Restructuring (Details textual) (USD $)	3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		12 Months Ended	6 Months Ended
	Sep. 30, 2012 Employees	Sep. 30, 2012	Apr. 01, 2012	Sep. 30, 2012 Employee Severance [Member]	Sep. 30, 2012 Facility Closing [Member]	Sep. 30, 2012 Video Processing Product Lines [Member] Employee Retention [Member]	Jul. 01, 2012 Video Processing Product Lines [Member] Employee Retention [Member]	Apr. 01, 2012 Video Processing Product Lines [Member] Employee Retention [Member]	Sep. 30, 2012 Oregon Facility [Member] Employee Retention [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses				$ 2,200,000		$ 200,000	$ 800,000	$ 3,600,000
Restructuring and Related Cost, Number of Positions Eliminated	51
Restructuring Reserve	1,724,000	1,724,000	5,198,000		400,000	1,400,000
Restructuring Reserve, Settled with Cash		$ 6,696,000			$ 100,000	$ 4,600,000			$ 1,000,000