Document and Entity Information [Abstract] Statement [Table] Class of Stock [Axis] Class of Stock [Domain] Common Class A [Member] Common Class A [Member] Class A Common Stock Class B Common Stock [Member] Common Class B [Member] Class B Common Stock Class B Common Stock [Member] Statement [Line Items] Entity Registrant Name Entity Central Index Key Amendment Flag Current Fiscal Year End Date Document Type Trading Symbol Trading Symbol Document Period End Date Document Fiscal Period Focus Document Fiscal Year Focus Entity Filer Category Entity Common Stock, Shares Outstanding Balance Sheets [Abstract] Common Stock To Be Issued [Member] To Be Issued Common stock to be issued Represent information of common stock to be issued. Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and cash equivalents at beginning of period Cash and cash equivalents Cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Accounts Receivable, Net, Current Trade accounts receivable, net of allowance for doubtful accounts of $0 and $0, respectively Prepaid Expense, Current Prepaid expenses and other current assets Assets, Current Total current assets Intangible Assets, Net (Excluding Goodwill) Intangible assets Other Assets, Noncurrent Other assets Assets Total assets: Total Assets Liabilities and Equity [Abstract] Liabilities and Equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Trade, Current Trade accounts payable Accrued Liabilities, Current Prepaid expenses Accrued expenses TOTAL Deferred Revenue, Current Deferred revenue Taxes Payable, Current Income taxes payable Liabilities, Current Total current liabilities Deferred Revenue, Noncurrent Deferred revenue - long-term portion Liabilities TOTAL LIABILITIES Total liabilities Commitments and Contingencies Commitments and contingencies Equity [Abstract] Equity Stockholders' Equity Attributable to Parent [Abstract] Straight Path Communications Inc. stockholders' equity: Preferred Stock, Value, Issued Preferred stock, $0.01 par value; 3,000 shares authorized; no shares issued and outstanding Common Stock, Value, Issued Common stock value Additional Paid in Capital Additional paid-in capital Retained Earnings (Accumulated Deficit) Accumulated deficit Accumulated deficit Treasury Stock, Value Treasury stock, value Number of shares held in treasury stock, value Treasury stock, 40 shares at cost Stockholders' Equity Attributable to Parent Total Straight Path Communications Inc. stockholders' equity Stockholders' Equity Attributable to Noncontrolling Interest Noncontrolling interests Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total equity Balance Balance Liabilities and Equity Liabilities and equity Total liabilities and equity Beginning balance Ending Balance Equity Components [Axis] Equity Component [Domain] Common Stock Common Stock [Member] Common Stock Allowance for Doubtful Accounts Receivable Net of allowance for doubtful accounts Allowance for doubtful accounts, Balance at beginning of year Allowance for doubtful accounts, Balance at end of year Preferred Stock, Par or Stated Value Per Share Preferred stock, par value Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred stock, shares issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Common Stock, Par or Stated Value Per Share Common stock, par value Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock shares distributed Common stock, shares issued Common Stock, Shares, Outstanding Common stock, shares outstanding Common stock, shares outstanding Balance (in shares) Balance (in shares) Treasury Stock, Shares Treasury stock, shares Statements of Operations [Abstract] Revenues Revenues Revenues Costs and Expenses [Abstract] Costs and expenses: Cost of Revenue Direct cost of revenues Research and Development Expense Research and development Research and development expenses Selling, General and Administrative Expense Included in Selling, general and administrative expenses Selling, general and administrative Costs and Expenses Total costs and expenses Operating Income (Loss) (Loss) income from operations Loss from operations Income (loss) from operations Loss from operations Other Income and Expenses [Abstract] Other income: Interest Income, Other Interest income Other Income Other income Interest and Other Income Total other income Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income (loss) before income taxes Loss before income taxes Income Tax Expense (Benefit) Provision for income taxes PROVISION FOR INCOME TAXES Provision for income taxes Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net loss Net loss Net loss Income (Loss) Attributable to Noncontrolling Interest Net loss attributable to noncontrolling interests Net loss attributable to noncontrolling interests Net Income (Loss) Attributable to Parent Net loss Net (loss) income Net loss attributable to Straight Path Communications Inc. Earnings (loss) per share attributable to Straight Path Communications Inc. stockholders: Loss per share attributable to Straight Path Communications Inc. stockholders: Earnings Per Share, Basic and Diluted Basic and diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted-average number of shares used in calculation of loss per share: Weighted Average Number of Shares Outstanding, Basic and Diluted Basic and diluted Statement of Stockholders' Equity [Abstract] Additional Paid-in Capital [Member] Additional Paid-In Capital Retained Earnings [Member] Accumulated Deficit Treasury Stock [Member] Treasury Stock Noncontrolling Interest [Member] Noncontrolling Interests Shares, Outstanding Common stock, shares outstanding Common stock, Shares outstanding Balance (in shares) Balance (in shares) Stock Issued During Period, Value, Share-based Compensation, Gross Common stock issued for compensation Common stock issued for compensation Common stock issued or to be issued for compensation Stock Issued During Period, Shares, Share-based Compensation, Gross Common stock issued for compensation (in shares) Stock issued during period as compensation, Shares Stock issued during period as compensation Stock issued during period as compensation, Shares Stock Issued During Period, Value, Share-based Compensation, Forfeited Stock-based compensation is included in selling, general and administrative Stock-based compensation Statement of Cash Flows [Abstract] Net Cash Provided by (Used in) Operating Activities [Abstract] Operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Allocated Share-based Compensation Expense Common stock issued for compensation Share-based Compensation Common stock issued for compensation Stock-based compensation Stock-based compensation is included in selling, general and administrative Common stock issued or to be issued for compensation Increase (Decrease) in Operating Capital [Abstract] Changes in assets and liabilities: Increase (Decrease) in Accounts Receivable Trade accounts receivable, net Trade accounts receivable, net Increase (Decrease) in Prepaid Expense Prepaid expenses - settlements Prepaid expenses - related to settlements and licensing Increase (Decrease) in Prepaid Expenses, Other Prepaid expenses and other current assets Increase Decrease In Prepaid Expenses Development Agreement Prepaid expenses - development agreement Prepaid expenses - development agreement Represent amount of Prepaid expenses development agreement. Prepaid expenses - development agreement Increase (Decrease) in Other Operating Assets, Total Other assets Other assets Increase (Decrease) in Accounts Payable, Trade Trade accounts payable Increase (Decrease) in Accrued Liabilities Accrued expenses Increase (Decrease) in Deferred Revenue Deferred revenue Increase (Decrease) in Income Taxes Payable Income taxes payable Income taxes payable Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash used in operating activities Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents Supplemental cash flow information [Abstract] Supplemental cash flow information Income Taxes Paid, Net Cash paid during the period for income taxes Purchase of intangibles Basis of Presentation [Abstract] Basis of Presentation [Abstract] Basis of Accounting [Text Block] Basis of Presentation Basis of Presentation Summary of Significant Accounting Policies and Recent Pronouncements [Abstract] Basis of Presentation [Abstract] Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies and Recent Pronouncements Fair Value Measures [Abstract] Fair Value Disclosures [Text Block] Fair Value Measures Stockholders' Equity Note Disclosure [Text Block] Equity Stock-Based Compensation [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-Based Compensation (Loss) Earnings Per Share [Abstract] (Loss) earnings per share attributable to Straight Path Communications Inc. stockholders: Earnings Per Share [Text Block] (Loss) Earnings Per Share Related Party Transactions [Abstract] Related Party Transactions [Abstract] Related Party Transactions Disclosure [Text Block] Related Party Transactions Concentration of Customers [Abstract] Concentration Risk Disclosure [Text Block] Concentration of Customers Income Taxes [Abstract] Income Tax Disclosure [Text Block] Income Taxes Business Segment Information [Abstract] Business Segment Information Segment Reporting Disclosure [Text Block] Business Segment Information Commitments and Contingencies [Abstract] Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies New Accounting Pronouncements, Policy [Policy Text Block] Summary of Significant Accounting Policies and Recent Pronouncements Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Summary of shares excluded from the diluted earnings per share computations Schedule of Weighted Average Number of Shares [Table Text Block] Schedule of the exercise price was greater than the average market price of the Class B common shares Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block] Schedule of revenues from transactions with single customer Schedule of Segment Reporting Information, by Segment [Table Text Block] Summary of operating results for the business segments Reconciliation of Assets from Segment to Consolidated [Table Text Block] Summary of total assets for the business segments Schedule of Subsidiary of Limited Liability Company or Limited Partnership [Table] Legal Entity [Axis] Entity [Domain] Subsidiaries [Member] Straight Path Spectrum [Member] Straight Path [Member] Subsidiaries One Member Straight Path IP Group [Member] Straight Path IP Group [Member] Subsidiaries One. Subsidiary of Limited Liability Company or Limited Partnership [Line Items] Basis of Presentation (Textual) Basis Of Presentation Textual [Abstract] Basis of Presentation (Textual) Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions Ownership in straight path spectrum Schedule of Stock by Class [Table] Title of Individual [Axis] Relationship to Entity [Domain] Officer [Member] Officers [Member] Employee [Member] Other Employees [Member] Represents employee. Chief Executive Officer [Member] Davidi Jonas [Member] Consultant [Member] Consultant [Member] Director [Member] Directors [Member] Treasury Stock, Common [Member] Treasury Stock, Common [Member] Class of Stock [Line Items] Equity (Textual) Equity Textual [Abstract] Equity (Textual) Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Officers And Employees [Member] Officers and Employees [Member] Officers and employees. Jonas [Member] Range [Axis] Range [Domain] Minimum [Member] Minimum [Member] Maximum Maximum [Member] Vesting [Axis] Vesting [Domain] Vested One [Member] Vested One [Member]. Vested Two [Member] Vested Two [Member]. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Stock-Based Compensation Textual [Abstract] Stock-Based Compensation (Textual) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Class B common stock reserved for grant of awards under 2013 Plan Stock Issued During Period, Shares, Restricted Stock Award, Gross Granted restricted shares of Class B common stock Stock Issued During Period, Value, Restricted Stock Award, Gross Fair value of granted restricted shares of Class B common stock Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Vesting period Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Unrecognized compensation cost related to non-vested restricted shares Expected To Recognize Unrecognized Compensation Cost Next Fiscal Year Unrecognized compensation cost 2017 Represents expected amount to recognize the unrecognized compensation cost for next fiscal year. Expected To Recognize Unrecognized Compensation Cost Fiscal Year Two Unrecognized compensation cost 2018 Represents expected amount to recognize the unrecognized compensation cost for fiscal year two. Expected To Recognize Unrecognized Compensation Cost Fiscal Year Three Unrecognized compensation cost 2019 Represents expected amount to recognize the unrecognized compensation cost for fiscal year three. Expected To Recognize Unrecognized Compensation Cost Fiscal Year Four Unrecognized compensation cost 2020 Represents expected amount to recognize the unrecognized compensation cost for fiscal year four. Expected To Recognize Unrecognized Compensation Cost Fiscal Year Five Unrecognized compensation cost 2021 Represents expected amount to recognize the unrecognized compensation cost for fiscal year five. Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Domain] Employee Stock Option [Member] Stock options [Member] Shares underlying stock options [Member] Non Vested Restricted Class B Common Stock [Member] Non-vested restricted Class B common stock [Member] Earnings Per Share, Diluted, Other Disclosures [Abstract] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Shares excluded from the calculation of diluted earnings (loss) per share Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Stock options Concentration Risk [Table] Customer [Axis] Customer [Domain] Customer One [Member] Customer 1 [Member] Customer One. Customer Two [Member] Customer 2 [Member] Customer two. Customer Three [Member] Customer 3 [Member] Customer Three. Customer Four [Member] Customer 4 [Member] Customer four. Concentration Risk [Line Items] Sales Revenue, Goods, Net Revenue Schedule of Product Information [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Sales Revenue, Net [Member] Straight Path Spectrum's revenues [Member] Product Information [Line Items] Concentration Of Customers Textual [Abstract] Concentration of Customers (Textual) Concentration Risk, Percentage Concentration risk percentage Schedule of Segment Reporting Information, by Segment [Table] Subsidiaries Two [Member] Straight Path Ventures [Member] Subsidiaries two. Segment Reporting Information [Line Items] Segment Reporting Information, Profit (Loss) [Abstract] Summary of operating results for the business segments Segment Reporting Information, Additional Information [Abstract] Summary of total assets for the business segments Business Segment Information Textual [Abstract] Business Segment Information (Textual) Number of Reportable Segments Reportable Segments Percentage Of General And Administrative Expenses Percentage of general and administrative expenses The percentage of general and administrative expenses. Percentage Of Employment Expenses Employment expenses of Chief Technology Officer The percentage of employment expenses. Employee Expenses Related To Another Employee Employee expenses related to another employee The percentage of employee expenses. Product Liability Contingency [Table] Former Chief Executive Officer [Member] Former Chief Executive Officer [Member] Former Chief Executive Officer [Member] Product Liability Contingency [Line Items] Commitments and Contingencies (Textual) Commitments And Contingencies Textual [Abstract] Commitments and Contingencies (Textual) Percentage Of Amount Recovered From Patent Infringers Paid To Law Firm Recoverable contingency patents allegedly infringed, percentage Recoverable contingency patents allegedly infringed, percentage Percentage of amount recovered from patent infringers paid to law firms. Amount Recovered From Patent Infringers Paid To Law Firm Terms Settlement of litigation, description Settlement of litigation, description Amount recovered from patent infringers paid to law firms terms. Payments From Future Revenue From Spectrum Percentage Payments to be made from revenue, percentage Payments From Future Revenue From Spectrum Percentage Payments from future revenues from spectrum, Percentage. Maximum Future Payment For Wireless Spectrum Licenses Amount of maximum future payment for wireless spectrum licenses Amount of maximum future payment for wireless spectrum licenses Maximum future payment for wireless spectrum licenses. Cumulative Amount Paid For Payment From Future Revenues From Spectrum Obligation Amount incurred for obligation Cumulative amount paid for payment from future revenues from spectrum obligation.