CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Cash flows from operating activities:
Net income	$ 4,741	$ 2,602
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment	194	176
Loss on disposal of long-lived assets	3
Amortization of other intangible assets		135
Stock-based compensation	1,606	943
Net excess income tax benefits associated with stock-based compensation	(91)
Change in value of warrants		(10)
Changes in operating assets and liabilities:
Accounts receivable	(3,314)	555
Inventories	(407)	(830)
Prepaid expenses and other current assets	521	110
Deferred tax assets	(139)	1
Other assets	(73)	22
Accounts payable	3,313	(808)
Accrued liabilities	(3,687)	319
Income taxes payable	(24)	205
Deferred revenue	573	(2,640)
Net cash provided by operating activities	3,216	780
Cash flows from investing activities:
Restricted Cash		(8)
Purchase of property and equipment	(579)	(147)
Net cash used in investing activities	(579)	(155)
Cash flows from financing activities:
Proceeds from exercise of stock options, warrants, and employee stock purchase plan withholding, net of repurchase of stock options	1,080	125
Payment for initial public offering cost	(25)
Net excess income tax benefits associated with stock-based compensation	91
Net cash provided by financing activities	1,146	125
Net increase in cash and cash equivalents	3,783	750
Cash and cash equivalents at beginning of period	100,494	58,944
Cash and cash equivalents at end of period	104,277	59,694
Supplemental disclosure of cash flow information:
Cash paid for income taxes	157	99
Supplemental disclosure of noncash investing activities:
Increase in accrued liabilities related to non-monetary assets purchases	$ 181	$ 48