Property and Equipment, Net (Details) (USD $)	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Property and Equipment, Net
Total property and equipment, gross	$ 39,232,000	$ 27,563,000
Less: Accumulated depreciation and amortization	(24,460,000)	(17,644,000)
Total property and equipment, net	14,772,000	9,919,000
Property and Equipment, Net (Textuals) [Abstract]
Total depreciation and amortization expense	7,200,000	5,300,000	4,700,000
Computer equipment [Member]
Property and Equipment, Net
Estimated Useful Lives, Maximum	2
Total property and equipment, gross	13,613,000	7,993,000
Computer software [Member]
Property and Equipment, Net
Estimated Useful Lives, Minimum	2
Estimated Useful Lives, Maximum	5
Total property and equipment, gross	6,134,000	4,558,000
Machinery and equipment [Member]
Property and Equipment, Net
Estimated Useful Lives, Maximum	2
Total property and equipment, gross	13,051,000	10,441,000
Furniture and fixtures [Member]
Property and Equipment, Net
Estimated Useful Lives, Maximum	5
Total property and equipment, gross	3,590,000	2,397,000
Leasehold improvements [Member]
Property and Equipment, Net
Estimated Useful Lives, Minimum	1
Estimated Useful Lives, Maximum	6
Total property and equipment, gross	$ 2,844,000	$ 2,174,000