Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Cash flows from operating activities:
Net loss	$ (190,526)	$ (158,441)
Adjustments to reconcile net loss to net cash provided by operating activities:
Stock-based compensation	139,774	89,691
Depreciation, amortization and accretion	23,694	12,336
Amortization of debt discount and issuance costs	47,261	15,653
Amortization of deferred commissions	28,428	20,541
Deferred income taxes	(2,414)	(3,069)
Non-cash charitable contributions	4,662	1,162
Loss on early extinguishment and conversion of debt	2,263	14,572
Other, net	4,515	84
Changes in operating assets and liabilities:
Accounts receivable	(10,547)	(9,393)
Deferred commissions	(51,837)	(36,641)
Prepaid expenses and other assets	(6,794)	(1,518)
Operating lease right-of-use assets	13,979	7,851
Accounts payable	1,377	1,962
Accrued compensation	37,863	17,352
Accrued expenses and other liabilities	2,442	4,017
Operating lease liabilities	(11,750)	(4,128)
Deferred revenue	60,663	58,737
Net cash provided by operating activities	93,053	30,768
Cash flows from investing activities:
Capitalization of internal-use software costs	(3,530)	(2,659)
Purchases of property and equipment	(11,297)	(9,980)
Purchases of securities available for sale and other	(1,845,958)	(321,462)
Proceeds from maturities and redemption of securities available for sale	386,774	244,393
Proceeds from sales of securities available for sale and other	206,129	17,329
Purchases of intangible assets	0	(8,500)
Payments for business acquisition, net of cash acquired	0	(44,223)
Net cash used in investing activities	(1,267,882)	(125,102)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net of issuance costs	1,134,841	1,040,760
Payments for repurchases of convertible senior notes	(447)	(224,414)
Proceeds from hedges related to convertible senior notes	195,046	405,851
Payments for warrants related to convertible senior notes	(175,399)	(358,622)
Purchases of capped calls related to convertible senior notes	(133,975)	(74,094)
Proceeds from stock option exercises	33,570	36,371
Proceeds from shares issued in connection with employee stock purchase plan	12,821	9,005
Other, net	0	(126)
Net cash provided by financing activities	1,066,457	834,731
Effects of changes in foreign currency exchange rates on cash, cash equivalents and restricted cash	121	(241)
Net increase (decrease) in cash, cash equivalents and restricted cash	(108,251)	740,156
Cash, cash equivalents and restricted cash at beginning of period	531,953	311,215
Cash, cash equivalents and restricted cash at end of period	423,702	1,051,371
Cash paid during the period for:
Interest	1,566	862
Income taxes	622	845
Non-cash activities:
Issuance of common stock for repurchases and conversions of convertible senior notes	307,910	380,406
Common stock issued as charitable contribution	4,662	1,162
Operating lease right-of-use assets exchanged for lease liabilities	45,490	14,957
Property and equipment acquired through tenant improvement allowance	4,811	1,682
Impairment of operating lease right-of-use asset	2,587	0
Issuance of common stock for bonus settlement	9,818	2,809
Reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets to the amounts shown in the condensed consolidated statements of cash flows above:
Total cash, cash equivalents and restricted cash	$ 423,702	$ 1,051,371