Segment and Geographic Information - Revenue by Major Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 95,977	$ 101,484	$ 102,715	$ 98,623	$ 95,266	$ 91,971	$ 94,137	$ 104,587	$ 398,799	$ 385,961	$ 427,054
Total revenue, percent									100.00%	100.00%	100.00%
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 38,585	$ 48,315	$ 51,752
Total revenue, percent									10.00%	13.00%	12.00%
Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 360,214	$ 337,646	$ 375,302
Total revenue, percent									90.00%	87.00%	88.00%
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 202,983	$ 193,590	$ 186,865
Total revenue, percent									51.00%	50.00%	44.00%
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 45,546	$ 44,547	$ 59,835
Total revenue, percent									11.00%	12.00%	14.00%
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 44,033	$ 42,286	$ 49,080
Total revenue, percent									11.00%	11.00%	12.00%
Taiwan
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 16,124	$ 14,846	$ 31,322
Total revenue, percent									4.00%	4.00%	7.00%
Other Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 34,979	$ 26,916	$ 37,826
Total revenue, percent									9.00%	7.00%	9.00%
Other Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 16,549	$ 15,461	$ 10,374
Total revenue, percent									4.00%	4.00%	3.00%