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 Class B [Member] Common Class B [Member] Class B 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 - related to IP settlements and licensing Other Assets, Current Other current assets Assets, Current Total current assets Prepaid Expense, Noncurrent Prepaid expenses - development agreement Property, Plant and Equipment, Net Property and equipment, net of accumulated depreciation 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 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 Class A common stock, $0.01 par value; 2,000 shares authorized; 787 shares issued and outstanding Additional Paid in Capital Additional paid-in capital Retained Earnings (Accumulated Deficit) (Accumulated deficit) retained earnings Accumulated deficit Treasury Stock, Value Number of shares held in treasury stock, value Treasury stock, 42 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 [Member] Common Stock [Member] Common Stock Allowance for Doubtful Accounts Receivable Net of allowance for doubtful accounts (in dollars) 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 (in dollars per share) 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 (in dollars per share) 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] Revenue, Net, Total Revenues Revenues Revenues Included in Direct cost of revenues Costs and Expenses [Abstract] Costs and expenses: Cost of Goods and Services Sold, Total Included in Direct cost of revenues 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 (Loss) income from operations Nonoperating Income (Expense) [Abstract] Other income: Investment Income, Interest Interest income Other Nonoperating Income Other income Nonoperating Income (Expense), Total Total other income Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income (loss) before income taxes (Loss) income 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) income Net (loss) income Income (Loss) Attributable to Noncontrolling Interest Net loss attributable to noncontrolling interests Net loss (income) attributable to noncontrolling interests Net Income (Loss) Attributable to Parent Net loss Net (loss) income Net (loss) income attributable to Straight Path Communications Inc. Earnings (loss) per share attributable to Straight Path Communications Inc. stockholders: (Loss) earnings per share attributable to Straight Path Communications Inc. stockholders: Earnings Per Share, Basic Basic Earnings Per Share, Diluted Diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted-average number of shares used in calculation of (loss) earnings per share: Weighted Average Number of Shares Outstanding, Basic Basic weighted-average number of shares Basic Weighted Average Number of Shares Outstanding, Diluted Diluted weighted-average number of shares Diluted Diluted weighted-average number of shares Statement of Stockholders' Equity [Abstract] Additional Paid-in Capital [Member] Additional Paid-In Capital Retained Earnings [Member] (Accumulated Deficit) Retained Earnings Treasury Stock [Member] Treasury Stock Noncontrolling Interest [Member] Noncontrolling Interests Shares, Outstanding, Beginning Balance 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 or to be 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, Value, Stock Options Exercised Common stock issued for exercises of stock options Statement of Cash Flows [Abstract] Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net (loss) income to net cash used in operating activities: Share-based Compensation, Total Common stock issued for compensation Common stock issued or to be issued for compensation Common stock issued or to be issued for compensation Deferred Income Tax Expense (Benefit) Deferred tax assets Deferred tax assets Deferred tax assets 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 IP settlements and licensing Increase (Decrease) in Other Current Assets Other current assets 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 Due to Related Parties Due to IDT Corporation 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 Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Investing activities: Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment Purchases of property and equipment Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash used in investing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Financing activities: Proceeds from Stock Options Exercised Common stock issued upon exercise of stock options Common stock issued for exercises of stock options Common stock issued upon exercise of stock options Proceeds from Sale of Treasury Stock Sale of treasury stock Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental schedule of noncash activities Common Stock Withheld For Tax Purposes Common stock withheld for payroll tax purposes Common stock repurchased for withholding tax purposes Common stock withheld for tax purposes. Common stock withheld for payroll tax purposes Supplemental cash flow information [Abstract] Supplemental cash flow information Income Taxes Paid, Net Cash paid during the period for income taxes 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 Stockholders' Equity Note Disclosure [Text Block] Equity (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 Weighted Average Number of Shares [Table Text Block] Summary of components of the earnings (loss) per common share calculation 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 Related Party Transactions [Table Text Block] Schedule of expenses incurred on related party transactions 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] Subsidiaries One Member Straight Path IP [Member] Straight Path IP Group [Member] Subsidiaries One. Idt [Member] IDT [Member] IDT [Member] 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] Chief Executive Officer [Member] Davidi Jonas [Member] Employee [Member] Employee [Member] Represents employee. Director [Member] Directors [Member] Consultant [Member] Award Type [Axis] Equity Award [Domain] Restricted Stock [Member] Restricted Shares [Member] Sixteen March Two Thousand Sixteen [Member] March 16, 2016 [Member] Sixteen march two thousand sixteen. Thirteen June Two Thousand Sixteen [Member] June 13, 2016 [Member] Thirteen June two thousand sixteen. Seventeen October Two Thousand Sixteen [Member] October 17, 2016 [Member] Seventeen october two thousand sixteen. Plan Name [Axis] Plan Name [Domain] Stock Option And Incentive 2013 Plan [Member] 2013 Plan [Member] Name of the equity-based compensation arrangement plan. Class of Stock [Line Items] Equity (Textual) Equity Textual [Abstract] Equity (Textual) Number of shares held in treasury stock, shares Number of shares held in treasury stock, shares Treasury Stock, Value, Acquired, Cost Method Number of shares held in treasury stock, value Treasury stock, 42 shares at cost Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Class B common stock available for the grant of awards Stock Issued During Period, Shares, Issued for Services Stock issued during period, Shares Stock Issued During Period, Shares, Issued for Services Stock Issued During Period, Value, Issued for Services Stock issued during period, Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Restricted shares, granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Restricted shares, Vested Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Number of restricted shares issued, value Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights Description of restricted shares vesting condition Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights Allocated Share-based Compensation Expense Stock-based compensation expense 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 Fiscal Year Current 2016 Represents expected amount to recognize the unrecognized compensation cost for current fiscal year. Expected To Recognize Unrecognized Compensation Cost Next Fiscal Year 2017 Represents expected amount to recognize the unrecognized compensation cost for next fiscal year. Expected To Recognize Unrecognized Compensation Cost Fiscal Year Two 2018 Represents expected amount to recognize the unrecognized compensation cost for fiscal year two. Expected To Recognize Unrecognized Compensation Cost Fiscal Year Three 2019 Represents expected amount to recognize the unrecognized compensation cost for fiscal year three. Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Basic and Diluted weighted-average number of shares [Abstract] Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Effect of dilutive securities: Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Shares underlying stock options Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends Non-vested restricted Class B common stock Non Vested Restricted Class B Common Stock [Member] Non-vested restricted Class B common stock [Member] Non-vested restricted Class B common stock. 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] 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 Schedule of Related Party Transactions, by Related Party [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Transmission Service Agreement [Member] Transition Service Agreement [Member] Related Party Transaction [Axis] Related Party Transaction [Domain] International Discount Telecommunications [Member] IDT [Member] International discount telecommunications. Related Party Transaction [Line Items] Related Party Transactions (Textual) Related Party Transaction, Due from (to) Related Party [Abstract] Related Party Transaction, Due from (to) Related Party [Abstract] Related Party Transaction, Expenses from Transactions with Related Party Regulatory fees Included in direct cost of revenues Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Included in selling, general and administrative Payroll, benefits, insurance, facilities and other expenses Related Party [Axis] Related Party [Domain] Related Party Transactions Textual [Abstract] Related Party Transactions (Textual) Income From Payments Of Liabilities Income from IDT Corporation payments of liabilities Income from payments of liabilities. Legal Fees legal expenses 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. Sales Revenue, Goods, Net Revenue Schedule of Product Information [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Sales Revenue, Net [Member] Sales Revenue Net [Member] Product Information [Line Items] Concentration Of Customers Textual [Abstract] Concentration of Customers (Textual) Concentration Risk, Percentage Concentration risk percentage Income Taxes Textual [Abstract] Income Taxes (Textual) Deferred Income Tax Assets Valuation Allowance Percentage Deferred income tax assets valuation allowance percentage Deferred income tax assets valuation allowance percentage. Schedule of Segment Reporting Information, by Segment [Table] 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 Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event [Member] 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. Product Liability Contingency [Table] Former Chief Executive Officer [Member] Former Chief Executive Officer [Member] Former Chief Executive Officer [Member] Range [Axis] Range [Domain] Minimum [Member] Minimum [Member] Maximum Maximum [Member] Economic Area License [Member] 39 GHz Economic Area [Member] Economic area license. Local Multipoint Distribution Service License [Member] LMDS 28 GHz range [Member] Other Commitments [Axis] Other Commitments [Domain] Licenses Expire On Two Thousand Eighteen August Ten [Member] Licenses expire on august 10, 2018 [Member] Licenses Expire On Two Thousand Eighteen September Twenty One [Member] Licenses expire on September 21,2018 [Member] Geographical [Axis] Geographical [Domain] NEW YORK NEW YORK [Member] Product Liability Contingency [Line Items] Commitments and Contingencies (Textual) Commitments And Contingencies Textual [Abstract] Commitments and Contingencies (Textual) Loss Contingency, Patents Allegedly Infringed, Number Infringe of patents Percentage Of Amount Recovered From Patent Infringers Paid To Law Firm 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 Amount recovered from patent infringers paid to law firms terms. Loss Contingency, Damages Sought, Value Compensatory damages Litigation Settlement Collateral Amount Arbitration proceedings, collateral Litigation settlement collateral amount. Prepaid Expense Fee Prepaid expense fee Represents prepaid expense fee. Prepaid Expense Prepaid expenses Lease Expiration Date Lease expiration date Operating Leases, Rent Expense, Net Annual rent Licenses To Be Expired Licenses to be expired Number of licenses to be expired. 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. Option To Purchase Percentage Of Outstanding Shares Percentage Outstanding common stock of Straight Path IP Percentage Stock option purchase of consultant, percentage Option to purchase percentage of outstanding shares percentage during the period. 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 Cumulative amount paid for payment from future revenues from spectrum obligation Cumulative amount paid for payment from future revenues from spectrum obligation. License Expiration Date License expiration date Date which license is set to establish a new expiration date must be form in CCYY-MM-DD format. Lease Term Lease term Term of the operating Leases, n 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Annual Rent Increase Percenatge Percenatge of annual rent increases Percentage of annual rant increases.