Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Income Statement [Abstract]
Sales	$ 290,213	$ 228,261	$ 605,055	$ 432,855
Cost of goods sold	244,148	184,890	510,186	351,989
Gross profit	46,065	43,371	94,869	80,866
Operating expenses:
Research and development	2,915	2,774	5,944	5,680
Sales and marketing	3,630	3,351	7,435	6,402
General and administrative	16,856	12,841	31,918	24,606
Total operating expenses	23,401	18,966	45,297	36,688
Income from operations	22,664	24,405	49,572	44,178
Interest and other income (expense), net	(809)	(1,120)	(483)	(2,058)
Income before provision for income taxes	21,855	23,285	49,089	42,120
Income tax provision	2,895	3,106	5,388	7,600
Net income	$ 18,960	$ 20,179	$ 43,701	$ 34,520
Net income per share:
Basic	$ 0.49	$ 0.60	$ 1.16	$ 1.04
Diluted	$ 0.48	$ 0.59	$ 1.14	$ 1.01
Shares used in computing net income per share:
Basic	38,802	33,433	37,763	33,247
Diluted	39,297	34,064	38,418	34,017