Consolidated Condensed Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 28, 2019	Dec. 29, 2018
Income Statement [Abstract]
Net sales	$ 374,668	$ 324,295	$ 1,001,833	$ 945,083
Cost of sales	177,163	161,115	473,901	472,225
Gross profit	197,505	163,180	527,932	472,858
Operating expenses
Research and development	88,713	88,575	265,782	282,888
Selling, general and administrative	36,113	30,364	98,651	96,308
Total operating expenses	124,826	118,939	364,433	379,196
Income from operations	72,679	44,241	163,499	93,662
Interest income	2,651	1,999	7,725	5,510
Interest expense	(259)	(259)	(798)	(798)
U.K. pension settlement	0	(13,768)	0	(13,768)
Other income (expense)	(563)	101	(1,509)	(67)
Income before income taxes	74,508	32,314	168,917	84,539
Provision for income taxes	5,996	2,381	19,577	705
Net income	$ 68,512	$ 29,933	$ 149,340	$ 83,834
Basic earnings per share (in dollars per share)	$ 1.18	$ 0.50	$ 2.56	$ 1.39
Diluted earnings per share (in dollars per share)	$ 1.13	$ 0.49	$ 2.47	$ 1.35
Basic weighted average common shares outstanding (in shares)	58,188	59,511	58,247	60,482
Diluted weighted average common shares outstanding (in shares)	60,492	60,783	60,395	62,076