Goodwill and Intangible Assets (Details Textual) (USD $)	12 Months Ended				3 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2013 Broadcast Servers and Storage Business Unit [Member]	Apr. 30, 2012 Media Services [Member]
Goodwill, Impairment Loss					$ 17,000,000
Goodwill	45,103,000	44,414,000	64,679,000	600,000
Amortization of intangibles	3,966,000	3,784,000	3,073,000
Amortization Expense Charged To Cost Of Product Revenues	2,400,000	2,500,000	2,000,000
Amortization Expense Charged To Operating Expense	4,000,000	3,800,000	3,100,000
Intangible assets, net	$ 17,514,000	$ 22,432,000