Balance Sheet Components (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	May 31, 2013
Inventories
Raw materials	$ 2,999	$ 2,225
Work in process	4,065	3,066
Finished goods	5,952	4,220
Total	13,016	9,511
Property, Plant and Equipment
Total property, plant and equipment	86,706	87,729
Less: Accumulated depreciation, amortization and impairment	(40,064)	(45,825)
Property, plant and equipment, net	46,642	41,904
Impairment charge
Impairment of long-lived assets	7,507
Buildings and improvements
Property, Plant and Equipment
Total property, plant and equipment	14,501	14,501
Machinery and equipment
Property, Plant and Equipment
Total property, plant and equipment	64,267	64,898
Leasehold improvements
Property, Plant and Equipment
Total property, plant and equipment	3,143	3,143
Other equipment
Property, Plant and Equipment
Total property, plant and equipment	2,249	2,182
Construction in progress
Property, Plant and Equipment
Total property, plant and equipment	$ 2,546	$ 3,005