CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Cash flows from operating activities
Net loss	$ (566,901)	$ (256,301)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	42,685	27,141
Amortization of deferred commissions	61,120	53,882
Amortization of investment premiums (accretion of discounts), net	(944)	(5,645)
Amortization of debt discount and issuance costs	44,738	39,095
Gain on extinguishment of convertible senior notes	(6,952)	0
Repurchase of convertible senior notes attributable to the accreted interest related to debt discount	(22,149)	0
Non-cash operating lease costs	15,759	5,407
Stock-based compensation	313,691	246,076
Disposal of property and equipment	981	0
Deferred income taxes	(644)	(184)
Changes in operating assets and liabilities
Accounts receivable, net	184,261	60,750
Prepaid expenses and other assets	12,493	(109,040)
Deferred commissions	(60,154)	(53,214)
Accounts payable	22,963	5,316
Accrued compensation	(61,378)	(46,215)
Accrued expenses and other liabilities	(1,294)	10,679
Deferred revenue	(102,307)	(71,689)
Net cash used in operating activities	(124,032)	(93,942)
Cash flows from investing activities
Purchases of investments	(87,135)	(539,723)
Maturities of investments	497,725	541,595
Purchases of property and equipment	(25,816)	(26,434)
Capitalized software development costs	(7,133)	0
Other investment activities	2,886	1,250
Net cash provided by (used in) investing activities	374,755	(25,812)
Cash flows from financing activities
Proceeds from the exercise of stock options	2,671	556
Proceeds from employee stock purchase plan	44,214	34,482
Proceeds from the issuance of convertible senior notes, net of issuance costs	1,246,544	0
Purchase of capped calls	(137,379)	0
Partial repurchase of convertible senior notes	(668,929)	0
Taxes paid related to net share settlement of equity awards	(49,228)	(117,693)
Net cash provided by (used in) financing activities	437,893	(82,655)
Effect of exchange rate changes on cash and cash equivalents	626	(1,751)
Net increase (decrease) in cash and cash equivalents	689,242	(204,160)
Cash and cash equivalents at beginning of period	778,653	1,876,165
Cash and cash equivalents at end of period	1,467,895	1,672,005
Supplemental disclosures
Cash paid for income taxes	6,267	15,249
Cash paid for interest	8,557	7,747
Non-cash investing activities
Increase (decrease) in accrued purchases of property and equipment	5,169	274
Vesting of early exercised options	117	0
Costs related to issuance of convertible senior notes included in accrued expenses and other liabilities	$ 1,053	$ 0