Stock-Based Compensation - Assumptions (Details) - 2016 Equity Plan	12 Months Ended
	Jan. 25, 2020	Jan. 26, 2019	Jan. 27, 2018
Assumptions:
Weighted-average expected volatility (as a percent)	60.90%	58.60%	57.70%
Weighted-average expected term (in years)	4 years 2 months 12 days	5 years	4 years
Weighted-average risk-free interest rate (as a percent)	2.10%	2.80%	2.00%