Goodwill and Acquisition-Related Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 01, 2017	Apr. 01, 2017
Gross and net amounts of goodwill and of acquisition-related intangibles
Goodwill	$ 161,287	$ 161,287
Total acquisition-related intangibles, gross	126,747	126,747
Less accumulated amortization	(123,876)	(123,171)
Total	2,871	3,576
Core Technology [Member]
Gross and net amounts of goodwill and of acquisition-related intangibles
Total acquisition-related intangibles, gross	79,981	79,981
Less accumulated amortization	(77,197)	(76,512)
Total	$ 2,784	3,469
Weighted-Average Amortization Life	5 years 7 months
Other Intangibles [Member]
Gross and net amounts of goodwill and of acquisition-related intangibles
Total acquisition-related intangibles, gross	$ 46,766	46,766
Less accumulated amortization	(46,679)	(46,659)
Total	$ 87	$ 107
Weighted-Average Amortization Life	2 years 7 months