Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Net revenues:
Total net revenues	$ 324,523	$ 258,621	$ 221,129
Costs of net revenues:
Amortization of intangible assets	284	206	1,454
Total costs of net revenues	140,429	121,920	107,005
Gross profit	184,094	136,701	114,124
Operating expenses:
Research and development	48,188	36,716	31,443
Selling	37,528	30,839	30,181
General and administrative	31,795	26,340	23,381
Amortization of intangible assets	96		24
Total operating expenses	117,607	93,895	85,029
Income from operations	66,487	42,806	29,095
Other income (expense):
Interest income	10	8	35
Interest expense	(331)	(92)	(285)
Other income, net	1,358	576	290
Total other income, net	1,037	492	40
Income before income taxes	67,524	43,298	29,135
Provision for (benefit from) income taxes	9,876	13,096	(14,900)
Net income	$ 57,648	$ 30,202	$ 44,035
Net income per share:
Basic (in dollars per share)	$ 2.39	$ 1.19	$ 1.79
Diluted (in dollars per share)	$ 2.34	$ 1.17	$ 1.75
Weighted average shares used in per share calculation:
Basic (in shares)	24,120	25,334	24,655
Diluted (in shares)	24,600	25,919	25,153
Products [Member]
Net revenues:
Total net revenues	$ 275,286	$ 214,877	$ 185,066
Costs of net revenues:
Cost of products and service	112,834	100,910	85,391
Service [Member]
Net revenues:
Total net revenues	49,237	43,744	36,063
Costs of net revenues:
Cost of products and service	$ 27,311	$ 20,804	$ 20,160