Note 10. Goodwill and Intangible Assets (Detail) - Purchased Intangible Assets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Apr. 01, 2012
Carrying Amount	$ 51,511	$ 43,778
Accumulated Amoritzation	(38,173)	(34,023)
Net Carrying Amount	13,338	9,755
Existing Technology [Member]
Carrying Amount	42,858	34,848
Accumulated Amoritzation	(30,668)	(27,286)
Net Carrying Amount	12,190	7,562
Patents [Member]
Carrying Amount	3,459	3,736
Accumulated Amoritzation	(3,182)	(2,855)
Net Carrying Amount	277	881
Distributor Relationships [Member]
Carrying Amount	1,264	1,264
Accumulated Amoritzation	(1,219)	(1,119)
Net Carrying Amount	45	145
Customer Relationships [Member]
Carrying Amount	2,905	2,905
Accumulated Amoritzation	(2,079)	(1,751)
Net Carrying Amount	826	1,154
Trade Names [Member]
Carrying Amount	1,025	1,025
Accumulated Amoritzation	(1,025)	(1,012)
Net Carrying Amount		$ 13