CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				9 Months Ended
	Oct. 02, 2020		Sep. 27, 2019		Oct. 02, 2020		Sep. 27, 2019
Income Statement [Abstract]
Revenue	$ 142,929		$ 154,066		$ 443,125		$ 466,397
Cost of revenue	83,824		90,012		260,873		270,272
Gross profit	59,105		64,054		182,252		196,125
Operating expenses:
Research and development and engineering	15,231		13,811		45,005		41,196
Selling, general and administrative	26,788		27,926		82,451		88,977
Amortization of purchased intangible assets	3,533		3,970		10,388		11,740
Restructuring, acquisition, and related costs	1,687		5,546		5,591		11,913
Total operating expenses	47,239		51,253		143,435		153,826
Operating income	11,866		12,801		38,817		42,299
Interest income (expense), net	(1,698)		(2,153)		(5,077)		(6,357)
Foreign exchange transaction gains (losses), net	(136)		387		(164)		455
Other income (expense), net	(14)		(48)		47		(186)
Income before income taxes	10,018		10,987		33,623		36,211
Income tax provision	1,760		2,064		1,758		4,655
Consolidated net income	$ 8,258	[1]	$ 8,923	[2]	$ 31,865	[1]	$ 31,556	[2]
Earnings per common share (Note 5):
Basic	$ 0.23	[1]	$ 0.25	[2]	$ 0.91	[1]	$ 0.90	[2]
Diluted	$ 0.23	[1]	$ 0.25	[2]	$ 0.89	[1]	$ 0.89	[2]
Weighted average common shares outstanding—basic	35,142	[1]	35,074	[2]	35,144	[1]	35,012	[2]
Weighted average common shares outstanding—diluted	35,688	[1]	35,585	[2]	35,609	[1]	35,523	[2]

[1] 73 thousand non-GAAP EPS performance-based restricted stock units granted to certain members of the executive management team and 213 thousand shares of restricted stock issued to the former Laser Quantum non-controlling interest shareholders are considered contingently issuable shares and were excluded from the calculation of the denominator as the contingent conditions had not been met as of October 2, 2020.

[2] 47 thousand non-GAAP EPS performance-based restricted stock units granted to certain members of the executive management team and 213 thousand shares of restricted stock issued to the former Laser Quantum non-controlling interest shareholders were considered contingently issuable shares and were excluded from the calculation of the denominator as the contingent conditions had not been met as of September 27, 2019.