0000 - Document - Document And Entity Information link:presentationLink link:definitionLink link:calculationLink 0010 - Statement - CONSOLIDATED BALANCE SHEETS link:presentationLink link:definitionLink link:calculationLink 0020 - Statement - CONSOLIDATED BALANCE SHEETS (Parentheticals) link:presentationLink link:definitionLink link:calculationLink 0030 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) link:presentationLink link:definitionLink link:calculationLink 0040 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY link:presentationLink link:definitionLink link:calculationLink 0060 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS link:presentationLink link:definitionLink link:calculationLink 1010 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies link:presentationLink link:definitionLink link:calculationLink 1011 - Disclosure - Discontinued Operations and Asset Sale link:presentationLink link:definitionLink link:calculationLink 1020 - Disclosure - Marketable Securities link:presentationLink link:definitionLink link:calculationLink 1030 - Disclosure - Intangible Assets link:presentationLink link:definitionLink link:calculationLink 1040 - Disclosure - Inventories link:presentationLink link:definitionLink link:calculationLink 1050 - Disclosure - Property and Equipment link:presentationLink link:definitionLink link:calculationLink 1060 - Disclosure - Leases link:presentationLink link:definitionLink link:calculationLink 1070 - Disclosure - Accrued Liabilities link:presentationLink link:definitionLink link:calculationLink 1080 - Disclosure - Commitments and Contingencies link:presentationLink link:definitionLink link:calculationLink 1090 - Disclosure - Debt link:presentationLink link:definitionLink link:calculationLink 1100 - Disclosure - Share-Based Payments link:presentationLink link:definitionLink link:calculationLink 1110 - Disclosure - Significant Customers link:presentationLink link:definitionLink link:calculationLink 1120 - Disclosure - Fair Value Measurements link:presentationLink link:definitionLink link:calculationLink 1130 - Disclosure - Income Taxes link:presentationLink link:definitionLink link:calculationLink 11301 - Disclosure - Capital Structure: Class A Redeemable Preferred Stock link:presentationLink link:definitionLink link:calculationLink 1140 - Disclosure - Geographic Sales Information link:presentationLink link:definitionLink link:calculationLink 1150 - Disclosure - The Impact of Covid-19 link:presentationLink link:definitionLink link:calculationLink 1160 - Disclosure - Subsequent events link:presentationLink link:definitionLink link:calculationLink 9966620 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies (Policies) link:presentationLink link:definitionLink link:calculationLink 99666301 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies (Tables) link:presentationLink link:definitionLink link:calculationLink 996663011 - Disclosure - Discontinued Operations and Asset Sale (Tables) link:presentationLink link:definitionLink link:calculationLink 99666302 - Disclosure - Marketable Securities (Tables) link:presentationLink link:definitionLink link:calculationLink 99666303 - Disclosure - Intangible Assets (Tables) link:presentationLink link:definitionLink link:calculationLink 99666304 - Disclosure - Inventories (Tables) link:presentationLink link:definitionLink link:calculationLink 99666305 - Disclosure - Property and Equipment (Tables) link:presentationLink link:definitionLink link:calculationLink 99666306 - Disclosure - Leases (Tables) link:presentationLink link:definitionLink link:calculationLink 99666307 - Disclosure - Accrued Liabilities (Tables) link:presentationLink link:definitionLink link:calculationLink 99666308 - Disclosure - Debt (Tables) link:presentationLink link:definitionLink link:calculationLink 99666309 - Disclosure - Share-Based Payments (Tables) link:presentationLink link:definitionLink link:calculationLink 99666310 - Disclosure - Significant Customers (Tables) link:presentationLink link:definitionLink link:calculationLink 99666311 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:definitionLink link:calculationLink 99666312 - Disclosure - Income Taxes (Tables) link:presentationLink link:definitionLink link:calculationLink 996663121 - Disclosure - Capital Structure: Class A Redeemable Preferred Stock (Tables) link:presentationLink link:definitionLink link:calculationLink 99666313 - Disclosure - Geographic Sales Information (Tables) link:presentationLink link:definitionLink link:calculationLink 99666401 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664010 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies - Allowance for Doubtful Accounts Activity (Details) link:presentationLink link:definitionLink link:calculationLink 996664011 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies - Deferred Revenue and Associated Costs of Goods Sold and Gross Profit (Details) link:presentationLink link:definitionLink link:calculationLink 996664012 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies - Revenue by Product Group and Major Regions (Details) link:presentationLink link:definitionLink link:calculationLink 996664013 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies - Warranty Liability (Details) link:presentationLink link:definitionLink link:calculationLink 996664014 - Disclosure - Business Description, Basis of Presentation and Significant Accounting Policies - Earnings Per Share (Details) link:presentationLink link:definitionLink link:calculationLink 996664015 - Disclosure - Discontinued Operations and Asset Sale (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664016 - Disclosure - Discontinued Operations and Asset Sale - Loss on Assets Sale (Details) link:presentationLink link:definitionLink link:calculationLink 996664017 - Disclosure - Discontinued Operations and Asset Sale - Major Classes of Assets and Liabilities of Disposed Business (Details) link:presentationLink link:definitionLink link:calculationLink 996664018 - Disclosure - Discontinued Operations and Asset Sale - Results of Discontinued Operations (Details) link:presentationLink link:definitionLink link:calculationLink 99666402 - Disclosure - Marketable Securities (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664020 - Disclosure - Marketable Securities - Available-for-sale Securities by Major Security Type (Details) link:presentationLink link:definitionLink link:calculationLink 996664021 - Disclosure - Marketable Securities - Maturities of Available-for-sale Securities (Details) link:presentationLink link:definitionLink link:calculationLink 996664022 - Disclosure - Marketable Securities - Available-for-sale Marketable Securities in Gross Unrealized Loss Position (Details) link:presentationLink link:definitionLink link:calculationLink 99666403 - Disclosure - Intangible Assets (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664030 - Disclosure - Intangible Assets (Details) link:presentationLink link:definitionLink link:calculationLink 996664031 - Disclosure - Intangible Assets - Estimated Future Amortization Expense of Intangible Assets (Details) link:presentationLink link:definitionLink link:calculationLink 99666404 - Disclosure - Inventories (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664040 - Disclosure - Inventories - Inventories (Details) link:presentationLink link:definitionLink link:calculationLink 99666405 - Disclosure - Property and Equipment (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664050 - Disclosure - Property and Equipment - Property and Equipment (Details) link:presentationLink link:definitionLink link:calculationLink 99666406 - Disclosure - Leases (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664060 - Disclosure - Leases - Rent expense (Details) link:presentationLink link:definitionLink link:calculationLink 996664061 - Disclosure - Leases - Supplemental cash flow information (Details) link:presentationLink link:definitionLink link:calculationLink 996664062 - Disclosure - Leases - Supplemental balance sheet information (Details) link:presentationLink link:definitionLink link:calculationLink 996664063 - Disclosure - Leases - Maturities of operating lease liabilities (Details) link:presentationLink link:definitionLink link:calculationLink 99666407 - Disclosure - Accrued Liabilities - Accrued Liabilities (Details) link:presentationLink link:definitionLink link:calculationLink 99666408 - Disclosure - Commitments and Contingencies (Details Textual) link:presentationLink link:definitionLink link:calculationLink 99666409 - Disclosure - Debt (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664090 - Disclosure - Debt (Schedule Of Warrants Valuation Assumptions) (Details) link:presentationLink link:definitionLink link:calculationLink 996664091 - Disclosure - Debt (Schedule of carrying value of Notes and Warrants) (Details) link:presentationLink link:definitionLink link:calculationLink 996664092 - Disclosure - Debt (Schedule of maturities of principal amount contained in the Notes) (Details) link:presentationLink link:definitionLink link:calculationLink 996664093 - Disclosure - Debt (Schedule of paycheck protection program loan liabilities) (Details) link:presentationLink link:definitionLink link:calculationLink 99666410 - Disclosure - Share-Based Payments (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664101 - Disclosure - Share-Based Payments - Black-scholes Assumptions (Details) link:presentationLink link:definitionLink link:calculationLink 996664102 - Disclosure - Share-Based Payments - Stock Option Activity (Details) link:presentationLink link:definitionLink link:calculationLink 996664103 - Disclosure - Share-Based Payments - Employee Stock Purchase Plans (Details) link:presentationLink link:definitionLink link:calculationLink 99666411 - Disclosure - Significant Customers (Details Textual) link:presentationLink link:definitionLink link:calculationLink 99666412 - Disclosure - Fair Value Measurements - Fair Value of Financial Instruments (Details) link:presentationLink link:definitionLink link:calculationLink 99666413 - Disclosure - Income Taxes (Details Textual) link:presentationLink link:definitionLink link:calculationLink 996664131 - Disclosure - Income Taxes - Consolidated Income Before Taxes (Details) link:presentationLink link:definitionLink link:calculationLink 996664132 - Disclosure - Income Taxes - Provision for Income Taxes (Details) link:presentationLink link:definitionLink link:calculationLink 996664133 - Disclosure - Income Taxes - Income Tax (Provision) for Federal Statutory Corporate Income Tax Rate (Details) link:presentationLink link:definitionLink link:calculationLink 996664134 - Disclosure - Income Taxes - Net Deferred Tax Assets and Liabilities (Details) link:presentationLink link:definitionLink link:calculationLink 9966641341 - Disclosure - Income Taxes - Schedule of taxes paid by jurisdiction (Details) link:presentationLink link:definitionLink link:calculationLink 996664135 - Disclosure - Income Taxes - Reconciliation of Uncertain Tax Positions (Details) link:presentationLink link:definitionLink link:calculationLink 9966641351 - Disclosure - Capital Structure: Class A Redeemable Preferred Stock (Details Textual) link:presentationLink link:definitionLink link:calculationLink 9966641352 - Disclosure - Capital Structure: Class A Redeemable Preferred Stock - Changes in Temporary Equity (Details) link:presentationLink link:definitionLink link:calculationLink 99666414 - Disclosure - Geographic Sales Information (Details 1 - Textual) link:presentationLink link:definitionLink link:calculationLink 996664141 - Disclosure - Geographic Sales Information - Revenue by Geographic Area, Discontinued Operations (Details) link:presentationLink link:definitionLink link:calculationLink 99666415 - Disclosure - Subsequent events (Details Textual) link:presentationLink link:definitionLink link:calculationLink