Segment, Geographic, Product and Significant Customer Information - Revenue Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Net revenues:
Total net revenues	$ 82,313	$ 59,314
South Korea [Member]
Net revenues:
Total net revenues	37,818	18,619
Japan [Member]
Net revenues:
Total net revenues	13,379	3,353
United States [Member]
Net revenues:
Total net revenues	6,738	13,573
China [Member]
Net revenues:
Total net revenues	8,042	6,687
Taiwan [Member]
Net revenues:
Total net revenues	1,060	11,833
Singapore [Member]
Net revenues:
Total net revenues	12,155	1,491
Other [Member]
Net revenues:
Total net revenues	$ 3,121	$ 3,758