Net Loss per Share Attributable to Common Stockholders - Summary of Weighted-average Outstanding Shares Excluded from Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	12 Months Ended
	Feb. 02, 2020	Jan. 31, 2019	Jan. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	81,218	82,582	69,710
Stock options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	31,315	39,928	52,424
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	24,374	19,488	15,496
Shares issuable pursuant to the ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	1,031	2,411	1,544
Early exercised stock options subject to repurchase
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	0	7	246
Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	2,614	2,881	0
Senior Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities (In shares)	21,884	17,867	0