Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Cash flows from operating activities:
Net loss	$ (30,219)	$ (27,502)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,786	5,439
Amortization/accretion of marketable debt securities	88	(696)
Stock-based compensation	32,430	32,660
Deferred income taxes	188	170
Other non-cash items, net	(72)	87
Changes in operating assets and liabilities:
Accounts receivable	(4,788)	(1,728)
Inventories	(936)	876
Prepaid expenses and other current assets	1,472	1,541
Other assets	329	(2,834)
Accounts payable	(1,217)	6,111
Accrued liabilities	2,144	(288)
Income taxes payable	(180)	90
Deferred revenue	699	24
Lease Liabilities	(1,031)	(1,454)
Other long-term liabilities	529	923
Net cash provided by operating activities	5,222	13,419
Cash flows from investing activities:
Purchase of investments	(109,161)	(91,143)
Sales of investments	44,044	32,573
Maturities of investments	49,227	71,395
Purchase of property and equipment	(665)	(954)
Net cash provided by (used in) investing activities	(16,555)	11,871
Cash flows from financing activities:
Stock repurchase	(1,000)
Proceeds from exercise of stock options and employee stock purchase plan	3,866	5,429
Payment for intangible asset	(2,288)	(2,075)
Net cash provided by financing activities	578	3,354
Net increase (decrease) in cash, cash equivalents and restricted cash	(10,755)	28,644
Cash, cash equivalents and restricted cash at beginning of period	231,412	194,058
Cash, cash equivalents and restricted cash at end of period	220,657	222,702
Supplemental disclosure of cash flow information:
Cash paid for income taxes	842	1,283
Supplemental disclosure of noncash investing and financing activities:
Unpaid liabilities related to intangible and fixed assets additions	$ 1,174	$ 347