Segment, Geographic, Product and Significant Customer Information - Total Net Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Net revenues:
Total net revenues	$ 67,620	$ 88,604	$ 134,720	$ 170,917
United States [Member]
Net revenues:
Total net revenues	9,170	7,392	26,044	14,130
China [Member]
Net revenues:
Total net revenues	25,873	28,333	40,233	36,375
South Korea [Member]
Net revenues:
Total net revenues	13,070	30,980	27,038	68,798
Taiwan [Member]
Net revenues:
Total net revenues	3,650	1,974	14,939	3,034
Japan [Member]
Net revenues:
Total net revenues	4,214	15,017	8,531	28,396
Singapore [Member]
Net revenues:
Total net revenues	8,723	2,380	10,274	14,535
Other [Member]
Net revenues:
Total net revenues	$ 2,920	$ 2,528	$ 7,661	$ 5,649