Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Cash flows from operating activities:
Net loss	$ (15,463)	$ (17,311)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	2,872	2,708
Amortization/accretion of marketable debt securities	10	(378)
Stock-based compensation	16,036	16,460
Deferred income taxes	457	21
Other non-cash items, net	(38)	142
Changes in operating assets and liabilities:
Accounts receivable	(2,197)	(245)
Inventories	1,014	617
Prepaid expenses and other current assets	193	1,007
Other assets	351	60
Accounts payable	5,679	3,254
Accrued liabilities	(1,343)	(454)
Income taxes payable	58	(311)
Deferred revenue	101	36
Lease Liabilities	(689)	(727)
Other long-term liabilities	598	453
Net cash provided by operating activities	7,639	5,332
Cash flows from investing activities:
Purchase of investments	(49,077)	(35,583)
Sales of investments	13,601	10,023
Maturities of investments	33,740	29,195
Purchase of property and equipment	(428)	(513)
Net cash provided by (used in) investing activities	(2,164)	3,122
Cash flows from financing activities:
Stock repurchase	(1,000)
Proceeds from exercise of stock options and employee stock purchase plan	1,912	2,938
Payment for intangible asset	(1,205)	(995)
Net cash provided by (used in) financing activities	(293)	1,943
Net increase in cash, cash equivalents and restricted cash	5,182	10,397
Cash, cash equivalents and restricted cash at beginning of period	231,412	194,058
Cash, cash equivalents and restricted cash at end of period	236,594	204,455
Supplemental disclosure of cash flow information:
Cash paid for income taxes	370	797
Supplemental disclosure of noncash investing and financing activities:
Unpaid liabilities related to intangible and fixed assets additions	$ 67	$ 372