Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Cash flows from operating activities:
Net loss	$ (47,297)	$ (31,811)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	8,868	8,231
Amortization (accretion) of premium (discount) on marketable debt securities, net	348	(879)
Stock-based compensation	51,407	49,968
Deferred income taxes	(63)	267
Other non-cash items, net	(94)	87
Changes in operating assets and liabilities:
Accounts receivable	(5,624)	4,603
Inventories	(741)	(1,593)
Prepaid expenses and other current assets	238	857
Other assets	683	(2,974)
Accounts payable	(297)	5,896
Accrued and other current liabilities	9,887	3,658
Income taxes payable	1,020	(38)
Deferred revenue	477	16
Lease Liabilities	(1,656)	(2,238)
Other long-term liabilities	1,160	1,234
Net cash provided by operating activities	18,316	35,284
Cash flows from investing activities:
Purchase of investments	(175,265)	(160,988)
Sales of investments	57,936	72,773
Maturities of investments	92,897	105,995
Purchase of property and equipment	(1,529)	(1,425)
Net cash provided by (used in) investing activities	(25,961)	16,355
Cash flows from financing activities:
Stock repurchase	(1,000)
Proceeds from exercise of stock options and employee stock purchase plan	6,504	9,552
Payment for intangible asset	(3,753)	(2,930)
Net cash provided by financing activities	1,751	6,622
Net increase (decrease) in cash, cash equivalents and restricted cash	(5,894)	58,261
Cash, cash equivalents and restricted cash at beginning of period	231,412	194,058
Cash, cash equivalents and restricted cash at end of period	225,518	252,319
Supplemental disclosure of cash flow information:
Cash paid for income taxes	937	1,664
Supplemental disclosure of noncash investing and financing activities:
Unpaid liabilities related to intangible and fixed assets additions	$ 3,656	$ 618