Stock-based Compensation (Summary of Stock Option Activity under Service Based Plans) (Details) - Service-based Stock Option - USD ($) $ / shares in Units, $ in Millions		6 Months Ended	12 Months Ended
		Feb. 01, 2020	Aug. 03, 2019
Number of Shares
Options outstanding – August 3, 2019 (in shares)		850,400
Granted (in shares)		274,600
Exercised (in shares)		0
Canceled/Forfeited (in shares)		(378,300)
Options outstanding – February 1, 2020 (in shares)		746,700	850,400
Options vested and expected to vest at February 1, 2020 (in shares)	[1]	707,400
Options exercisable at February 1, 2020 (in shares)		402,300
Weighted- Average Exercise Price
Options outstanding – August 3, 2019 (in dollars per share)		$ 156.00
Granted (in dollars per share)		5.13
Exercised (in dollars per share)		0
Canceled/Forfeited (in dollars per share)		185.56
Options outstanding – February 1, 2020 (in dollars per share)		85.54	$ 156.00
Options vested and expected to vest at February 1, 2020 (in dollars per share)	[1]	89.98
Options exercisable at February 1, 2020 (in dollars per share)		$ 139.70
Weighted- Average Remaining Contractual Terms
Options outstanding, weighted-average remaining contractual terms		4 years 10 months 7 days	4 years 1 month
Options vested and expected to vest at February 1, 2020, weighted-average remaining contractual terms	[1]	4 years 10 months 7 days
Options exercisable at February 1, 2020, weighted-average remaining contractual terms		3 years 9 months
Aggregate Intrinsic Value
Options outstanding, aggregate intrinsic value	[2]	$ 0.0	$ 0.0
Options vested and expected to vest at February 1, 2020, aggregate intrinsic value	[1],[2]	0.0
Options exercisable at February 1, 2020, aggregate intrinsic value	[2]	$ 0.0

[1] The number of options expected to vest takes into consideration estimated expected forfeitures.

[2] The intrinsic value is the amount by which the market price at the end of the period of the underlying share of stock exceeds the exercise price of the stock option.