Long-Term Incentive Awards (Details) - USD ($)	3 Months Ended			12 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Apr. 30, 2017	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Stock Based Compensation
Stock based compensation expense				$ 6,985,000	$ 4,956,000	$ 3,392,000
LTIP
Stock Based Compensation
Stock based compensation expense				1,889,000	428,000
Fiscal 2019 LTIP | Performance based restricted stock units
Stock Based Compensation
Stock based compensation expense				572,000
Fiscal 2019 LTIP | Performance based restricted stock units | 100% Vested
Stock Based Compensation
Vesting (as a percentage)	100.00%
Fiscal 2019 LTIP | Performance based restricted stock units | 50% Vested
Stock Based Compensation
Vesting (as a percentage)	50.00%
Fiscal 2019 LTIP | Performance based restricted stock units | 200% Vested
Stock Based Compensation
Vesting (as a percentage)	200.00%
Fiscal 2019 LTIP | Performance based restricted stock units | Maximum
Stock Based Compensation
Stock based compensation expense				3,033,000
Fiscal 2018 LTIP | Performance based restricted stock units
Stock Based Compensation
Stock based compensation expense				588,000	269,000
Fiscal 2018 LTIP | Performance based restricted stock units | 100% Vested
Stock Based Compensation
Vesting (as a percentage)			100.00%
Fiscal 2018 LTIP | Performance based restricted stock units | 50% Vested
Stock Based Compensation
Vesting (as a percentage)			50.00%
Fiscal 2018 LTIP | Performance based restricted stock units | 200% Vested
Stock Based Compensation
Vesting (as a percentage)			200.00%
Fiscal 2018 LTIP | Performance based restricted stock units | Maximum
Stock Based Compensation
Stock based compensation expense				2,275,000
Fiscal 2017 LTIP | Performance based restricted stock units
Stock Based Compensation
Stock based compensation expense				$ 301,000	$ 159,000
Issue of fully-vested shares of common stock to settle	14,814
Fiscal 2017 LTIP | Performance based restricted stock units | 100% Vested
Stock Based Compensation
Vesting (as a percentage)		100.00%
Fiscal 2017 LTIP | Performance based restricted stock units | 50% Vested
Stock Based Compensation
Vesting (as a percentage)		50.00%
Fiscal 2017 LTIP | Performance based restricted stock units | 200% Vested
Stock Based Compensation
Vesting (as a percentage)		200.00%