Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020
Cash flows from operating activities:
Net loss	$ (17,218)	$ (47,297)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	9,139	8,868
Amortization (accretion) of premium (discount) on marketable debt securities, net	1,034	348
Stock-based compensation	60,267	51,407
Deferred income taxes	(553)	(63)
Other non-cash items, net	(517)	(94)
Changes in operating assets and liabilities:
Accounts receivable	(19,802)	(5,624)
Inventories	(20,958)	(741)
Prepaid expenses and other current assets	(275)	238
Other non-current assets	878	683
Accounts payable	5,947	(297)
Accrued and other current liabilities	2,359	9,887
Income taxes payable	396	1,020
Deferred revenue	(57)	477
Operating lease liabilities	(2,681)	(1,656)
Other long-term liabilities	265	1,160
Net cash provided by operating activities	18,224	18,316
Cash flows from investing activities:
Purchase of investments	(118,726)	(175,265)
Sales of investments	208,132	57,936
Maturities of investments	107,760	92,897
Purchase of tangible and intangible assets	(6,235)	(1,529)
Net cash provided by (used in) investing activities	190,931	(25,961)
Cash flows from financing activities:
Stock repurchase	0	(1,000)
Proceeds from exercise of stock options and employee stock purchase plan	11,127	6,504
Payment for intangible assets	(3,796)	(3,753)
Net cash provided by financing activities	7,331	1,751
Net increase (decrease) in cash, cash equivalents and restricted cash	216,486	(5,894)
Cash, cash equivalents and restricted cash at beginning of period	241,284	231,412
Cash, cash equivalents and restricted cash at end of period	457,770	225,518
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,294	937
Supplemental disclosure of noncash investing and financing activities:
Unpaid liabilities related to tangible and intangible assets additions	$ 1,346	$ 3,656