Variable Interest Entities (Details) (USD $)	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Condensed consolidated balance sheets related to VIEs
Cash and cash equivalents	$ 175,142,000	$ 156,524,000	$ 83,292,000
Property, plant and equipment	5,309,000	1,469,000
TOTAL ASSETS	234,724,000	205,252,000
Accounts payable	32,699,000	29,524,000
TOTAL LIABILITIES	115,556,000	104,289,000
Variable Interest Entity, Primary Beneficiary [Member]
Condensed consolidated balance sheets related to VIEs
Cash and cash equivalents	190,000	75,000
Property, plant and equipment	5,309,000	1,469,000
TOTAL ASSETS	5,499,000	1,544,000
Accounts payable	334,000	27,000
Accrued expenses	747,000	224,000
TOTAL LIABILITIES	$ 1,081,000	$ 251,000