Net Loss per Share Attributable to Common Stockholders - Shares Excluded (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Aug. 02, 2020	Jul. 31, 2019	Aug. 02, 2020	Jul. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	81,775	82,773	81,095	82,976
Stock options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	23,329	31,739	24,482	32,852
Unvested RSUs and PRSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	33,286	25,513	31,216	24,743
Restricted stock subject to repurchase
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	1,236	2,917	1,473	2,777
Shares related to convertible senior notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	21,884	21,884	21,884	21,884
Shares issuable pursuant to the ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share, amount (in shares)	2,040	720	2,040	720