Document and Entity Information [Abstract] Statement, Equity Components [Axis] Equity Component [Domain] Assets Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Accounts receivable, net of allowances of $757 and $947 Accounts Receivable, Net, Current Allowances for accounts receivable Allowance for Doubtful Accounts Receivable, Current Inventories, net Inventory, Net Deferred contract costs Deferred Costs, Current Deferred tax assets Deferred Tax Assets, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Total current assets Assets, Current, Total Total current assets Property and equipment, net Property, Plant and Equipment, Net Long-term inventory Inventory, Noncurrent Patents and licenses, net Finite-Lived Intangible Assets, Net Deferred tax assets Deferred Tax Assets, Net, Noncurrent Long-term accounts receivable Accounts Receivable, Net, Noncurrent Other long-term assets Other Assets, Noncurrent Total assets Assets, Total Total assets Liabilities and Shareholders' Equity Liabilities and Equity [Abstract] Accounts payable Accounts Payable, Current Accrued expenses Accrued Liabilities, Current Deferred revenue Deferred Revenue, Current Current maturities of long-term debt Long-term Debt, Current Maturities Total current liabilities Liabilities, Current, Total Total current liabilities Long-term debt, less current maturities Long-term Debt, Excluding Current Maturities Deferred revenue Deferred Revenue, Noncurrent Other long-term liabilities Other Liabilities, Noncurrent Other long-term liabilities Total liabilities Liabilities, Total Total liabilities Commitments and contingencies (See Note F) Commitments and Contingencies Shareholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.01 par value: Shares authorized: 30,000,000 shares at March 31, 2011 and 2012; no shares issued and outstanding at March 31, 2011 and 2012 Preferred Stock, Value, Issued Preferred stock, par value Preferred Stock, Par or Stated Value 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, no par value: Shares authorized: 200,000,000 at March 31, 2011 and 2012; shares issued: 30,312,758 and 30,445,479 at March 31, 2011 and 2012; shares outstanding: 22,893,803 and 22,785,258 at March 31, 2011 and 2012 Common Stock, Value, Issued Common stock, no par value Common Stock, No Par Value Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Additional paid-in capital Additional Paid in Capital Treasury stock: 7,431,897 common shares at March 31, 2011 and 7,660,221 at March 31, 2012 Treasury Stock, Value Treasury stock: 7,431,897 common shares at March 31, 2011 and 7,660,221 at March 31, 2012 Treasury stock, shares Treasury Stock, Shares Shareholder notes receivable Receivable from Shareholders or Affiliates for Issuance of Capital Stock Shareholder notes receivable Retained deficit Retained Earnings (Accumulated Deficit) Total shareholders' equity Stockholders' Equity Attributable to Parent, Total Total shareholders' equity Total liabilities and shareholders' equity Liabilities and Equity, Total Total liabilities and shareholders' equity Product revenue Sales Revenue, Goods, Net Service revenue Sales Revenue, Services, Net Total revenue Revenues, Total Total revenue Cost of product revenue Cost of Goods Sold Cost of service revenue Cost of Services Total cost of revenue Cost of Revenue, Total Total cost of revenue Gross profit Gross Profit Gross profit Operating expenses: Operating Expenses [Abstract] General and administrative General and Administrative Expense Sales and marketing Selling and Marketing Expense Research and development Research and Development Expense Total operating expenses Operating Expenses, Total Total operating expenses Income (loss) from operations Operating Income (Loss) Income (loss) from operations Other income (expense): Nonoperating Income (Expense) [Abstract] Interest expense Interest Expense Interest expense (Loss) gain on sale of OTA contract receivables Gain (Loss) on Contract Termination Extinguishment of debt Gains (Losses) on Extinguishment of Debt Dividend and interest income Investment Income, Interest and Dividend Dividend and interest income Total other income (expense) Nonoperating Income (Expense), Total Total other income (expense) Income (loss) before income tax Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income (loss) before income tax Income tax expense (benefit) Income Tax Expense (Benefit) Income tax expense (benefit) Net income (loss) Net Income (Loss) Attributable to Parent Net income (loss) Basic net income (loss) per share attributable to common shareholders Earnings Per Share, Basic Weighted-average common shares outstanding Weighted Average Number of Shares Outstanding, Basic Diluted net income (loss) per share Earnings Per Share, Diluted Weighted-average common shares and share equivalents outstanding Weighted Average Number of Shares Outstanding, Diluted Statement [Table] Statement [Line Items] Common Stock Balance, March 31, 2009, shares Shares, Outstanding Beginning balance, shares Common Stock Additional Paid-in Capital Beginning balance Treasury Stock Stockholders' Notes Receivable Accumulated Other Comprehensive Loss Retained Earnings (Deficit) Stock Issued During Period Shares Issued for Services Issuance of stock and warrants for services, shares Issuance of stock and warrants for services, shares Stock Issued During Period Value Issued for Services Issuance of stock and warrants for services Issuance of stock and warrants for services Exercise of stock options and warrants for cash, shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of stock options and warrants for cash Stock Issued During Period, Value, Stock Options Exercised Tax benefit from exercise of stock options Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Treasury stock purchase, shares Treasury Stock, Shares, Acquired Treasury stock purchase, shares Treasury stock purchase Treasury Stock, Value, Acquired, Cost Method Treasury stock purchase Unrealized gain on short-term investments Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Comprehensive Loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive income (loss) Ending balance, shares Ending balance Shares issued under Employee Stock Purchase Plan, shares Stock Issued During Period, Shares, Employee Stock Purchase Plans Shares issued under Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Collection of shareholder notes receivable Proceeds from Related Party Debt Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock-based compensation expense Share-based Compensation Deferred income tax (benefit) Deferred Income Tax Expense (Benefit) Loss on sale of assets Gain (Loss) on Disposition of Assets Loss on sale of assets Change in bad debt expense Provision for Doubtful Accounts Extinguishment of debt Other Noncash Income Extinguishment of debt Other Other Noncash Income (Expense) Other Accounts receivable Increase (Decrease) in Accounts Receivable Accounts receivable Inventories Increase (Decrease) in Inventories Inventories Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other assets Deferred contract costs Increase (Decrease) in Deferred Charges Deferred revenue Increase (Decrease) in Deferred Revenue Accounts payable Increase (Decrease) in Accounts Payable Accrued expenses Increase (Decrease) in Other Accrued Liabilities Accrued expenses Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Net cash provided by (used in) operating activities Investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Purchase of property and equipment Payments to Acquire Property, Plant, and Equipment Purchase of property and equipment Purchase of property and equipment leased to customers under PPAs Payments to Acquire Other Productive Assets Purchase of property and equipment leased to customers under PPAs Purchase of short-term investments Payments to Acquire Short-term Investments Purchase of short-term investments Sale of short-term investments Proceeds from Sale of Short-term Investments Additions to patents and licenses Payments to Acquire Intangible Assets Additions to patents and licenses Proceeds from disposal of equipment Proceeds from Sale of Property, Plant, and Equipment Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Net cash used in investing activities Financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from issuance of long-term debt Proceeds from Issuance of Debt Proceeds from shareholder notes Deferred financing and offering costs Payments of Financing Costs Deferred financing and offering costs Repurchase of common stock into treasury Payments for Repurchase of Common Stock Repurchase of common stock into treasury Payment of long-term debt Repayments of Long-term Debt Payment of long-term debt Excess benefit for deferred taxes on stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Proceeds from issuance of common stock Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Net increase (decrease) in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Cash paid for income taxes Income Taxes Paid Supplemental disclosure of non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Shares issued from treasury for stock note receivable Other Significant Noncash Transaction, Value of Consideration Given Shares surrendered into treasury for stock option exercise Other Significant Noncash Transaction, Value of Consideration Received DESCRIPTION OF BUSINESS Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Description of Business [Abstract] Description of Business [Abstract] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies [Abstract] Summary of Significant Accounting Policies [Abstract] RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions [Abstract] LONG-TERM DEBT Long-term Debt [Text Block] Long-Term Debt [Abstract] Long-Term Debt [Abstract] INCOME TAXES Income Tax Disclosure [Text Block] Income Taxes [Abstract] Income Taxes [Abstract] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies [Abstract] Commitments and Contingencies [Abstract] SHAREHOLDERS' EQUITY Stockholders' Equity Note Disclosure [Text Block] Shareholders' Equity [Abstract] Shareholders' Equity [Abstract] STOCK OPTIONS AND WARRANTS Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock Options and Warrants [Abstract] Stock Options and Warrants [Abstract] SEGMENT DATA Segment Reporting Disclosure [Text Block] Segment Data [Abstract] Segment Data [Abstract] SUBSEQUENT EVENTS Subsequent Events [Text Block] Subsequent Events [Abstract] Subsequent Events [Abstract] QUARTERLY FINANCIAL DATA (UNAUDITED) Quarterly Financial Information [Text Block] Quarterly Financial Data [Abstract] Quarterly Financial Data [Abstract] Amendment Flag Current Fiscal Year End Date Document Period End Date Document Type Entity Central Index Key Entity Common Stock, Shares Outstanding Entity Current Reporting Status Entity Filer Category Entity Registrant Name Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Public Float Document Fiscal Period Focus Document Fiscal Year Focus Consolidated Balance Sheets [Abstract] Consolidated Statements of Operations [Abstract] Statement of Shareholders' Equity [Abstract] Consolidated Statements of Cash Flows [Abstract]