Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Apr. 30, 2015	Apr. 30, 2014
Income Statement [Abstract]
Revenue	$ 71,013us-gaap_Revenues	$ 40,921us-gaap_Revenues
Cost of revenue	25,095us-gaap_CostOfRevenue	15,325us-gaap_CostOfRevenue
Gross profit	45,918us-gaap_GrossProfit	25,596us-gaap_GrossProfit
Operating expenses:
Research and development	16,583us-gaap_ResearchAndDevelopmentExpense	12,914us-gaap_ResearchAndDevelopmentExpense
Selling, general and administrative	9,010	6,755
Total operating expenses	25,593us-gaap_OperatingExpenses	19,669us-gaap_OperatingExpenses
Income from operations	20,325us-gaap_OperatingIncomeLoss	5,927us-gaap_OperatingIncomeLoss
Other income	27us-gaap_NonoperatingIncomeExpense	49us-gaap_NonoperatingIncomeExpense
Income before income taxes	20,352	5,976
Provision for income taxes	1,498us-gaap_IncomeTaxExpenseBenefit	716us-gaap_IncomeTaxExpenseBenefit
Net income	$ 18,854us-gaap_NetIncomeLoss	$ 5,260us-gaap_NetIncomeLoss
Net income per share attributable to ordinary shareholders:
Basic	$ 0.61us-gaap_EarningsPerShareBasic	$ 0.18us-gaap_EarningsPerShareBasic
Diluted	$ 0.56us-gaap_EarningsPerShareDiluted	$ 0.17us-gaap_EarningsPerShareDiluted
Weighted-average shares used to compute net income per share attributable to ordinary shareholders:
Basic	31,099,081	28,976,339
Diluted	33,472,309	31,763,993

The aggregate cost of goods produced and sold and services rendered during the reporting period.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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The net result for the period of deducting operating expenses from operating revenues.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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