Equity Incentive Plans - Restricted Stock Units (Details) - Unvested RSUs and PRSUs - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 02, 2020	Jul. 31, 2019	Aug. 02, 2020	Jul. 31, 2019	Feb. 02, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, target (as a percent)	100.00%
Number of Restricted Stock Units Outstanding
Unvested, Beginning balance (in shares)			25,434,597
Granted (in shares)	1,451,896		14,461,995
Vested (in shares)			(5,454,940)
Forfeited (in shares)			(1,643,740)
Unvested, Ending balance (in shares)	32,797,912		32,797,912
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)			$ 18.72
Granted (in dollars per share)			11.27
Vested (in dollars per share)			16.93
Forfeited (in dollars per share)			17.34
Ending balance (in dollars per share)	$ 15.80		$ 15.80
Aggregate Intrinsic Value	$ 585,770		$ 585,770		$ 452,736
Share-based compensation expense	50,100	$ 40,400	96,900	$ 77,700
Compensation not yet recognized	$ 472,500		$ 472,500
Compensation cost (in years)			2 years 10 months 24 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, target (as a percent)	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, target (as a percent)	125.00%