Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Net revenues:
Total net revenues	$ 67,100	$ 82,313
Costs of net revenues:
Amortization of intangible assets	466	35
Total costs of net revenues	33,312	34,782
Gross profit	33,788	47,531
Operating expenses:
Research and development	12,987	10,202
Selling	9,282	9,024
General and administrative	7,905	7,741
Amortization of intangible assets	289
Total operating expenses	30,463	26,967
Income from operations	3,325	20,564
Other income (expense):
Interest expense, net	(91)	(93)
Other income, net	270	352
Total other income, net	179	259
Income before income taxes	3,504	20,823
Provision for income taxes	531	4,442
Net income	$ 2,973	$ 16,381
Net income per share:
Basic (in dollars per share)	$ 0.12	$ 0.68
Diluted (in dollars per share)	$ 0.12	$ 0.67
Weighted average shares used in per share calculation:
Basic (in shares)	24,474	24,063
Diluted (in shares)	24,783	24,483
Products [Member]
Net revenues:
Total net revenues	$ 53,855	$ 71,019
Costs of net revenues:
Cost of products and service	25,898	28,593
Service [Member]
Net revenues:
Total net revenues	13,245	11,294
Costs of net revenues:
Cost of products and service	$ 6,948	$ 6,154