Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net income (loss)	$ (69,818)	$ 28,156	$ 96,847
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Interest capitalized associated with cloud computing implementation	0	0	(199)
Net accretion on investments	(1,254)	(1,364)	(859)
Loss on extinguishment of debt	241	369	312
Depreciation and amortization	52,487	49,744	46,016
Share-based compensation expense	20,740	17,237	14,918
Inventory related charges	4,977	5,619	6,725
Amortization of debt discounts and issuance costs	8	146	315
Accrued retiree benefits	(1,589)	(540)	(1,589)
Deferred income taxes	(3,722)	(4,774)	(3,504)
Impairment charge related to equity investment	903	0	0
Changes in other assets	(3,831)	(13,286)	(3,230)
Amortization of cloud-based software implementation costs	2,836	2,800	2,060
(Gain) loss from sale of property, plant and equipment	176	(4)	(203)
Changes in other accrued liabilities	(1,309)	(702)	(943)
Operating lease right-of-use assets	5,812	7,656	5,139
Changes in current assets and liabilities:
Customer advances	(1,835)	(2,309)	(184)
Accounts receivable	34,850	61,899	12,451
Inventories	6,374	12,839	(18,508)
Accrued compensation, warranty and other liabilities	(15,449)	(14,897)	(4,007)
Accounts payable	(3,560)	(21,356)	(33,130)
Deferred profit	26	(4,447)	(5,014)
Other current assets	(16,148)	10,920	(16,202)
Income taxes payable	(2,234)	(24,782)	20,908
Current and long-term operating lease liabilities	(5,903)	(7,454)	(5,258)
Net cash provided by operating activities	2,778	101,470	112,861
Cash flows from investing activities:
Purchases of property, plant and equipment	(10,634)	(16,053)	(14,770)
Net cash received from sale of land, facility and assets	107	216	349
Purchases of short-term investments	(78,573)	(97,290)	(208,856)
Sales and maturities of short-term investments	114,228	152,649	155,406
Settlement of net investment hedge	(3,212)	0	0
Net cash provided by (used in) investing activities	21,916	(30,210)	(67,871)
Cash flows from financing activities:
Repayments of long-term debt	(31,324)	(38,788)	(38,226)
Net issuance (repurchases) of stock, including awards settled in cash	(701)	(5,656)	(1,957)
Payments on current and long-term finance lease liabilities	(24)	(52)	(167)
Acquisition of treasury stock	(26,986)	(23,641)	(50,719)
Net cash provided by (used in) financing activities	(59,035)	(68,137)	(91,069)
Effect of exchange rate changes on cash and cash equivalents	(4,776)	60	(1,781)
Net increase (decrease) in cash and cash equivalents	(39,117)	3,183	(47,860)
Cash and cash equivalents at beginning of year	245,524	242,341	290,201
Cash and cash equivalents at end of year	206,407	245,524	242,341
Supplemental disclosure of cash flow information:
Cash paid for income taxes	24,926	44,276	23,123
Cash paid for interest	803	3,424	3,443
Property, plant and equipment purchases included in accounts payable	454	124	152
Inventory capitalized as capital assets	1,765	1,215	2,529
MCT Worldwide, LLC [Member]
Cash flows from investing activities:
Payment for purchase of MCT, net of cash received	0	(26,331)	0
Equiptest Engineering Pte Ltd. [Member]
Cash flows from investing activities:
Payment for purchase of MCT, net of cash received	$ 0	$ (43,401)	$ 0