenue From Contract With Customer [Policy Text Block] Revenue From Contract With Customer [Policy Text Block] Promissory Note Receivables, Policy [Policy Text Block] Risk Associated with Certain Concentrations Concentration Risk, Credit Risk, Policy [Policy Text Block] Earnings per Share Earnings Per Share, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Employee Stock Option - Time Based Employee Stock Option - Time Based [Member] Employee Stock Option - Time Based [Member] Employee Stock Option - Market-Based and Performance-Based Employee Stock Option - Market And Performance Based [Member] Employee Stock Option - Market And Performance Based [Member] Restricted Stock - Time Based Restricted Stock - Time Based [Member] Restricted Stock - Time Based [Member] Restricted Stock - Market Based and Performance-Based Restricted Stock - Market And Performance Based [Member] Restricted Stock - Market And Performance Based [Member] Stock options: Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures [Abstract] Options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Options granted (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Restricted stock: Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Restricted shares granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Document and Entity Information Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Summary of goodwill activity Schedule of Goodwill [Table Text Block] Amortization of intangible assets Amortization of Intangible Assets Restructuring and related costs Restructuring and Related Costs [Table Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Accounts receivable, net of allowance for doubtful accounts of $300 and $337 at March 31, 2019 and September 30, 2018, respectively Accounts Receivable, Net, Current Inventory, net Inventory, Net Prepaid taxes and tax refund receivable Prepaid Taxes Total current assets Assets, Current Property and equipment, net of accumulated depreciation of $12,447 and $11,078 at March 31, 2019 and September 30, 2018, respectively Property, Plant and Equipment, Net Intangible assets, net Goodwill Deferred tax assets Deferred Income Tax Assets, Net Total assets Assets Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued expenses and other current liabilities Accrued Expenses and Other Current Liabilities Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent, utilities, PTO and accrued bonuses and commissions. It also includes aggregate carrying amount, as of the balance sheet date, of current obligations not separately disclosed in the balance sheet due to materiality considerations. Current liabilities are expected to be paid within one year (or the normal operating cycle, if longer). Distributions payable Profit Sharing Distributions Payable This element represents the current portion of the profit sharing distributions payable. Deferred revenue Contract with Customer, Liability, Current Payables to sellers Payables To Sellers, Current Payables to Sellers, Current Total current liabilities Liabilities, Current Deferred taxes and other long-term liabilities Deferred Income Taxes and Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 12) Commitments and Contingencies Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $0.001 par value; 120,000,000 shares authorized; 33,347,657 shares issued and outstanding at March 31, 2019; 32,774,118 shares issued and outstanding at September 30, 2018 Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Total liabilities and stockholders’ equity Liabilities and Equity Impact of adoption of ASC 606 Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class of Stock [Line Items] Class of Stock [Line Items] Cumulative adjustment related to adoption of ASU 2016-09 Net loss Exercise of common stock options and vesting of restricted stock (in shares) Exercise of common stock options and vesting of restricted stock Compensation expense and incremental tax benefit from grants of common stock options and restricted stock Foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction And Translation Adjustment, Net Of Tax, Portion Attributable To Parent (Including Impact To Retained Earnings) Other Comprehensive Income (Loss), Foreign Currency Transaction And Translation Adjustment, Net Of Tax, Portion Attributable To Parent (Including Impact To Retained Earnings) Accounts receivable, allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Property and equipment, accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Segment Information Segment Reporting Disclosure [Text Block] Statement [Line Items] Costs and expenses from operations: Costs and Expenses [Abstract] Cost of goods sold (exclusive of depreciation and amortization) Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization Seller distributions Production and Distribution Costs Technology and operations Technology And Operations Expense Includes technology expenses which consist primarily of personnel costs related to programming staff who develop and deploy new marketplaces and continuously enhance existing marketplaces. These personnel also develop and upgrade the software systems that support operations, such as sales processing. It also includes operations expenses which consist primarily of operating costs, including buyer relations, shipping logistics and distribution center operating costs. Sales and marketing Selling and Marketing Expense General and administrative Other operating expenses Total costs and expenses Costs and Expenses Loss from operations Operating Income (Loss) Loss before provision (benefit) for income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Basic and diluted loss per common share (in dollars per share) Earnings Per Share, Basic and Diluted Basic and diluted weighted average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic and Diluted