Income Taxes - Schedule of Effective Income Tax Reconciliation Post ASU (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2026	Jan. 31, 2025	Jan. 31, 2024
Amount (in thousands)
Income tax benefit computed at federal statutory rate	$ (275,501)	$ (269,871)	$ (178,337)
State taxes, net of federal benefit	(11,049)	33,910	26,380
Foreign tax effects	6,016
Effect of cross-border tax laws	(12,112)
Tax credits:
Research and development credits	(122,741)	(133,266)	(101,725)
Change in valuation allowance	490,646	363,422	371,767
Nontaxable or nondeductible items:
Section 162(m) - limitation on executive compensation	25,271
Stock-based compensation	(128,731)	(7,667)	(148,600)
Other	6,032
Worldwide changes in unrecognized tax benefits	39,294
Provision for (benefit from) income taxes	$ 17,125	$ 4,113	$ (11,233)
Percent
Federal statutory tax rate	21.00%
State and local income taxes, net of federal income tax effect	0.80%
Foreign tax effects	(0.40%)
Effect of cross-border tax laws	0.90%
Tax credits:
Research and development tax credits	9.40%
Change in valuation allowances	(37.40%)
Nontaxable or nondeductible items:
Section 162(m) - limitation on executive compensation	(1.90%)
Stock-based compensation	9.80%
Other	(0.50%)
Worldwide changes in unrecognized tax benefits	(3.00%)
Provision for income taxes	(1.30%)