CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance (in shares) at Jan. 31, 2020		278,731,143
Beginning balance at Jan. 31, 2020	$ 833,943	$ 277	$ 832,705	$ 809	$ 152
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon follow-on public offering, net of underwriting discounts and commissions and other offering costs (in shares)		5,882,353
Issuance of common stock upon follow-on public offering, net of underwriting discounts and commissions and other offering costs	1,979,544	$ 6	1,979,538
Issuance of common stock upon exercise of stock options (in shares)		7,378,477
Issuance of common stock upon exercise of stock options	29,107	$ 7	29,100
Issuance of common stock upon release of restricted stock units (in shares)		633,697
Issuance of common stock upon release of restricted stock units	1	$ 1
Charitable donation of common stock	23,312		23,312
Issuance of common stock for employee stock purchase plan (in shares)		923,553
Issuance of common stock for employee stock purchase plan	38,433	$ 1	38,432
Stock-based compensation expense	284,081		284,081
Other comprehensive income	30			30
Net income	672,316				672,316
Ending balance (in shares) at Jan. 31, 2021		293,549,223
Ending balance at Jan. 31, 2021	3,860,767	$ 292	3,187,168	839	672,468
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		2,881,485
Issuance of common stock upon exercise of stock options	14,810	$ 4	14,806
Issuance of common stock upon release of restricted stock units (in shares)		1,768,702
Issuance of common stock upon release of restricted stock units	2	$ 2
Issuance of common stock for employee stock purchase plan (in shares)		838,395
Issuance of common stock for employee stock purchase plan	59,331	$ 1	59,330
Stock-based compensation expense	488,210		488,210
Other comprehensive income	(18,741)			(18,741)
Net income	1,375,639				1,375,639
Ending balance (in shares) at Jan. 31, 2022		299,037,805
Ending balance at Jan. 31, 2022	$ 5,780,018	$ 299	3,749,514	(17,902)	2,048,107
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	1,299,758	1,299,758
Issuance of common stock upon exercise of stock options	$ 8,815	$ 1	8,814
Issuance of common stock upon release of restricted stock units (in shares)		3,977,915
Issuance of common stock upon release of restricted stock units	0	$ 4	(4)
Repurchase of common stock (in shares)		(11,170,907)
Repurchase of common stock	(1,000,003)	$ (11)	(999,992)
Issuance of common stock for employee stock purchase plan (in shares)		678,279
Issuance of common stock for employee stock purchase plan	53,710	$ 1	53,709
Stock-based compensation expense	1,292,839		1,292,839
Other comprehensive income	(32,483)			(32,483)
Net income	103,711				103,711
Ending balance (in shares) at Jan. 31, 2023		293,822,850
Ending balance at Jan. 31, 2023	$ 6,206,607	$ 294	$ 4,104,880	$ (50,385)	$ 2,151,818