Segment, Geographic, Product and Significant Customer Information - Revenue Net (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017 USD ($)	Jun. 25, 2016 USD ($)	Jul. 01, 2017 USD ($) segment	Jun. 25, 2016 USD ($)
Revenues From External Customers And Long Lived Assets [Line Items]
Number of operating segments | segment			1
Net revenues:
Total net revenues	$ 64,427	$ 55,767	$ 123,741	$ 103,256
South Korea [Member]
Net revenues:
Total net revenues	31,500	4,468	50,119	12,904
Japan [Member]
Net revenues:
Total net revenues	9,267	6,379	12,620	13,567
United States [Member]
Net revenues:
Total net revenues	8,297	8,904	21,870	16,095
China [Member]
Net revenues:
Total net revenues	7,330	13,009	14,017	19,515
Taiwan [Member]
Net revenues:
Total net revenues	4,878	5,151	16,711	10,629
Singapore [Member]
Net revenues:
Total net revenues	963	16,617	2,454	26,519
Other [Member]
Net revenues:
Total net revenues	$ 2,192	$ 1,239	$ 5,950	$ 4,027