Battery & Energy Products Segments [Axis] Communications Systems Research and Development Expense Income Statement Location [Axis] Selling, General and Administrative Expenses Trademarks [Member] Finite-Lived Intangible Assets by Major Class [Axis] Patents and Technology Customer Relationships Distributor Relationships Stock Options Component Of Share Based Compensation [Axis] Employee Restricted Stock CEO Restricted Stock expense Board of Directors Stock Grant Discontinued Operations Corporate Document And Entity Information Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Current Fiscal Year End Date Is Entity a Well-known Seasoned Issuer? Is Entity a Voluntary Filer? Is Entity's Reporting Status Current? Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Document Fiscal Period Focus Document Fiscal Year Focus Statement of Financial Position [Abstract] Current assets: Cash and cash equivalents Restricted cash Trade accounts receivable, net of allowance for doubtful account Inventories, net Prepaid expenses and other current assets Due from insurance company Deferred income taxes Total current assets Property, equipment and improvements, net Goodwill Other intangible assets, net Security deposits and other non-current assets Total assets Current liabilities: Accounts payable Accrued compensation and related benefits Accrued expenses and other current liabilities Accrued income taxes Total current liabilities Deferred income taxes Other non-current liabilities Total liabilities Commitments and contingencies Shareholders' equity: Preferred stock - par value $.10 per share; authorized 1,000,000 shares; none issued Common stock - par value $.10 per share; authorized 40,000,000 shares; issued - 18,974,211 shares at June 28, 2015 and 18,941,544 shares at December 31, 2014 Capital in excess of par value Accumulated deficit Accumulated other comprehensive loss Treasury stock - at cost; 3,090,225 shares at June 28, 2015 and 1,600,731 shares at December 31, 2014 Total Ultralife equity Noncontrolling interest Total shareholders' equity Total liabiltiies and shareholders' equity Trade accounts receivable allowance for doubtful accounts Preferred stock - par value (in dollars per share) Preferred stock, shares authorized Preferred stock, shares issued Common stock, par value (in dollars per share) Common stock, shares authorized Common stock, shares issued Treasury stock shares Income Statement [Abstract] Revenues Cost of products sold Gross profit Operating expenses: Research and development Selling, general and administrative Total operating expenses Operating income (loss) Other (expense) income: Interest income Interest and financing expense Miscellaneous Income (Loss) from continuing operations before income taxes Income tax provision Net income (loss) from continuing operations Income (loss) from discontinued operations, net of tax Net Income (loss) Net loss attributable to noncontrolling interest Net Income (loss) attributable to Ultralife Other comprehensive income: Foreign currency translation adjustments Comprehensive loss attributable to Ultralife Net income (loss) per share attributable to Ultralife common shareholders - Basic: Continuing operations (in dollars per share) Discontinued operations (in dollars per share) Total (in dollars per share) Net income per share attributable to Ultralife common shareholders - Diluted: Continuing operations (in dollars per share) Discontinued operations (in dollars per share) Total (in dollars per share) Weighted average shares outstanding - basic Potential common shares Weighted average shares outstanding - diluted Statement of Cash Flows [Abstract] OPERATING ACTIVITIES: Net (loss) income Loss (gain) from discontinued operations, net of tax Depreciation and amortization of financing fees Amortization of intangible assets Loss on long-lived asset impairment' Foreign exchange loss Stock-based compensation Changes in deferred income taxes Changes in operating assets and liabilities: Accounts receivable Inventories Prepaid expenses and other assets Accounts payable and other liabilities Net cash provided by (used in) operating activities INVESTING ACTIVITIES: Cash paid for property, equipment and improvements Change in restricted cash Net cash used in investing activities FINANCING ACTIVITIES: Cash paid to repurchase treasury stock Proceeds from the issuance of common stock Return of security deposit Net cash (used in) provided by financing activities Effect of exchange rate changes on cash and cash equivalents (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Construction in progress included in accounts payable Note 1 - Basis Of Presentation Basis of Presentation Note 2 - Share Repurchase Program Share Repurchase Program Note 3 - Relocation Relocation Note 4 - Inventories Inventories Note 5 - Property Equipment And Improvements Property, Equipment and Improvements Note 6 - Goodwill Intangible Assets And Long Term Assets Goodwill, Intangible Assets and Long Term Assets Note 7 - Revolving Credit Agreement Revolving Credit Agreement Note 8 - Shareholders Equity Shareholders' Equity Note 9 - Income Taxes Income Taxes Note 10 - Earnings Per Share Earnings Per Share Note 11 - Commitments And Contingencies Commitments and Contingencies Note 12 - Business Segment Information Business Segment Information Note 13 - Fair Value Of Financial Instruments Fair Value of Financial Instruments Note 14 - Fire At Manufacturing Facility Fire at Manufacturing Facility Note 15 - Recent Accounting Pronouncements And Developments Recent Accounting Pronouncements and Developments Note 4 - Inventories Tables Inventories Tables Note 5 - Property Equipment And Improvements Tables Property, Equipment and Improvements Tables Depreciation expense Note 6 - Goodwill Intangible Assets And Long Term Assets Tables Schedule of Goodwill Activity by Segment Schedule of Intangible Assets Schedule of Amortization of Intangible Assets Note 8 - Shareholders Equity Tables Components of Stock Compensation Expense Schedule of Stock Option Activity Note 9 - Income Taxes Tables Schedule of tax provision components Schedule of Unrecognized Tax Benefits Note 11 - Commitments And Contingencies Tables Rollforward of Accrued Warranty Obligations Note 12 - Business Segment Information Tables Segment disclosure Note 2 - Share Repurchase Program Details Narrative Maximum number of shares the Company is authorized to repurchase Additional number of shares the Company is authorized to repurchase Shares repurchased Cost of shares repurchased Balance - shares authorized to be repurchased Note 3 - Relocation Details Narrative Government reimbursement received - China factory move Government reimbursement recognized - China factory move Expenses recognized - China factory move Note 4 - Inventories Detail Raw materials Work in process Finished products Total Note 5 - Property Equipment And Improvements Details Land Buildings and leasehold improvements Machinery and equipment Furniture and fixtures Computer hardware and software Construction in progress Total Less-Accumulated depreciation Total Note 5 - Property Equipment And Improvements Details Narrative Depreciation expense Statement [Table] Statement [Line Items] Goodwill - beginning Effect of foreign currency translation Goodwill - ending Amortization expense Cost Accumulated Amortization Net Note 7 - Revolving Credit Agreement Details Narrative Line of Credit Facility, Maximum Borrowing Capacity Letter of credit sub-facility Line of Credit Maximum Borrowing Capacity may be increased in the last six months of the term Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Line of Credit Facility, Amount Outstanding Line of Credit Facility, Remaining Borrowing Capacity Unrestricted Cash on hand ComponentOfShareBasedCompensationAxis [Axis] Stock compensation expense Note 8 - Shareholders Equity Option Rollforward Details Narrative Options outstanding Options outstanding - weighted average exercise price Options outstanding - weighted average remaining contractual term (years) Options outstanding - aggregate intrinsic value Options granted Options granted - weighted average exercise price Options exercised Options exercised - weighted average exercise price Options forfeited or expired Options forfeited or expired - weighted average exercise price Options vested and expected to vest Options vested and expected to vest - weighted average exercise price Options vested and expected to vest - weighted average remaining contractual term (years) Options vested and expected to vest - aggregate intrinsic value Options Exercisable Options exercisable - weighted average exercise price Options exercisable - weighted average remaining contractual term (years) Options exercisable - aggregate intrinsic value Note 8 - Shareholders Equity Details Narrative Unrecognized stock option compensation cost Weighted average period over which unrecognized stock option compensation cost will be recognized (in years) Cash received upon the exercise of stock options Unrecognized compensation cost related to restricted stock awards Unvested restricted stock units - President & CEO Shares of restricted stock awarded to certain employees Note 9 - Income Taxes Details Foreign tax provision Federal tax provision State tax provision Deferred tax provision Total income tax provision Note 9 - Income Taxes Unrecognized Tax Benefits Details Unrecognized tax benefits - beginning Settlements of examinations Unrecognized tax benefits - ending Note 9 - Income Taxes Details Narrative Net operating loss carryforward Net operating loss carryforward - domestic Net operating loss carryforward - foreign Tax credit carryforwards Net operating loss carryforward for which a benefit will be recorded in capital when realized Income tax rate Alternative minimum tax provision recorded Note 10 - Earnings Per Share Details Narrative Employee stock options excluded from calculation of diluted earnings per share Incremental shares included in EPS denominator due to share based payment arrangements Number of Employee stock options included in calculation of diluted earnings per share Number of restricted shares included in calculation of diluted earnings per share Note 11 Commitments And Contingencies Warranty Obligations Details Accrued warranty obligations - beginning Accrual for warranties issued Settlements made Accrued warranty obligations - ending Note 11 Commitments And Contingencies Detail Narrative Unrecorded Unconditional Purchase Obligation Revenue Segment contribution Interest, financing and miscellaneous expense, net Income tax provision Income (loss) from discontinued operations Noncontrolling interest Net loss attributable to Ultralife Total assets Note 14 - Fire At Manufacturing Facility Details Narrative Business Interruption Loss, Gross Proceeds from Insurance Settlement, Operating Activities Gain on Business Interruption Insurance Recovery Insurance Settlements Receivable Business Interruption, Insurance Deductible Business Interruption Loss, Gross Business Interruption, Insurance Deductible Assets, Current Liabilities, Current Deferred Tax Liabilities, Gross Liabilities Treasury Stock, Value Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Stockholders' Equity Attributable to Parent Liabilities and Equity Gross Profit Operating Expenses Interest Expense Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Net Income (Loss) Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Parent Income (Loss) from Continuing Operations, Per Diluted Share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Earnings Per Share, Diluted Net Cash Provided by (Used in) Operating Activities Payments to Acquire Property, Plant, and Equipment Increase (Decrease) in Restricted Cash Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Financing Activities Cash and Cash Equivalents, Period Increase (Decrease) Inventory Disclosure [Text Block] Property, Plant and Equipment, Gross Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, Plant and Equipment, Net Depreciation Finite-Lived Intangible Assets, Accumulated Amortization Finite-Lived Intangible Assets, Net Unrecognized Tax Benefits Product Warranty Accrual