Consolidated Condensed Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 24, 2017
Income Statement [Abstract]
Net sales	$ 254,483	$ 320,735
Cost of sales	129,924	159,019
Gross profit	124,559	161,716
Operating expenses
Research and development	97,932	83,557
Selling, general and administrative	32,784	30,859
Total operating expenses	130,716	114,416
Income (loss) from operations	(6,157)	47,300
Interest income	1,706	929
Interest expense	(259)	(335)
Other income (expense)	210	(19)
Income (loss) before income taxes	(4,500)	47,875
Provision (benefit) for income taxes	(228)	4,963
Net income (loss)	$ (4,272)	$ 42,912
Basic earnings (loss) per share (in dollars per share)	$ (0.07)	$ 0.67
Diluted earnings (loss) per share (in dollars per share)	$ (0.07)	$ 0.64
Basic weighted average common shares outstanding (in shares)	61,462	64,097
Diluted weighted average common shares outstanding (in shares)	61,462	67,160