Accounts receivable, net of allowance of $30,000 Accrued bond interest receivable Additional paid-in capital Accounts receivable, allowance CONDENSED BALANCE SHEETS [Abstract] Net income per share - Basic (in dollars per share) Amortization of bond discount Cash and cash equivalents Accounts receivable Increase (Decrease) in Accounts Receivable Changes in operating assets and liabilities: Accounts payable Accrued expenses Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Common stock, authorized (in shares) Common stock, issued (in shares) Common stock, outstanding (in shares) Balance (in shares) Balance (in shares) Common stock, $.01 par value; authorized 32,500,000 shares; issued and outstanding 10,722,401 shares Stock-Based Compensation Expense for Stock Options [Abstract] Share-Based Payment Arrangement, Recognized Amount [Abstract] Total current liabilities Liabilities, Current Current liabilities: Deferred income taxes Unexpired subscription revenue Deferred Revenue, Current Unexpired subscription revenue, less current portion Deferred Revenue, Noncurrent Depreciation and amortization Net income per share - Diluted (in dollars per share) Stock-based compensation expense Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Stock-based compensation CONDENSED STATEMENTS OF OPERATIONS [Abstract] Less: Shares which could be repurchased under treasury stock method (in shares) Incremental Common Shares Attributable to Dilutive Effect of Equity Unit Purchase Agreements Potential shares exercisable under stock option plans (in shares) Goodwill Marketable Securities Total liabilities Liabilities Total liabilities and stockholders' equity Liabilities and Equity LIABILITIES AND STOCKHOLDERS' EQUITY Amortized Cost Held-to-maturity securities - treasury bills Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from investing activities: Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from operating activities: Net income Net income Recently Issued Accounting Standards [Abstract] Other income Nonoperating Income (Expense) Income from operations Operating Income (Loss) Operating revenues Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Other current assets Other Assets, Current Preferred stock, authorized (in shares) Preferred stock, issued (in shares) Preferred stock, par value (in dollars per share) Proceeds from held-to-maturity securities - treasury bills Property and equipment, net Purchase of held-to-maturity securities - treasury bills Payments to Acquire Held-to-Maturity Securities Purchase of property and equipment Payments to Acquire Property, Plant, and Equipment Related Party Transactions Related Party Transactions Disclosure [Text Block] Accumulated deficit Stock-based Compensation Expense for Stock Options Selling, general and administrative expenses CONDENSED STATEMENTS OF CASH FLOWS [Abstract] CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY [Abstract] Stockholders' equity: Total current assets Assets, Current Current assets: US Treasuries [Member] Weighted average number of common shares outstanding - Diluted (in shares) Weighted average number of common shares outstanding - diluted (in shares) Weighted average number of common shares outstanding - Basic (in shares) Weighted average number of common shares outstanding - basic (in shares) Common Stock [Member] Cost and Fair Value of Marketable Securities Debt Securities, Held-to-Maturity [Table] Total assets Assets Financial Instruments [Domain] Stock-Based Compensation Share-Based Payment Arrangement [Text Block] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Statement [Table] Antidilutive Securities, Name [Domain] ASSETS Assets [Abstract] Statement [Line Items] Cash and Cash Equivalents and Marketable Securities Measured at Fair Value on Recurring Basis Level 1 [Member] Level 2 [Member] Level 3 [Member] Fair Value Measurements Supplemental Disclosures of Noncash Investing Activities Increase (Decrease) in Stockholders' Equity [Roll Forward] Unexpired subscription revenue Other assets Other Assets, Noncurrent Operating expenses: Total operating expenses Operating Expenses Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities [Axis] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Net Income per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities Excluded from Computation [Abstract] Schedule of Held-to-Maturity Securities [Line Items] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Common stock, par value (in dollars per share) Data and product costs Total stockholders' equity Balance Balance Equity, Attributable to Parent Provision for income taxes Income Tax Expense (Benefit) Due in one year or less Preferred stock, $.01 par value; authorized 5,000,000 shares; none issued Statement, Equity Components [Axis] Additional Paid-in Capital [Member] Accumulated Deficit [Member] Equity Component [Domain] Noncash transfer of deposits Stock Options [Member] Net Income per Share Adjustments to reconcile net income to net cash used in operating activities: Accounts payable Accounts Payable, Current Accrued expenses Accrued Liabilities, Current Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Fair Value Assets, Fair Value Disclosure Fair Value, Measurement Frequency [Domain] Fair Value Hierarchy [Domain] Recurring [Member] Basis of Presentation [Abstract] Marketable Securities [Abstract] Fair Value, Hierarchy [Axis] Measurement Frequency [Axis] Commitments and Contingencies [Abstract] Fair Value Measurements [Abstract] Stock-Based Compensation [Abstract] Cash and Cash Equivalents and Marketable Securities Measured at Fair Value on Recurring Basis [Abstract] Assets, Fair Value Disclosure [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Related Party Transactions [Abstract] Supplemental Disclosures of Noncash Investing Activities [Abstract] Other current assets Increase (Decrease) in Other Current Assets Other assets Increase (Decrease) in Other Noncurrent Assets Computation of Basic and Diluted Net Income per Share Maturities of Marketable Securities Financial Instrument [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Recently Issued Accounting Standards Accounting Standards Update and Change in Accounting Principle [Text Block] Selling, General and Administrative Expenses [Member] Selling, General and Administrative Expenses [Member] Data and Product Costs [Member] Cost of Sales [Member] Other-than-temporary impairment loss Other-than-temporary Impairment Loss, Debt Securities, Held-to-Maturity, before Tax Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] Deferred taxes on income, net Revenue Recognition [Abstract] Revenue Recognition Revenue from Contract with Customer [Text Block] Operating lease right-to-use asset Operating Lease, Right-of-Use Asset Net 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 end of period Cash and cash equivalents at beginning of period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Current portion of operating lease liability Operating lease liability, less current portion Operating Lease, Liability, Noncurrent Gross Unrealized Gain (Loss) Operating lease right-to-use asset, net Operating Lease, Right-of-Use Asset, Periodic Reduction Fair Value Held-to-maturity securities Debt Securities, Held-to-Maturity, Fair Value [Abstract] Debt Securities, Held-to-Maturity, Fair Value [Abstract] Cover [Abstract] Document Type Document Quarterly Report Document Transition Report Entity Interactive Data Current Amendment Flag Document Fiscal Year Focus Document Fiscal Period Focus Document Period End Date Entity Registrant Name Entity Central Index Key Entity File Number Entity Tax Identification Number Entity Incorporation, State or Country Code Current Fiscal Year End Date Entity Current Reporting Status Entity Shell Company Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Address, Address Line One Entity Address, Address Line Two Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Entity Common Stock, Shares Outstanding