Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012
Cash flows from operating activities:
Net income	$ 20,121	$ 14,545
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment	789	545
Loss on disposal of long-lived assets	4	2
Amortization of other intangible assets		270
Stock-based compensation	5,660	3,441
Net excess income tax benefits associated with stock-based compensation	(513)
Change in value of warrants		(149)
Changes in operating assets and liabilities:
Accounts receivable	(5,296)	(8,758)
Inventories	(4,092)	(2,355)
Prepaid expenses and other current assets	362	(290)
Deferred tax assets	(20)	(472)
Other assets	9	17
Accounts payable	7,088	2,435
Accrued liabilities	(1,588)	4,026
Income taxes payable	304	585
Deferred revenue	101	(4,790)
Net cash provided by operating activities	22,929	9,052
Cash flows from investing activities:
Restricted Cash		247
Net proceeds from disposal of fixed assets	13
Purchase of property and equipment	(1,384)	(997)
Net cash used in investing activities	(1,371)	(750)
Cash flows from financing activities:
Proceeds from exercise of stock options, warrants, and employee stock purchase plan withholding, net of repurchase of stock options	5,511	933
Payment for initial public offering cost	(25)	(727)
Proceeds from initial public offering, net of underwriting discounts and commissions		27,368
Net excess income tax benefits associated with stock-based compensation	513
Net cash provided by financing activities	5,999	27,574
Net increase in cash and cash equivalents	27,557	35,876
Cash and cash equivalents at beginning of period	100,494	58,944
Cash and cash equivalents at end of period	128,051	94,820
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,394	1,897
Supplemental disclosure of noncash investing activities:
Increase in accrued liabilities related to non-monetary assets purchases	33	147
Supplemental disclosure of noncash financing activities:
Increase in accrued liabilities related to non-monetary financing activities		1,245
Conversion of convertible preference shares to ordinary shares		50,900
Conversion of convertible preference share warrants to ordinary share warrants		$ 110