Consolidated Condensed Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jun. 27, 2020	Jun. 29, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 18,209	$ 4,618
Other comprehensive income (loss), before tax
Foreign currency translation gain	1,014	24
Unrealized gain on marketable securities	9,488	2,115
Cumulative effect of adoption of ASU 2018-02	0	(257)
Provision for income taxes	(1,992)	(444)
Comprehensive income	$ 26,719	$ 6,056
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201802Member