CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 13,539	$ 6,974	$ 29,506	$ (19,201)
Other comprehensive income (loss):
Unrealized gain related to marketable securities, net of tax	0	14	42	16
Reclassification adjustment for gains related to marketable securities included in Other (expense) income, net of tax	0	(17)	(53)	(18)
Translation adjustment, net of tax	(93)	(584)	(7)	(1,124)
Comprehensive income (loss)	$ 13,446	$ 6,387	$ 29,488	$ (20,327)