COMMON STOCK AND STOCK-BASED COMPENSATION - Allocated Compensation Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jul. 27, 2013	Jul. 28, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	$ 1,166	$ 991
2010 Stock Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	544	631
2010 Stock Plan | RSA's
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	369	366
2010 Stock Plan | RSU's
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	74	132
2010 Stock Plan | Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	101	133
2007 Stock Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	622	360
2007 Stock Plan | RSA's
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	466	233
2007 Stock Plan | Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense	$ 156	$ 127