CONSOLIDATED STATEMENT OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Cumulative effect of accounting change	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital Cumulative effect of accounting change	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Accumulated Deficit Cumulative effect of accounting change
Common stock, beginning balance (in shares) at Jan. 31, 2019			54,321,810
Beginning balance at Jan. 31, 2019	$ 264,566	$ (4,103)	$ 54	$ 754,612		$ (1,319)	$ (174)	$ (488,607)	$ (4,103)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises (in shares)			2,163,361
Stock option exercises	16,777		$ 3	16,774
Repurchase of early exercised options (in shares)			(5,677)
Vesting of early exercised stock options	296			296
Vesting of restricted stock units (in shares)			748,061
Stock-based compensation	75,776			75,776
Issuance of common stock under the Employee Stock Purchase Plan (in shares)			154,988
Issuance of common stock under the Employee Stock Purchase Plan	13,420			13,420
Equity component of the convertible senior notes	288,998			288,998
Purchase of capped calls	(93,820)			(93,820)
Impact from 2024 Notes Partial Repurchase	(303,929)			(303,929)
Unrealized gain (loss) on available-for-sale securities	91						91
Foreign currency translation adjustment	308						308
Net loss	(175,522)							(175,522)
Common stock, ending balance (in shares) at Jan. 31, 2020			57,382,543
Ending balance at Jan. 31, 2020	$ 82,858	(227)	$ 57	752,127		(1,319)	225	(668,232)	(227)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises (in shares)	2,218,661		2,218,661
Stock option exercises	$ 16,986		$ 3	16,983
Repurchase of early exercised options (in shares)			(960)
Vesting of early exercised stock options	100			100
Vesting of restricted stock units (in shares)			1,163,259
Vesting of restricted stock units	1		$ 1
Stock-based compensation	149,313			149,313
Issuance of common stock under the Employee Stock Purchase Plan (in shares)			134,930
Issuance of common stock under the Employee Stock Purchase Plan	18,523			18,523
Conversion of redeemable convertible preferred stock to common stock (in shares)			18
Temporary equity reclassification	(4,714)			(4,714)
Unrealized gain (loss) on available-for-sale securities	(30)						(30)
Foreign currency translation adjustment	(899)						(899)
Net loss	(266,944)							(266,944)
Common stock, ending balance (in shares) at Jan. 31, 2021			60,898,451
Ending balance at Jan. 31, 2021	$ (5,033)	$ (256,746)	$ 61	932,332	$ (309,381)	(1,319)	(704)	(935,403)	$ 52,635
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises (in shares)	1,279,669		1,279,669
Stock option exercises	$ 9,665		$ 1	9,664
Vesting of early exercised stock options	10			10
Vesting of restricted stock units (in shares)			1,437,133
Vesting of restricted stock units	1		$ 1
Stock-based compensation	251,982			251,982
Issuance of common stock under the Employee Stock Purchase Plan (in shares)			85,401
Issuance of common stock under the Employee Stock Purchase Plan	25,210			25,210
Issuance of common stock, net of issuance costs (in shares)			2,500,000
Issuance of common stock, net of issuance costs	889,184		$ 3	889,181
Conversion of redeemable convertible preferred stock to common stock (in shares)			1,243,706
Conversion of convertible senior notes	61,517		$ 1	61,516
Unrealized gain (loss) on available-for-sale securities	(3,464)						(3,464)
Foreign currency translation adjustment	1,240						1,240
Net loss	(306,866)							(306,866)
Common stock, ending balance (in shares) at Jan. 31, 2022			67,444,360
Ending balance at Jan. 31, 2022	$ 666,700		$ 67	$ 1,860,514		$ (1,319)	$ (2,928)	$ (1,189,634)