Segment Reporting (Details) (USD $)	3 Months Ended
	Oct. 31, 2012		Oct. 29, 2011
United States [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	$ 24,810,000	[1]	$ 28,430,000	[2]
Gross Long-Lived Assets	29,899,000	[1]	26,470,000	[2]
Foreign Countries [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	12,012,000	[1]	13,882,000	[2]
Gross Long-Lived Assets	5,440,000	[1]	5,187,000	[2]
Peru [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	3,500,000		3,600,000
Brazil [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	4,100,000		4,100,000
Chile [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	$ 2,500,000		$ 2,500,000

[1] Revenue is attributed to countries based on the location of the customers. Revenues in the most significant foreign countries include $3.5 million in Peru, $4.1 million in Brazil and $2.5 million in Chile.

[2] Revenue is attributed to countries based on the location of the customers. Revenues in the most significant foreign countries include $3.6 million in Peru, $4.1 million in Brazil and $2.5 million in Chile.