Entity Central Index Key The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the United States. Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Accrued and other liabilities current. Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Marketable securities Marketable Securities Accounts receivable, net Accounts Receivable Net Current Inventories Inventory Net Restricted cash Restricted Cash And Cash Equivalents Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Deferred tax assets, non-current Deferred Tax Assets Net Noncurrent Intangible assets, net Intangible Assets Net Excluding Goodwill Goodwill Goodwill Other non-current assets Other Assets Noncurrent Total assets Assets LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued and other current liabilities Accrued And Other Liabilities Current Income taxes payable Accrued Income Taxes Current Deferred revenue, current Deferred Revenue Current Total current liabilities Liabilities Current Other long-term liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 14) Commitments And Contingencies Shareholders' equity: Stockholders Equity [Abstract] Preference shares, $0.00045 par value per share, 20,000,000 shares authorized and no shares issued and outstanding at January 31, 2018 and January 31, 2017, respectively Preferred Stock Value Ordinary shares, $0.00045 par value per share, 200,000,000 shares authorized at January 31, 2018 and January 31, 2017, respectively; 33,489,614 shares issued and outstanding at January 31, 2018; 33,369,032 shares issued and outstanding at January 31, 2017 Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Retained earnings Retained Earnings Accumulated Deficit Total shareholders’ equity Stockholders Equity Total liabilities and shareholders' equity Liabilities And Stockholders Equity Preference shares, par value Preferred Stock Par Or Stated Value Per Share Preference shares, shares authorized Preferred Stock Shares Authorized Preference shares, shares issued Preferred Stock Shares Issued Preference shares, shares outstanding Preferred Stock Shares Outstanding Ordinary shares, par value Common Stock Par Or Stated Value Per Share Ordinary shares, shares authorized Common Stock Shares Authorized Ordinary shares, shares issued Common Stock Shares Issued Ordinary shares, shares outstanding Common Stock Shares Outstanding Income Statement [Abstract] Revenue Revenues Cost of revenue Cost Of Revenue Gross profit Gross Profit Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense Selling, general and administrative Selling General And Administrative Expense Total operating expenses Operating Expenses Income from operations Operating Income Loss Other income, net Nonoperating Income Expense Income before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Provision for income taxes Income Tax Expense Benefit Net income Net Income Loss Net income per share attributable to ordinary shareholders: Earnings Per Share [Abstract] Basic Earnings Per Share Basic Diluted Earnings Per Share Diluted Weighted-average shares used to compute net income per share attributable to ordinary shareholders: Weighted Average Number Of Shares Outstanding [Abstract] Basic Weighted Average Number Of Shares Outstanding Basic Diluted Weighted Average Number Of Diluted Shares Outstanding Statement Of Income And Comprehensive Income [Abstract] Net income Other comprehensive loss, net of tax: Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Unrealized losses on investments Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Other comprehensive loss, net of tax Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent Comprehensive income Comprehensive Income Net Of Tax Shares issued during the period as a result of restricted stock units vested. Value of shares issued during the period as a result of restricted stock units vested. Cumulative effect adjustment of a new accounting principle upon adoption. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Outstanding Ordinary Shares [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid In Capital [Member] Accumulated Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income [Member] Retained Earnings [Member] Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Beginning Balance, Amount Beginning Balance, Shares Cumulative effect of change in accounting principle Cumulative Effect Of Change In Accounting Principle Exercise of stock options, Amount Stock Issued During Period Value Stock Options Exercised Exercise of stock options, Shares Stock Issued During Period Shares Stock Options Exercised Restricted stock awards granted, Amount Stock Issued During Period Value Restricted Stock Award Gross Restricted stock awards granted, Shares Stock Issued During Period Shares Restricted Stock Award Gross Vesting of restricted stock units, Amount Stock Issued During Period Value Restricted Stock Units Vesting of restricted stock units, Shares Stock Issued During Period Shares Restricted Stock Units Employee stock purchase plan, Amount Stock Issued During Period Value Employee Stock Purchase Plan Employee stock purchase plan, Shares Stock Issued During Period Shares Employee Stock Purchase Plans Stock repurchase, Amount Stock Repurchased During Period Value Stock repurchase, Shares Stock Repurchased During Period Shares Stock-based compensation expense related to stock awards granted to employees and consultants Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Excess income tax benefit associated with stock-based compensation Adjustment To Additional Paid In Capital Income Tax Effect From Share Based Compensation Net Net unrealized losses on investments - net of taxes Ending Balance, Amount Ending Balance, Shares The increase (decrease) of deferred tax liability attributable to taxable temporary differences. Amount of cash inflow from exercise of stock options and employee stock purchase plan withholding. Amount of cash outflow associated with the payment of software license liabilities. Capital expenditures incurred but not yet paid and financing incurred for intangible and fixed asset purchases. Statement Of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation of property and equipment Depreciation Amortization of intangible assets Amortization Of Intangible Assets Amortization/accretion of marketable securities Accretion Amortization Of Discounts And Premiums Investments Stock-based compensation Share Based Compensation Other non-cash items, net Other Noncash Income Expense Changes in operating assets and liabilities, net of effects of acquisitions: Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Inventories Increase Decrease In Inventories Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Deferred tax assets Increase Decrease In Deferred Income Taxes Other non-current assets Increase Decrease In Other Noncurrent Assets Accounts payable Increase Decrease In Accounts Payable Accrued liabilities Increase Decrease In Accrued Liabilities Income taxes payable Increase Decrease In Accrued Income Taxes Payable Deferred tax liabilities Increase Decrease In Deferred Tax Liabilities Deferred revenue Increase Decrease In Deferred Revenue Other long-term liabilities Increase Decrease In Other Noncurrent Liabilities Net cash provided by operating activities Net Cash Provided By Used In Operating Activities Continuing Operations Cash flows from investing activities: Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Acquisition, net of cash acquired Payments To Acquire Businesses Net Of Cash Acquired Purchase of investments Payments To Acquire Available For Sale Securities Sales of investments Proceeds From Sale Of Available For Sale Securities Debt Maturities of investments Proceeds From Sale And Maturity Of Available For Sale Securities Purchase of property and equipment Payments To Acquire Property Plant And Equipment Net cash used in investing activities Net Cash Provided By Used In Investing Activities Continuing Operations Cash flows from financing activities: Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Proceeds from exercise of stock options and employee stock purchase plan Proceeds From Issuance Of Shares Under Incentive Equity Plan And Employee Stock Purchase Plan Stock repurchase Payments For Repurchase Of Common Stock Payment for intangible assets Payment For Software License Liabilities Net cash provided by (used in) financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Net increase in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for income taxes Income Taxes Paid Supplemental disclosure of noncash investing activities: Noncash Investing And Financing Items [Abstract] Unpaid liabilities related to intangible and fixed assets purchases Capital Expenditures Incurred But Not Yet Paid And Financing Incurred For Intangible And Fixed Asset Purchases Accounting Policies [Abstract] Organization and Summary of Significant Accounting Policies Organization Consolidation And Presentation Of Financial Statements Disclosure And Significant Accounting Policies [Text Block] Investments All Other Investments [Abstract] Financial Instruments and Fair Value Financial Instruments Disclosure [Text Block] Inventory Disclosure [Abstract] Inventories Inventory Disclosure [Text Block] Property Plant And Equipment [Abstract] Property and Equipment, Net Property Plant And Equipment Disclosure [Text Block] Goodwill And Intangible Assets Disclosure [Abstract] Intangible Assets Intangible Assets Disclosure [Text Block] Goodwill Goodwill Disclosure [Text Block] Payables And Accruals [Abstract] Accrued and Other Current Liabilities Accounts Payable Accrued Liabilities And Other Liabilities Disclosure Current [Text Block] Deferred Revenue Disclosure [Abstract] Deferred Revenue, Current Deferred Revenue Disclosure [Text Block] Other Liabilities Disclosure [Abstract] Other Long-Term Liabilities Accounts Payable Accrued Liabilities And Other Liabilities Disclosure Noncurrent [Text Block] The entire disclosure of an entity's capital stock, shares repurchased, and shares reserved for future issuance. Equity [Abstract] Capital Stock Capital Stock [Text Block] Postemployment Benefits [Abstract] Employee Benefits and Stock-based Compensation Compensation And Employee Benefit Plans [Text Block] Net Income Per Ordinary Share Earnings Per Share [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Segment Reporting [Abstract] Segment Reporting Segment Reporting Disclosure [Text Block] Related Party Transactions [Abstract] Related-Party Transactions Related Party Transactions Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Formation and business of the entity. Organization Organization Policy [Text Block] Basis of Consolidation Consolidation Policy [Text Block] Use of Estimates Use Of Estimates The entire disclosure of concentration risks existing in the entity's business and investment. Concentration of Risk Concentration Of Risk Policy [Text Block] Foreign Currency Transactions Foreign Currency Transactions And Translations Policy [Text Block] Fair Value of Financial Instruments Fair Value Of Financial Instruments Policy Disclosure of accounting policy for determining cash equivalents and marketable securities. The disclosure may also address accounting policies for investments classified as trading, available for sale, or held to maturity and may include how the entity determines whether impairments of available for sale or held to maturity investments are other than temporary, how the fair values of the entity's securities are determined, and how the entity presents the realized and unrealized gains or losses in its financial statements. Cash Equivalents and Marketable Securities Cash Equivalents And Marketable Securities Policy [Text Block] Trade Accounts Receivable and Allowances for Doubtful Accounts Receivables Policy [Text Block] Inventories Inventory Policy [Text Block] Property and Equipment Property Plant And Equipment Policy [Text Block] Internal-Use Software Internal Use Software Policy Disclosure of accounting policy for non-cancelable software license and associated liabilities. Noncancelable Software License Non Cancelable Software License Policy Policy [Text Block] Business Combinations and Intangible Assets Business Combinations Policy Disclosure of accounting policy for goodwill and in process research and development. Goodwill and In-Process Research and Development Goodwill And In Process Research And Development Policy [Text Block] Impairment of Long-Lived Assets Including Goodwill and Other Acquired Intangible Assets Impairment Or Disposal Of Long Lived Assets Including Intangible Assets Policy Policy [Text Block] Cost Method Investment Cost Method Investments Policy Revenue Recognition Revenue Recognition Policy [Text Block] Cost of Revenue Cost Of Sales Policy [Text Block] Warranty Costs Standard Product Warranty Policy Research and Development Research And Development Expense Policy