Cohu (COHU) 10-Q 7 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 29, 2018	Oct. 23, 2018
Document Information [Line Items]
Entity Registrant Name	COHU INC
Entity Central Index Key	21,535
Trading Symbol	cohu
Current Fiscal Year End Date	--12-29
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding (in shares)		40,700,448
Document Type	10-Q
Document Period End Date	Sep. 29, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 29, 2018		Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 170,695		$ 134,286	[1]
Short-term investments	549		21,329	[1]
Accounts receivable, net	78,575		71,125	[1]
Inventories	63,824		62,085	[1]
Other current assets	8,643		8,613	[1]
Total current assets	322,286		297,438	[1]
Property, plant and equipment, net	32,922		34,172	[1]
Goodwill	64,579		65,613	[1]
Intangible assets, net	13,512		16,748	[1]
Other assets	9,707		6,486	[1]
	443,006		420,457	[1]
Current liabilities:
Short-term borrowings	3,080		3,108	[1]
Current installments of long-term debt	1,021		1,280	[1]
Accounts payable	39,770		37,556	[1]
Accrued compensation and benefits	17,746		20,178	[1]
Accrued warranty	4,357		4,280	[1]
Deferred profit	1,894	[2]	6,608
Income taxes payable	6,072		2,159	[1]
Other accrued liabilities	15,985		10,098	[1]
Total current liabilities	89,925		85,267	[1]
Accrued retirement benefits	18,783		18,544	[1]
Noncurrent deferred gain on sale of facility	9,140		10,233	[1]
Deferred income taxes	3,166		2,921	[1]
Noncurrent income tax liabilities	6,293		6,270	[1]
Long-term debt	3,840		4,575	[1]
Other accrued liabilities	2,852		3,556	[1]
Stockholders' equity:
Preferred stock, $1 par value; 1,000 shares authorized, none issued				[1]
Common stock, $1 par value; 60,000 shares authorized, 28,901 shares issued and outstanding in 2018 and 28,489 shares in 2017	28,901		28,489	[1]
Paid-in capital	130,194		127,663	[1]
Retained earnings	171,110	[2]	150,726	[1]
Accumulated other comprehensive loss	(21,198)		(17,787)
Total stockholders' equity	309,007		289,091	[1]
	$ 443,006		$ 420,457	[1]
[1]	Derived from December 30, 2017 audited financial statements
[2]	Balance sheet line items include the cumulative-effect adjustment recorded on December 31, 2017.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares shares in Thousands	Sep. 29, 2018	Dec. 30, 2017	[1]
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	1,000	1,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	60,000	60,000
Common stock, shares issued (in shares)	28,901	28,489
Common stock, shares outstanding (in shares)	28,901	28,489
[1]	Derived from December 30, 2017 audited financial statements

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Net sales	$ 86,164	$ 93,651	$ 281,131	$ 268,614
Cost and expenses:
Cost of sales	51,786	56,742	165,701	162,319
Research and development	11,088	9,609	33,914	28,851
Selling, general and administrative	16,511	16,882	50,926	47,362
	79,385	83,233	250,541	238,532
Income from operations	6,779	10,418	30,590	30,082
Interest income	326	174	880	417
Income from continuing operations before taxes	7,105	10,592	31,470	30,499
Income tax provision	2,302	1,837	6,897	4,273
Income from continuing operations	4,803	8,755	24,573	26,226
Loss from discontinued operations				(278)
Net income	$ 4,803	$ 8,755	$ 24,573	$ 25,948
Basic:
Income from continuing operations (in dollars per share)	$ 0.17	$ 0.31	$ 0.85	$ 0.95
Loss from discontinued operations (in dollars per share)				(0.01)
Net income (in dollars per share)	0.17	0.31	0.85	0.94
Diluted:
Income from continuing operations (in dollars per share)	0.16	0.30	0.83	0.92
Loss from discontinued operations (in dollars per share)				(0.01)
Net income (in dollars per share)	$ 0.16	$ 0.30	$ 0.83	$ 0.91
Weighted average shares used in computing income (loss) per share:
Basic (in shares)	28,948	28,155	28,814	27,614
Diluted (in shares)	29,770	29,105	29,650	28,640
Cash dividends declared per share (in dollars per share)	$ 0.06	$ 0.06	$ 0.18	$ 0.18

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Net income	$ 4,803	$ 8,755	$ 24,573	$ 25,948
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(475)	2,570	(3,435)	9,975
Adjustments related to postretirement benefits	(24)	12	17	(116)
Change in unrealized gain/loss on investments	9	6	7	7
Other comprehensive income (loss), net of tax	(490)	2,588	(3,411)	9,866
Comprehensive income	$ 4,313	$ 11,343	$ 21,162	$ 35,814

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018		Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 24,573		$ 25,948
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on disposal of microwave communications equipment business			278
Depreciation and amortization	7,276		6,731
Share-based compensation expense	5,497		5,336
Amortization of inventory step-up			1,404
Deferred income taxes	(253)		(932)
Adjustment to contingent consideration liability	657		668
Changes in other accrued liabilities	(409)		427
Changes in other assets	(667)		572
(Gain) loss on disposal of assets	29		(22)
Changes in current assets and liabilities, excluding effects from acquisitions:
Accounts receivable	(8,092)		(9,013)
Inventories	(2,555)		(6,701)
Accounts payable	1,037		(3,620)
Other current assets	328		1,257
Income taxes payable	3,898		1,272
Deferred profit	(3,463)		(299)
Accrued compensation, warranty and other liabilities	1,351		303
Net cash provided by operating activities	29,207		23,609
Cash flows from investing activities, excluding effects from acquisitions:
Sales and maturities of short-term investments	59,480		39,315
Purchases of short-term investments	(38,700)		(23,665)
Cash paid for Kita, net of cash received			(11,716)
Purchases of property, plant and equipment	(2,472)		(4,739)
Cash received from sale of fixed assets	25		109
Net cash provided by (used in) investing activities	18,333		(696)
Cash flows from financing activities:
Issuance (repurchases) of common stock, net	(2,553)		7,149
Cash dividends paid	(5,217)		(4,894)
Payment of contingent consideration for Kita	(823)
Repayments of long-term debt	(975)		(1,280)
Net cash provided by (used in) financing activities	(9,568)		975
Effect of exchange rate changes on cash and cash equivalents	(1,563)		2,051
Net increase in cash and cash equivalents	36,409		25,939
Cash and cash equivalents at beginning of period	134,286	[1]	96,045
Cash and cash equivalents at end of period	170,695		121,984
Supplemental disclosure of cash flow information:
Capitalized debt issuance costs included in current other accrued liabilities	1,522
Cash paid for income taxes	3,549		3,740
Dividends declared but not yet paid	1,734		1,683
Capitalized cloud computing service costs included in accounts payable	1,044
Inventory capitalized as property, plant and equipment	514		113
Property, plant and equipment purchases included in accounts payable	$ 311		$ 594
[1]	Derived from December 30, 2017 audited financial statements

Note 1 - Summary of Significant

Note 1 - Summary of Significant Accounting Policies	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Significant Accounting Policies [Text Block]	1. Summary of Significant Accounting Policies Basis of Presentation Our fiscal years are based on a 52 53 December. December 30, 2017, September 29, 2018, ( third 2018” first nine 2018” September 30, 2017, ( third 2017” first nine 2017” three nine September 29, 2018, 13 39 three nine September 30, 2017, 14 39 Our interim results are not December 30, 2017, 2017 10 Unless otherwise indicated all amounts presented herein pertain only to Cohu, Inc. and exclude the impact of Xcerra Corporation (“Xcerra”) which was acquired on October 1, 2018. 8, 1 10 Concentration of Credit Risk Financial instruments that potentially subject us to significant credit risk consist principally of cash equivalents, short-term investments and trade accounts receivable. We invest in a variety of financial instruments and, by policy, limit the amount of credit exposure with any one Trade accounts receivable are presented net of allowance for doubtful accounts of $ 0.2 September 29, 2018 December 30, 2017. September 29, 2018, may Inventories Inventories are stated at the lower of cost, determined on a first first Inventories by category were as follows ( in thousands September 29, December 30, 2018 2017 Raw materials and purchased parts $ 30,770 $ 27,918 Work in process 24,210 25,130 Finished goods 8,844 9,037 Total inventories $ 63,824 $ 62,085 Property, Plant and Equipment Depreciation and amortization of property, plant and equipment is calculated principally on the straight-line method based on estimated useful lives of thirty forty five fifteen three ten not Property, plant and equipment, at cost, consisted of the following (in thousands) September 29, December 30, 2018 2017 Land and land improvements $ 7,855 $ 8,017 Buildings and building improvements 14,038 13,779 Machinery and equipment 46,894 45,333 68,787 67,129 Less accumulated depreciation and amortization (35,865 ) (32,957 ) Property, plant and equipment, net $ 32,922 $ 34,172 Segment Information We applied the provisions of Accounting Standards Codification (ASC) Topic 280, Segment Reporting 280” 280, 280 one Goodwill, Other Intangible Assets and Long-lived Assets We evaluate goodwill for impairment annually and when an event occurs or circumstances change that indicate that the carrying value may not first second We conduct our annual impairment test as of October 1st no October 1, 2017 may September 29, 2018, not not. may Long-lived assets, other than goodwill, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets might not may not not Foreign Remeasurement and Currency Translation Assets and liabilities of our wholly owned foreign subsidiaries that use the U.S. Dollar as their functional currency are re-measured using exchange rates in effect at the end of the period, except for nonmonetary assets, such as inventories and property, plant and equipment, which are re-measured using historical exchange rates. Revenues and costs are re-measured using average exchange rates for the period, except for costs related to those balance sheet items that are re-measured using historical exchange rates. Gains and losses on foreign currency transactions are recognized as incurred. During the three nine September 29, 2018, $0.2 $1.2 three nine September 30, 2017, $0.2 $2.7 Share-Based Compensation We measure and recognize all share-based compensation under the fair value method. Our estimate of share-based compensation expense requires a number of complex and subjective assumptions including our stock price volatility, employee exercise patterns (expected life of the options) and related tax effects. The assumptions used in calculating the fair value of share-based awards represent our best estimates, but these estimates involve inherent uncertainties and the application of management judgment. Although we believe the assumptions and estimates we have made are reasonable and appropriate, changes in assumptions could materially impact our reported financial results. Reported share-based compensation is classified, in the condensed consolidated interim financial statements, as follows (in thousands) Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Cost of sales $ 125 $ 123 $ 408 $ 327 Research and development 354 278 1,098 856 Selling, general and administrative 1,401 1,459 3,991 4,153 Total share-based compensation 1,880 1,860 5,497 5,336 Income tax benefit (115 ) (107 ) (555 ) (429 ) Total share-based compensation, net $ 1,765 $ 1,753 $ 4,942 $ 4,907 Income (Loss) Per Share Basic income (loss) per common share is computed by dividing net income (loss) by the weighted-average number of common shares outstanding during the reporting period. Diluted income (loss) per share includes the dilutive effect of common shares potentially issuable upon the exercise of stock options, vesting of outstanding restricted stock and performance stock units and issuance of stock under our employee stock purchase plan using the treasury stock method. In loss periods, potentially dilutive securities are excluded from the per share computations due to their anti-dilutive effect. For purposes of computing diluted income (loss) per share, stock options with exercise prices that exceed the average fair market value of our common stock for the period are excluded. For the three September 29, 2018, no nine September 29, 2018, 12,000 three nine September 30, 2017, 5,000 103,000 The following table reconciles the denominators used in computing basic and diluted income (loss) per share ( in thousands) Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Weighted average common shares 28,948 28,155 28,814 27,614 Effect of dilutive securities 822 950 836 1,026 29,770 29,105 29,650 28,640 Cohu has utilized the “control number” concept in the computation of diluted earnings per share to determine whether potential common stock instruments are dilutive. The control number used is income from continuing operations. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share from continuing operations be applied to all other categories of income or loss, regardless of their anti-dilutive effect on such categories Adoption of New Revenue Accounting Standard We adopted ASC Topic 606, Revenue from Contracts with Customers 606” December 31, 2017, first 2018 not December 31, 2017. September 29, 2018 nine September 29, 2018, 606 September 30, 2017 none September 30, 2017, not 606, $1.1 December 31, 2017, 606 Material changes recorded in connection with the cumulative-effect adjustment were as follows ( in thousands Balance at Adjustments Balance at December 30, due to adoption December 31, Financial Statement Line Item 2017 of ASC 606 2017 Deferred profit $ 6,608 $ (1,258 ) $ 5,350 Income taxes payable $ 2,159 $ 201 $ 2,360 Retained earnings $ 150,726 $ 1,057 $ 151,783 The adoption of ASC 606 no three nine September 29, 2018 September 29, 2018 606 (in thousands ): For the Three Months Ended September 29, 2018 Balances without adoption Effect of Condensed Consolidated Statements of Income As Reported of ASC 606 Change Net sales $ 86,164 $ 86,820 $ (656 ) Income tax provision $ 2,302 $ 2,421 $ (119 ) Net income $ 4,803 $ 5,340 $ (537 ) Income per share: Basic: $ 0.17 $ 0.18 $ (0.01 ) Diluted: $ 0.16 $ 0.18 $ (0.02 ) For the Nine Months Ended September 29, 2018 Balances without adoption Effect of Condensed Consolidated Statements of Income As Reported of ASC 606 Change Net sales $ 281,131 $ 279,038 $ 2,093 Income tax provision $ 6,897 $ 6,517 $ 380 Net income $ 24,573 $ 22,860 $ 1,713 Income per share: Basic: $ 0.85 $ 0.79 $ 0.06 Diluted: $ 0.83 $ 0.77 $ 0.06 Balances without adoption Effect of Condensed Consolidated Balance Sheets* As Reported of ASC 606 Change Deferred profit $ 1,894 $ 5,396 $ (3,502 ) Retained earnings $ 171,110 $ 168,339 $ 2,771 * Balance sheet line items include the cumulative-effect adjustment recorded on December 31, 2017. Under ASC 606 may 606. Revenue Recognition Our net sales are derived from the sale of products and services and are adjusted for estimated returns and allowances, which historically have been insignificant. We recognize revenue when the obligations under the terms of a contract with our customers are satisfied; generally, this occurs with the transfer of control of our systems, non-system products or services. In circumstances where control is not Revenue for established products that have previously satisfied a customer’s acceptance requirements is generally recognized upon shipment. In cases where a prior history of customer acceptance cannot be demonstrated or from sales where customer payment dates are not Certain of our equipment sales have multiple performance obligations. These arrangements involve the delivery or performance of multiple performance obligations, and transfer of control of performance obligations may Unsatisfied performance obligations primarily represent contracts for products with future delivery dates and with an original expected duration of one 606, not one We generally sell our equipment with a product warranty. The product warranty provides assurance to customers that delivered products are as specified in the contract (an “assurance-type warranty”). Therefore, we account for such product warranties under ASC 460, Guarantees 460 not The transaction price reflects our expectations about the consideration we will be entitled to receive from the customer and may not not Our contracts are typically less than one 606 one Accounts receivable represents our unconditional right to receive consideration from our customer. Payments terms do not one not no no On shipments where sales are not September 29, 2018, $3.6 $1.9 one $1.1 December 30, 2017, $10.4 $6.6 one $0.8 September 29, 2018, $1.1 606 first 2018. Net sales by type are as follows (in thousands): Three Months Ended Nine Months Ended September 29, 2018 September 29, 2018 Systems $ 42,278 $ 152,846 Non-systems 43,886 128,285 Net sales $ 86,164 $ 281,131 Revenue by geographic area based upon product shipment destination ( in thousands Three Months Ended Nine Months Ended September 29, 2018 September 29, 2018 China $ 23,628 $ 63,011 United States 11,585 41,725 Malaysia 13,682 38,539 Philippines 11,158 31,620 Rest of the World 26,111 106,236 Net sales $ 86,164 $ 281,131 A small number of customers historically have been responsible for a significant portion of our net sales. Significant customer concentration information is as follows: Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Customers individually accounting for more than 10% of net sales one two one two Percentage of net sales 11.2 % 26.5 % 10.8 % 28.5 % Accumulated Other Comprehensive Loss Our accumulated other comprehensive loss balance totaled approximately $21.2 $17.8 September 29, 2018 December 30, 2017, not first nine 2018 2017 not Retiree Medical Benefits We provide post-retirement health benefits to certain executives, directors and their eligible dependents under a noncontributory plan. The net periodic benefit cost incurred during the first nine 2018 2017 not Discontinued Operations In 2015, $4.9 $2.5 no As part of the divestiture of BMS we recorded a contingent consideration receivable that was classified as Level 3 3, three 2016 2017 2017, Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In August 2018, 2018 15, Intangibles – Goodwill and Other – Internal-Use Software 350 40 No. 2015 05, Customers Accounting for Fees in a Cloud Computing Agreement, 2018 15 350 40 2018 15 December 15, 2019, 2018 15 third 2018 $1.5 September 29, 2018. $0.3 $1.2 In March 2017, No. 2017 07 , Compensation – Retirement Benefits (Topic 715 December 15, 2017, 2017 07 not In January 2017, No. 2017 01, Clarifying the Definition of a Business December 15, 2017. 2017 01 not In November 2016, No. 2016 18, Restricted Cash December 15, 2017. 2016 18 not In October 2016, 2016 16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory. 2016 16 2016 16 third 2016 16 December 15, 2017 2016 16 not In August 2016, No. 2016 15 , Classification of Certain Cash Receipts and Cash Payments. eight December 15, 2017. 2016 15 not Recently Issued Accounting Pronouncements In August 2018, 2018 14, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans, not December 15, 2020 not 2018 14 In August 2018, 2018 13 , Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement not December 15, 2019. 3 not 2018 13 In February 2018, 2018 02, Income Statement-Reporting Comprehensive Income 2018 02 December 15, 2018, not 2018 02 may In January 2017, No. 2017 04, Simplifying the Test for Goodwill Impairment 2 not December 15, 2019. not In February 2016, 2016 02 Leases (Topic 842 December 15, 2018. 2016 02 During the second 2018, one four first nine 2018, July 2018, 2018 10, Codification Improvements to Topic 842, 2018 10 2016 02. July 2018, 2018 11, Targeted Improvements to Topic 842, 2018 11 2016 02 840, Leases not 2016 02.

Note 2 - Business Acquisitions,

Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Business Combination Disclosure [Text Block]	2. Business Acquisitions, Goodwill and Purchased Intangible Assets Kita On January 4, 2017, $1.0 nine September 30, 2017. No nine September 29, 2018. The Acquisition has been accounted for in conformity with FASB Accounting Standards Codification 805, Business Combinations in thousands Cash paid to Kita shareholders $ 15,000 Fair value of contingent consideration 823 Total purchase price $ 15,823 The contingent consideration represents the estimated fair value of future payments totaling up to $ 3.0 2017 2018 September 29, 2018 3 3 three The following table presents the changes in fair value of contingent consideration during the year ended December 30, 2017, nine September 29, 2018 ( in thousands Fair Value of Contingent Consideration Balance, December 31, 2016 $ - Fair value of consideration at acquisition date 823 Mark-to-market adjustments charged to expense 1,423 Impact of currency exchange 7 Balance, December 30, 2017 2,253 Mark-to-market adjustments charged to expense 657 Settlement of contingent consideration (1,500 ) Impact of currency exchange 60 Balance, September 29, 2018 $ 1,470 The Acquisition was nontaxable to Cohu and certain of the assets acquired, including goodwill and intangibles, will not Goodwill and Intangible Assets Changes in the carrying value of goodwill during the year ended December 30, 2017, nine September 29, 2018 in thousands Goodwill Balance, December 31, 2016 $ 58,849 Additions, net 2,654 Impact of currency exchange 4,110 Balance, December 30, 2017 65,613 Impact of currency exchange (1,034 ) Balance, September 29, 2018 $ 64,579 Purchased intangible assets, subject to amortization are as follows ( in thousands September 29, 2018 December 30, 2017 Remaining Weighted Average Gross Amort Gross Carrying Accum. Period Carrying Accum. Amount Amort. (in years) Amount Amort. Developed technology $ 20,632 $ 14,468 2.7 $ 20,780 $ 12,623 Customer relationships 7,877 5,572 2.3 7,934 4,838 Trade names 6,088 1,301 11.5 6,185 972 Covenant not-to-compete 310 54 8.3 313 31 Total intangible assets $ 34,907 $ 21,395 $ 35,212 $ 18,464 Amortization expense related to intangible assets was approximately $1.0 third 2018 $3.1 first nine 2018. $1.1 third 2017 $3.2 first nine 2017.

Note 3 - Financial Instruments

Note 3 - Financial Instruments Measured at Fair Value	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]	3. Financial Instruments Measured at Fair Value Our cash, cash equivalents, and short-term investments consisted primarily of cash and other investment grade securities. We do not Gains and losses on investments are calculated using the specific-identification method and are recognized during the period in which the investment is sold or when an investment experiences an other-than-temporary decline in value. Factors that could indicate an impairment exists include, but are not not Investments that we have classified as short-term, by security type, are as follows ( in thousands ) September 29, 2018 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses (1) Value Foreign government security $ 549 $ - $ - $ 549 December 30, 2017 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses (1) Value Corporate debt securities (2) $ 12,784 $ 1 $ 6 $ 12,779 U.S. treasury securities 7,935 - 4 7,931 Foreign government security 619 - - 619 $ 21,338 $ 1 $ 10 $ 21,329 ( 1 As of September 29, 2018, no December 30, 2017, $13.2 ( 2 Corporate debt securities include investments in financial and other corporate institutions. No Effective maturities of short-term investments are as follows (in thousands) September 29, 2018 December 30, 2017 Amortized Estimated Amortized Estimated Cost Fair Value Cost Fair Value Due in one year or less $ - $ - $ 21,338 $ 21,329 Due after one year through three years 549 549 - - $ 549 $ 549 $ 21,338 $ 21,329 Accounting standards pertaining to fair value measurements establish a three 1, 2, 3, no 1. 2. The following table summarizes, by major security type, our financial instruments that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands) Fair value measurements at September 29, 2018 using: Total estimated Level 1 Level 2 Level 3 fair value Cash $ 141,075 $ - $ - $ 141,075 Money market funds - 29,620 - 29,620 Foreign government security - 549 - 549 $ 141,075 $ 30,169 $ - $ 171,244 Fair value measurements at December 30, 2017 using: Total estimated Level 1 Level 2 Level 3 fair value Cash $ 100,850 $ - $ - $ 100,850 Corporate debt securities - 22,014 - 22,014 U.S. treasury securities - 8,431 - 8,431 Government-sponsored enterprise securities - 1,496 - 1,496 Money market funds - 22,205 - 22,205 Foreign government security - 619 - 619 $ 100,850 $ 54,765 $ - $ 155,615

Note 4 - Employee Stock Benefit

Note 4 - Employee Stock Benefit Plans	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	4. Employee Stock Benefit Plans Our 2005 “2005 may not September 29, 2018, 1,204,761 2005 Stock Options Stock options may one four 2015 ten first nine 2018 not 64,300 At September 29, 2018, 407,926 $10.24 $6.1 3.9 Restricted Stock Units We grant restricted stock units (“RSUs”) to certain employees, consultants and directors. RSUs vest in annual increments that range from one four not not not September 29, 2018. In the first nine 2018 286,709 432,031 September 29, 2018, 800,865 $20.1 1.3 Performance Stock Units We also grant performance stock units (“PSUs”) to senior executives as a part of our long-term equity compensation program. The number of shares of common stock that will ultimately be issued to settle PSUs granted in 2018, 2017 2016 25% 200% three 2015, two 2018, 2017 2016 100% third 2015 50% second third We estimated the fair value of the PSUs using a Monte Carlo simulation model on the date of grant. Compensation expense is recognized ratably over the derived service period. New shares of our common stock will be issued on the date the PSUs vest net of the minimum statutory tax withholding requirements to be paid by us on behalf of our employees. As a result, the actual number of shares issued will be fewer than the actual number outstanding at September 29, 2018. In the first nine 2018, 88,418 40,640 September 29, 2018, 339,771 $8.5 1.3 Employee Stock Purchase Plan The Cohu, Inc. 1997 may 85 6 first nine 2018, 41,694 559,646

Note 5 - Income Taxes

Note 5 - Income Taxes	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	5. Income Taxes For the three nine September 29, 2018, three September 29, 2018 September 30, 2017, 32.4% 17.3%, 21.9% 14.0% nine September 29, 2018 September 30, 2017, three nine September 29, 2018 $ 0.6 2018 2017 We have not fourth 2017. September 29, 2018 2018 No. 118 118” Due to the complexity of the Tax Act’s global intangible low-taxed income (“GILTI”) tax rules, we are continuing to evaluate this provision and the application of ASC Topic 740, 740” not nine September 29, 2018 not Our German subsidiaries income tax returns for 2012 2016 Other than for foreign currency exchange rate changes and the Kita acquisition, there was no three nine September 29, 2018 September 30, 2017.

Note 6 - Contingencies

Note 6 - Contingencies	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Contingencies Disclosure [Text Block]	6. Contingencies From time-to-time we are involved in various legal proceedings, examinations by various tax authorities and claims that have arisen in the ordinary course of our business. The outcome of any litigation is inherently uncertain. While there can be no not

Note 7 - Guarantees and Other O

Note 7 - Guarantees and Other Obligations	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Commitments Contingencies and Guarantees [Text Block]	7. Guarantees and Other Obligations Product Warranty Our products are generally sold with warranty periods that range from 12 36 460, not Changes in accrued warranty were as follows ( in thousands Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Balance at beginning of period $ 4,948 $ 5,070 $ 4,848 $ 4,350 Warranty expense accruals 1,600 1,720 4,988 5,446 Warranty payments (1,946 ) (1,773 ) (5,234 ) (4,829 ) Warranty liability assumed - - - 50 Balance at end of period $ 4,602 $ 5,017 $ 4,602 $ 5,017 Accrued warranty amounts expected to be incurred after one $0.2 September 29, 2018, $0.6 December 30, 2017. Borrowings Revolving Lines of Credit We have credit agreements with multiple financial institutions in Japan under which they administer lines of credit on behalf of our wholly owned Kita subsidiary. The credit facilities renew monthly and provide Kita with access to working capital totaling up to $6.2 September 29, 2018, $3.1 Term Loans We have long-term term loans from a series of Japanese financial institutions related to the expansion of Kita’s facility in Osaka, Japan. The loans are collateralized by the facility and land, carry interest rates ranging from 0.05% 0.45%, 2034. September 29, 2018 $4.8 $1.0 September 29, 2018. Lines of Credit We have one one 2.0 September 29, 2018 December 30, 2017, no

Note 8 - Acquisition of Xcerra

Note 8 - Acquisition of Xcerra	9 Months Ended
	Sep. 29, 2018
Notes to Financial Statements
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	8. Acquisition of Xcerra Completion of the Acquisition of Xcerra Pursuant to an Agreement and Plan of Merger (the “Merger Agreement”) dated as of May 7, 2018 October 1, 2018 ( $5.2 first nine 2018. At the Effective Time, each share of Xcerra’s common stock, par value $0.05 $9.00 0.2109 $1.00 No 2.11 On October 1, 2018, $70.5 Consideration Transferred On October 1, 2018, 11,776,315 $502.5 530,000 October 1, 2018. Secured Term Loan Facility To provide the majority of the Cash Consideration for the Merger, on October 1, 2018, $350.0 On October 1, 2018, Loans under the Credit Facility amortize in equal quarterly installments equal to 0.25% 1.00% sixth may not October 1, 2025. Loans under the Credit Facility bear interest at a floating annual rate equal to the LIBOR plus a margin of 3.00%. 2.00% The Credit Agreement has incremental facility capacity in an aggregate amount of the greater of $145 100% $35 first may The Credit Agreement contains certain customary affirmative and negative covenants, including covenants that limit the ability of Cohu and its subsidiaries to, among other things, grant liens, incur debt, dispose of assets, make loans and investments, make acquisitions, make certain restricted payments, merge or consolidate or change their business, in each case subject to customary exceptions for a credit facility of this size and type. The Credit Agreement includes customary events of default that include, among other things, non-payment of principal, interest or fees, inaccuracy of representations and warranties, breach of covenants, cross-default to certain material indebtedness, bankruptcy and insolvency and change of control. Upon the occurrence and during the continuance of an event of default, the lenders may may

Significant Accounting Policies

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 29, 2018
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation Our fiscal years are based on a 52 53 December. December 30, 2017, September 29, 2018, ( third 2018” first nine 2018” September 30, 2017, ( third 2017” first nine 2017” three nine September 29, 2018, 13 39 three nine September 30, 2017, 14 39 Our interim results are not December 30, 2017, 2017 10 Unless otherwise indicated all amounts presented herein pertain only to Cohu, Inc. and exclude the impact of Xcerra Corporation (“Xcerra”) which was acquired on October 1, 2018. 8, 1 10
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentration of Credit Risk Financial instruments that potentially subject us to significant credit risk consist principally of cash equivalents, short-term investments and trade accounts receivable. We invest in a variety of financial instruments and, by policy, limit the amount of credit exposure with any one Trade accounts receivable are presented net of allowance for doubtful accounts of $0.2 September 29, 2018 December 30, 2017. September 29, 2018, may
Inventory, Policy [Policy Text Block]	Inventories Inventories are stated at the lower of cost, determined on a first first Inventories by category were as follows ( in thousands September 29, December 30, 2018 2017 Raw materials and purchased parts $ 30,770 $ 27,918 Work in process 24,210 25,130 Finished goods 8,844 9,037 Total inventories $ 63,824 $ 62,085
Property, Plant and Equipment, Policy [Policy Text Block]	Property, Plant and Equipment Depreciation and amortization of property, plant and equipment is calculated principally on the straight-line method based on estimated useful lives of thirty forty five fifteen three ten not Property, plant and equipment, at cost, consisted of the following (in thousands) September 29, December 30, 2018 2017 Land and land improvements $ 7,855 $ 8,017 Buildings and building improvements 14,038 13,779 Machinery and equipment 46,894 45,333 68,787 67,129 Less accumulated depreciation and amortization (35,865 ) (32,957 ) Property, plant and equipment, net $ 32,922 $ 34,172
Segment Reporting, Policy [Policy Text Block]	Segment Information We applied the provisions of Accounting Standards Codification (ASC) Topic 280, Segment Reporting 280” 280, 280 one
Goodwill and Intangible Assets, Policy [Policy Text Block]	Goodwill, Other Intangible Assets and Long-lived Assets We evaluate goodwill for impairment annually and when an event occurs or circumstances change that indicate that the carrying value may not first second We conduct our annual impairment test as of October 1st no October 1, 2017 may September 29, 2018, not not. may Long-lived assets, other than goodwill, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets might not may not not
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Remeasurement and Currency Translation Assets and liabilities of our wholly owned foreign subsidiaries that use the U.S. Dollar as their functional currency are re-measured using exchange rates in effect at the end of the period, except for nonmonetary assets, such as inventories and property, plant and equipment, which are re-measured using historical exchange rates. Revenues and costs are re-measured using average exchange rates for the period, except for costs related to those balance sheet items that are re-measured using historical exchange rates. Gains and losses on foreign currency transactions are recognized as incurred. During the three nine September 29, 2018, $0.2 $1.2 three nine September 30, 2017, $0.2 $2.7
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Share-Based Compensation We measure and recognize all share-based compensation under the fair value method. Our estimate of share-based compensation expense requires a number of complex and subjective assumptions including our stock price volatility, employee exercise patterns (expected life of the options) and related tax effects. The assumptions used in calculating the fair value of share-based awards represent our best estimates, but these estimates involve inherent uncertainties and the application of management judgment. Although we believe the assumptions and estimates we have made are reasonable and appropriate, changes in assumptions could materially impact our reported financial results. Reported share-based compensation is classified, in the condensed consolidated interim financial statements, as follows (in thousands) Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Cost of sales $ 125 $ 123 $ 408 $ 327 Research and development 354 278 1,098 856 Selling, general and administrative 1,401 1,459 3,991 4,153 Total share-based compensation 1,880 1,860 5,497 5,336 Income tax benefit (115 ) (107 ) (555 ) (429 ) Total share-based compensation, net $ 1,765 $ 1,753 $ 4,942 $ 4,907
Income Tax, Policy [Policy Text Block]	Income (Loss) Per Share Basic income (loss) per common share is computed by dividing net income (loss) by the weighted-average number of common shares outstanding during the reporting period. Diluted income (loss) per share includes the dilutive effect of common shares potentially issuable upon the exercise of stock options, vesting of outstanding restricted stock and performance stock units and issuance of stock under our employee stock purchase plan using the treasury stock method. In loss periods, potentially dilutive securities are excluded from the per share computations due to their anti-dilutive effect. For purposes of computing diluted income (loss) per share, stock options with exercise prices that exceed the average fair market value of our common stock for the period are excluded. For the three September 29, 2018, no nine September 29, 2018, 12,000 three nine September 30, 2017, 5,000 103,000 The following table reconciles the denominators used in computing basic and diluted income (loss) per share ( in thousands) Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Weighted average common shares 28,948 28,155 28,814 27,614 Effect of dilutive securities 822 950 836 1,026 29,770 29,105 29,650 28,640 Cohu has utilized the “control number” concept in the computation of diluted earnings per share to determine whether potential common stock instruments are dilutive. The control number used is income from continuing operations. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share from continuing operations be applied to all other categories of income or loss, regardless of their anti-dilutive effect on such categories
Adoption of New Accounting Standard [Policy Text Block]	Adoption of New Revenue Accounting Standard We adopted ASC Topic 606, Revenue from Contracts with Customers 606” December 31, 2017, first 2018 not December 31, 2017. September 29, 2018 nine September 29, 2018, 606 September 30, 2017 none September 30, 2017, not 606, $1.1 December 31, 2017, 606 Material changes recorded in connection with the cumulative-effect adjustment were as follows ( in thousands Balance at Adjustments Balance at December 30, due to adoption December 31, Financial Statement Line Item 2017 of ASC 606 2017 Deferred profit $ 6,608 $ (1,258 ) $ 5,350 Income taxes payable $ 2,159 $ 201 $ 2,360 Retained earnings $ 150,726 $ 1,057 $ 151,783 The adoption of ASC 606 no three nine September 29, 2018 September 29, 2018 606 (in thousands ): For the Three Months Ended September 29, 2018 Balances without adoption Effect of Condensed Consolidated Statements of Income As Reported of ASC 606 Change Net sales $ 86,164 $ 86,820 $ (656 ) Income tax provision $ 2,302 $ 2,421 $ (119 ) Net income $ 4,803 $ 5,340 $ (537 ) Income per share: Basic: $ 0.17 $ 0.18 $ (0.01 ) Diluted: $ 0.16 $ 0.18 $ (0.02 ) For the Nine Months Ended September 29, 2018 Balances without adoption Effect of Condensed Consolidated Statements of Income As Reported of ASC 606 Change Net sales $ 281,131 $ 279,038 $ 2,093 Income tax provision $ 6,897 $ 6,517 $ 380 Net income $ 24,573 $ 22,860 $ 1,713 Income per share: Basic: $ 0.85 $ 0.79 $ 0.06 Diluted: $ 0.83 $ 0.77 $ 0.06 Balances without adoption Effect of Condensed Consolidated Balance Sheets* As Reported of ASC 606 Change Deferred profit $ 1,894 $ 5,396 $ (3,502 ) Retained earnings $ 171,110 $ 168,339 $ 2,771 * Balance sheet line items include the cumulative-effect adjustment recorded on December 31, 2017. Under ASC 606 may 606.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition Our net sales are derived from the sale of products and services and are adjusted for estimated returns and allowances, which historically have been insignificant. We recognize revenue when the obligations under the terms of a contract with our customers are satisfied; generally, this occurs with the transfer of control of our systems, non-system products or services. In circumstances where control is not Revenue for established products that have previously satisfied a customer’s acceptance requirements is generally recognized upon shipment. In cases where a prior history of customer acceptance cannot be demonstrated or from sales where customer payment dates are not Certain of our equipment sales have multiple performance obligations. These arrangements involve the delivery or performance of multiple performance obligations, and transfer of control of performance obligations may Unsatisfied performance obligations primarily represent contracts for products with future delivery dates and with an original expected duration of one 606, not one We generally sell our equipment with a product warranty. The product warranty provides assurance to customers that delivered products are as specified in the contract (an “assurance-type warranty”). Therefore, we account for such product warranties under ASC 460, Guarantees 460 not The transaction price reflects our expectations about the consideration we will be entitled to receive from the customer and may not not Our contracts are typically less than one 606 one Accounts receivable represents our unconditional right to receive consideration from our customer. Payments terms do not one not no no On shipments where sales are not September 29, 2018, $3.6 $1.9 one $1.1 December 30, 2017, $10.4 $6.6 one $0.8 September 29, 2018, $1.1 606 first 2018. Net sales by type are as follows (in thousands): Three Months Ended Nine Months Ended September 29, 2018 September 29, 2018 Systems $ 42,278 $ 152,846 Non-systems 43,886 128,285 Net sales $ 86,164 $ 281,131 Revenue by geographic area based upon product shipment destination ( in thousands Three Months Ended Nine Months Ended September 29, 2018 September 29, 2018 China $ 23,628 $ 63,011 United States 11,585 41,725 Malaysia 13,682 38,539 Philippines 11,158 31,620 Rest of the World 26,111 106,236 Net sales $ 86,164 $ 281,131 A small number of customers historically have been responsible for a significant portion of our net sales. Significant customer concentration information is as follows: Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Customers individually accounting for more than 10% of net sales one two one two Percentage of net sales 11.2 % 26.5 % 10.8 % 28.5 %
Comprehensive Income, Policy [Policy Text Block]	Accumulated Other Comprehensive Loss Our accumulated other comprehensive loss balance totaled approximately $21.2 $17.8 September 29, 2018 December 30, 2017, not first nine 2018 2017 not
Pension and Other Postretirement Plans, Policy [Policy Text Block]	Retiree Medical Benefits We provide post-retirement health benefits to certain executives, directors and their eligible dependents under a noncontributory plan. The net periodic benefit cost incurred during the first nine 2018 2017 not
Discontinued Operations, Policy [Policy Text Block]	Discontinued Operations In 2015, $4.9 $2.5 no As part of the divestiture of BMS we recorded a contingent consideration receivable that was classified as Level 3 3, three 2016 2017 2017,
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In August 2018, 2018 15, Intangibles – Goodwill and Other – Internal-Use Software 350 40 No. 2015 05, Customers Accounting for Fees in a Cloud Computing Agreement, 2018 15 350 40 2018 15 December 15, 2019, 2018 15 third 2018 $1.5 September 29, 2018. $0.3 $1.2 In March 2017, No. 2017 07 , Compensation – Retirement Benefits (Topic 715 December 15, 2017, 2017 07 not In January 2017, No. 2017 01, Clarifying the Definition of a Business December 15, 2017. 2017 01 not In November 2016, No. 2016 18, Restricted Cash December 15, 2017. 2016 18 not In October 2016, 2016 16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory. 2016 16 2016 16 third 2016 16 December 15, 2017 2016 16 not In August 2016, No. 2016 15 , Classification of Certain Cash Receipts and Cash Payments. eight December 15, 2017. 2016 15 not Recently Issued Accounting Pronouncements In August 2018, 2018 14, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans, not December 15, 2020 not 2018 14 In August 2018, 2018 13 , Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement not December 15, 2019. 3 not 2018 13 In February 2018, 2018 02, Income Statement-Reporting Comprehensive Income 2018 02 December 15, 2018, not 2018 02 may In January 2017, No. 2017 04, Simplifying the Test for Goodwill Impairment 2 not December 15, 2019. not In February 2016, 2016 02 Leases (Topic 842 December 15, 2018. 2016 02 During the second 2018, one four first nine 2018, July 2018, 2018 10, Codification Improvements to Topic 842, 2018 10 2016 02. July 2018, 2018 11, Targeted Improvements to Topic 842, 2018 11 2016 02 840, Leases not 2016 02.

Note 1 - Summary of Significa_2

Note 1 - Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 29, 2018
Notes Tables
Schedule of Inventory, Current [Table Text Block]	September 29, December 30, 2018 2017 Raw materials and purchased parts $ 30,770 $ 27,918 Work in process 24,210 25,130 Finished goods 8,844 9,037 Total inventories $ 63,824 $ 62,085
Property, Plant and Equipment [Table Text Block]	September 29, December 30, 2018 2017 Land and land improvements $ 7,855 $ 8,017 Buildings and building improvements 14,038 13,779 Machinery and equipment 46,894 45,333 68,787 67,129 Less accumulated depreciation and amortization (35,865 ) (32,957 ) Property, plant and equipment, net $ 32,922 $ 34,172
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Cost of sales $ 125 $ 123 $ 408 $ 327 Research and development 354 278 1,098 856 Selling, general and administrative 1,401 1,459 3,991 4,153 Total share-based compensation 1,880 1,860 5,497 5,336 Income tax benefit (115 ) (107 ) (555 ) (429 ) Total share-based compensation, net $ 1,765 $ 1,753 $ 4,942 $ 4,907
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Weighted average common shares 28,948 28,155 28,814 27,614 Effect of dilutive securities 822 950 836 1,026 29,770 29,105 29,650 28,640
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	Balance at Adjustments Balance at December 30, due to adoption December 31, Financial Statement Line Item 2017 of ASC 606 2017 Deferred profit $ 6,608 $ (1,258 ) $ 5,350 Income taxes payable $ 2,159 $ 201 $ 2,360 Retained earnings $ 150,726 $ 1,057 $ 151,783 For the Three Months Ended September 29, 2018 Balances without adoption Effect of Condensed Consolidated Statements of Income As Reported of ASC 606 Change Net sales $ 86,164 $ 86,820 $ (656 ) Income tax provision $ 2,302 $ 2,421 $ (119 ) Net income $ 4,803 $ 5,340 $ (537 ) Income per share: Basic: $ 0.17 $ 0.18 $ (0.01 ) Diluted: $ 0.16 $ 0.18 $ (0.02 ) For the Nine Months Ended September 29, 2018 Balances without adoption Effect of Condensed Consolidated Statements of Income As Reported of ASC 606 Change Net sales $ 281,131 $ 279,038 $ 2,093 Income tax provision $ 6,897 $ 6,517 $ 380 Net income $ 24,573 $ 22,860 $ 1,713 Income per share: Basic: $ 0.85 $ 0.79 $ 0.06 Diluted: $ 0.83 $ 0.77 $ 0.06 Balances without adoption Effect of Condensed Consolidated Balance Sheets* As Reported of ASC 606 Change Deferred profit $ 1,894 $ 5,396 $ (3,502 ) Retained earnings $ 171,110 $ 168,339 $ 2,771
Disaggregation of Revenue [Table Text Block]	Three Months Ended Nine Months Ended September 29, 2018 September 29, 2018 Systems $ 42,278 $ 152,846 Non-systems 43,886 128,285 Net sales $ 86,164 $ 281,131 Three Months Ended Nine Months Ended September 29, 2018 September 29, 2018 China $ 23,628 $ 63,011 United States 11,585 41,725 Malaysia 13,682 38,539 Philippines 11,158 31,620 Rest of the World 26,111 106,236 Net sales $ 86,164 $ 281,131
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Customers individually accounting for more than 10% of net sales one two one two Percentage of net sales 11.2 % 26.5 % 10.8 % 28.5 %

Note 2 - Business Acquisition_2

Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets (Tables)	9 Months Ended
	Sep. 29, 2018
Notes Tables
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	Cash paid to Kita shareholders $ 15,000 Fair value of contingent consideration 823 Total purchase price $ 15,823
Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table Text Block]	Fair Value of Contingent Consideration Balance, December 31, 2016 $ - Fair value of consideration at acquisition date 823 Mark-to-market adjustments charged to expense 1,423 Impact of currency exchange 7 Balance, December 30, 2017 2,253 Mark-to-market adjustments charged to expense 657 Settlement of contingent consideration (1,500 ) Impact of currency exchange 60 Balance, September 29, 2018 $ 1,470
Schedule of Goodwill [Table Text Block]	Goodwill Balance, December 31, 2016 $ 58,849 Additions, net 2,654 Impact of currency exchange 4,110 Balance, December 30, 2017 65,613 Impact of currency exchange (1,034 ) Balance, September 29, 2018 $ 64,579
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	September 29, 2018 December 30, 2017 Remaining Weighted Average Gross Amort Gross Carrying Accum. Period Carrying Accum. Amount Amort. (in years) Amount Amort. Developed technology $ 20,632 $ 14,468 2.7 $ 20,780 $ 12,623 Customer relationships 7,877 5,572 2.3 7,934 4,838 Trade names 6,088 1,301 11.5 6,185 972 Covenant not-to-compete 310 54 8.3 313 31 Total intangible assets $ 34,907 $ 21,395 $ 35,212 $ 18,464

Note 3 - Financial Instrument_2

Note 3 - Financial Instruments Measured at Fair Value (Tables)	9 Months Ended
	Sep. 29, 2018
Notes Tables
Available-for-sale Securities [Table Text Block]	September 29, 2018 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses (1) Value Foreign government security $ 549 $ - $ - $ 549 December 30, 2017 Gross Gross Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses (1) Value Corporate debt securities (2) $ 12,784 $ 1 $ 6 $ 12,779 U.S. treasury securities 7,935 - 4 7,931 Foreign government security 619 - - 619 $ 21,338 $ 1 $ 10 $ 21,329
Investments Classified by Contractual Maturity Date [Table Text Block]	September 29, 2018 December 30, 2017 Amortized Estimated Amortized Estimated Cost Fair Value Cost Fair Value Due in one year or less $ - $ - $ 21,338 $ 21,329 Due after one year through three years 549 549 - - $ 549 $ 549 $ 21,338 $ 21,329
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	Fair value measurements at September 29, 2018 using: Total estimated Level 1 Level 2 Level 3 fair value Cash $ 141,075 $ - $ - $ 141,075 Money market funds - 29,620 - 29,620 Foreign government security - 549 - 549 $ 141,075 $ 30,169 $ - $ 171,244 Fair value measurements at December 30, 2017 using: Total estimated Level 1 Level 2 Level 3 fair value Cash $ 100,850 $ - $ - $ 100,850 Corporate debt securities - 22,014 - 22,014 U.S. treasury securities - 8,431 - 8,431 Government-sponsored enterprise securities - 1,496 - 1,496 Money market funds - 22,205 - 22,205 Foreign government security - 619 - 619 $ 100,850 $ 54,765 $ - $ 155,615

Note 7 - Guarantees and Other_2

Note 7 - Guarantees and Other Obligations (Tables)	9 Months Ended
	Sep. 29, 2018
Notes Tables
Schedule of Product Warranty Liability [Table Text Block]	Three Months Ended Nine Months Ended September 29, September 30, September 29, September 30, 2018 2017 2018 2017 Balance at beginning of period $ 4,948 $ 5,070 $ 4,848 $ 4,350 Warranty expense accruals 1,600 1,720 4,988 5,446 Warranty payments (1,946 ) (1,773 ) (5,234 ) (4,829 ) Warranty liability assumed - - - 50 Balance at end of period $ 4,602 $ 5,017 $ 4,602 $ 5,017

Note 1 - Summary of Significa_3

Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	Oct. 01, 2017USD ($)	Sep. 29, 2018USD ($)shares		Sep. 30, 2017USD ($)shares	Sep. 29, 2018USD ($)shares		Sep. 30, 2017USD ($)shares	Dec. 26, 2015USD ($)	Dec. 31, 2017USD ($)	Dec. 30, 2017USD ($)
Allowance for Doubtful Accounts Receivable, Current, Ending Balance		$ 200			$ 200					$ 200
Number of Operating Segments					1
Goodwill and Intangible Asset Impairment, Total	$ 0
Foreign Currency Transaction Gain (Loss), Realized		$ (200)		$ (200)	$ 1,200		$ (2,700)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares		0		5,000	12,000		103,000
Contract with Customer, Liability, Total		$ 0		$ 0	$ 0		$ 0			0
Deferred Revenue		3,600			3,600					10,400
Deferred Profit		1,894	[1]		1,894	[1]			$ 5,350	6,608
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total		(21,198)			(21,198)					(17,787)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax					0		0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total					0		0
Capitalized Computer Software, Net, Ending Balance		1,500			1,500
Contract with Customer, Asset, Net, Total		0		$ 0	0		$ 0			0
Broadcast Microwave Services, Inc. (“BMS”) [Member]
Proceeds from Divestiture of Businesses								$ 4,900
Disposal Group, Including Discontinued Operation, Contingent Consideration								$ 2,500
Non-current Other Accrued Liabilities [Member]
Deferred Profit Recognized After Year One		1,100			1,100					$ 800
Other Current Assets [Member]
Capitalized Computer Software, Net, Ending Balance		300			300
Other Noncurrent Assets [Member]
Capitalized Computer Software, Net, Ending Balance		$ 1,200			$ 1,200
Accounting Standards Update 2014-09 [Member]
Deferred Profit									(1,258)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption									$ 1,100
Building [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life					30 years
Building [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life					40 years
Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life					5 years
Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life					15 years
Machinery, Equipment and Software [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life					3 years
Machinery, Equipment and Software [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life					10 years
[1]	Balance sheet line items include the cumulative-effect adjustment recorded on December 31, 2017.

Note 1 - Summary of Significa_4

Note 1 - Summary of Significant Accounting Policies - Inventories (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Raw materials and purchased parts	$ 30,770	$ 27,918
Work in process	24,210	25,130
Finished goods	8,844	9,037
Total inventories	$ 63,824	$ 62,085	[1]
[1]	Derived from December 30, 2017 audited financial statements

Note 1 - Summary of Significa_5

Note 1 - Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Property, plant and equipment	$ 68,787	$ 67,129
Less accumulated depreciation and amortization	(35,865)	(32,957)
Property, plant and equipment, net	32,922	34,172	[1]
Land and Land Improvements [Member]
Property, plant and equipment	7,855	8,017
Building and Building Improvements [Member]
Property, plant and equipment	14,038	13,779
Machinery and Equipment [Member]
Property, plant and equipment	$ 46,894	$ 45,333
[1]	Derived from December 30, 2017 audited financial statements

Note 1 - Summary of Significa_6

Note 1 - Summary of Significant Accounting Policies - Reported Share-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Allocated share-based compensation	$ 1,880	$ 1,860	$ 5,497	$ 5,336
Income tax benefit	(115)	(107)	(555)	(429)
Total share-based compensation, net	1,765	1,753	4,942	4,907
Cost of Sales [Member]
Allocated share-based compensation	125	123	408	327
Research and Development Expense [Member]
Allocated share-based compensation	354	278	1,098	856
Selling, General and Administrative Expenses [Member]
Allocated share-based compensation	$ 1,401	$ 1,459	$ 3,991	$ 4,153

Note 1 - Summary of Significa_7

Note 1 - Summary of Significant Accounting Policies - Computation of Basic and Diluted Income (Loss) Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Weighted average common shares (in shares)	28,948	28,155	28,814	27,614
Effect of dilutive securities (in shares)	822	950	836	1,026
(in shares)	29,770	29,105	29,650	28,640

Note 1 - Summary of Significa_8

Note 1 - Summary of Significant Accounting Policies - Cumulative-effect Adjustments (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 29, 2018		Sep. 30, 2017	Sep. 29, 2018		Sep. 30, 2017	Dec. 31, 2017	Dec. 30, 2017
Deferred profit		$ 1,894	[1]		$ 1,894	[1]		$ 5,350	$ 6,608
Income taxes payable		6,072			6,072			2,360	2,159	[2]
Retained earnings		171,110	[1]		171,110	[1]		151,783	$ 150,726	[2]
Net sales		86,164		$ 93,651	281,131		$ 268,614
Income tax provision		2,302		1,837	6,897		4,273
Net income		$ 4,803		$ 8,755	$ 24,573		$ 25,948
Basic: (in dollars per share)		$ 0.17		$ 0.31	$ 0.85		$ 0.94
Diluted: (in dollars per share)		$ 0.16		$ 0.30	$ 0.83		$ 0.91
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Deferred profit	[1]	$ 5,396			$ 5,396
Retained earnings	[1]	168,339			168,339
Net sales		86,820			279,038
Income tax provision		2,421			6,517
Net income		$ 5,340			$ 22,860
Basic: (in dollars per share)		$ 0.18			$ 0.79
Diluted: (in dollars per share)		$ 0.18			$ 0.77
Accounting Standards Update 2014-09 [Member]
Deferred profit								(1,258)
Income taxes payable								201
Retained earnings								$ 1,057
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Deferred profit	[1]	$ (3,502)			$ (3,502)
Retained earnings	[1]	2,771			2,771
Net sales		(656)			2,093
Income tax provision		(119)			380
Net income		$ (537)			$ 1,713
Basic: (in dollars per share)		$ (0.01)			$ 0.06
Diluted: (in dollars per share)		$ (0.02)			$ 0.06
[1]	Balance sheet line items include the cumulative-effect adjustment recorded on December 31, 2017.
[2]	Derived from December 30, 2017 audited financial statements

Note 1 - Summary of Significa_9

Note 1 - Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Net sales	$ 86,164	$ 93,651	$ 281,131	$ 268,614
CHINA
Net sales	23,628		63,011
UNITED STATES
Net sales	11,585		41,725
Malaysia [Member]
Net sales	13,682		38,539
PHILIPPINES
Net sales	11,158		31,620
Rest of the World [Member]
Net sales	26,111		106,236
Systems [Member]
Net sales	42,278		152,846
Non-systems [Member]
Net sales	$ 43,886		$ 128,285

Note 1 - Summary of Signific_10

Note 1 - Summary of Significant Accounting Policies - Customer Concentration (Details) - Sales Revenue, Net [Member] - Customer Concentration Risk [Member]	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Customers individually accounting for more than 10% of net sales	1	2	1	2
One Customer [Member]
Percentage of net sales	11.20%		10.80%
Two Customers [Member]
Percentage of net sales		26.50%		28.50%

Note 2 - Business Acquisition_3

Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Amortization of Intangible Assets, Total	$ 1,000	$ 1,100	$ 3,100	$ 3,200
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	$ 3,000	$ 3,000	3,000	3,000
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] | Selling, General and Administrative Expenses [Member]
Business Combination, Acquisition Related Costs			$ 0	$ 1,000

Note 2 - Business Acquisition_4

Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Total Purchase Price (Details) - Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] - USD ($) $ in Thousands	Jan. 04, 2017	Dec. 30, 2017
Cash paid to Kita shareholders	$ 15,000
Fair value of contingent consideration	823	$ 823
Total purchase price	$ 15,823

Note 2 - Business Acquisition_5

Note 2 - Business Acquisitions, Goodwill and Purchased Intangible Assets - Fair Value of Contingent Consideration (Details) - USD ($) $ in Thousands	Jan. 04, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 30, 2017
Mark-to-market adjustments charged to expense		$ 657	$ 668
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member]
Balance for contingent consideration		2,253
Fair value of contingent consideration	$ 823			823
Mark-to-market adjustments charged to expense		657		1,423
Impact of currency exchange		60		7
Settlement of contingent consideration		(1,500)
Balance for contingent consideration		$ 1,470		$ 2,253

Note 2 - Business Acquisition_6

Note 2 - Business Acquisitions, Goodwill and Other Purchased Intangible Assets - Changes in Carrying Value of Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 29, 2018		Dec. 30, 2017
Beginning balance	$ 65,613	[1]	$ 58,849
Additions, net			2,654
Impact of currency exchange	(1,034)		4,110
Ending balance	$ 64,579		$ 65,613	[1]
[1]	Derived from December 30, 2017 audited financial statements

Note 2 - Business Acquisitions

Note 2 - Business Acquisitions - Preliminary Allocation of Intangible Assets (Details) - Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Dec. 30, 2017
Gross carrying amount	$ 34,907	$ 35,212
Accumulated amortization	21,395	18,464
Developed Technology Rights [Member]
Gross carrying amount	20,632	20,780
Accumulated amortization	$ 14,468	12,623
Finite-lived intangible assets, average useful life (Year)	2 years 255 days
Customer Relationships [Member]
Gross carrying amount	$ 7,877	7,934
Accumulated amortization	$ 5,572	4,838
Finite-lived intangible assets, average useful life (Year)	2 years 109 days
Trade Names [Member]
Gross carrying amount	$ 6,088	6,185
Accumulated amortization	$ 1,301	972
Finite-lived intangible assets, average useful life (Year)	11 years 182 days
Noncompete Agreements [Member]
Gross carrying amount	$ 310	313
Accumulated amortization	$ 54	$ 31
Finite-lived intangible assets, average useful life (Year)	8 years 109 days

Note 3 - Financial Instrument_3

Note 3 - Financial Instruments Measured at Fair Value (Details Textual) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 0	$ 13,200

Note 3 - Financial Instrument_4

Note 3 - Financial Instruments Measured at Fair Value - Short-term Investments by Security Type (Details) - USD ($) $ in Thousands		Sep. 29, 2018	Dec. 30, 2017
Amortized Cost			$ 21,338
Gross Unrealized Gains			1
Gross Unrealized Losses	[1]		10
Short-term investments		$ 549	21,329	[2]
Debt Security, Government, Non-US [Member]
Amortized Cost		549	619
Gross Unrealized Gains
Gross Unrealized Losses	[1]
Short-term investments		$ 549	619
Corporate Debt Securities [Member]
Amortized Cost	[3]		12,784
Gross Unrealized Gains	[3]		1
Gross Unrealized Losses	[1],[3]		6
Short-term investments	[3]		12,779
US Treasury Securities [Member]
Amortized Cost			7,935
Gross Unrealized Gains
Gross Unrealized Losses	[1]		4
Short-term investments			$ 7,931
[1]	As of September 29, 2018, there were no investments in our portfolio in a loss position. As of December 30, 2017, the cost and fair value of investments with loss positions were approximately $13.2 million. We evaluated the nature of these investments, credit worthiness of the issuer and the duration of these impairments to determine if an other-than-temporary decline in fair value had occurred and concluded that these losses were temporary and we have the ability and intent to hold these investments to maturity.
[2]	Derived from December 30, 2017 audited financial statements
[3]	Corporate debt securities include investments in financial and other corporate institutions. No single issuer represents a significant portion of the total corporate debt securities portfolio.

Note 3 - Financial Instrument_5

Note 3 - Financial Instruments Measured at Fair Value - Effective Maturities of Short-term Investments (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Due in one year or less, amortized cost		$ 21,338
Due in one year or less, estimated fair value		21,329
Due after one year through three years, amortized cost	549
Due after one year through three years, fair value	549
Total amortized cost	549	21,338
Total estimated fair value	$ 549	$ 21,329

Note 3 - Financial Instrument_6

Note 3 - Financial Instruments Measured at Fair Value - Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
	$ 171,244	$ 155,615
Corporate Debt Securities [Member]
Short-term investments		22,014
Debt Security, Government, Non-US [Member]
Short-term investments	549	619
US Treasury Securities [Member]
Short-term investments		8,431
US Government-sponsored Enterprises Debt Securities [Member]
Short-term investments		1,496
Cash [Member]
Cash and cash equivalents	141,075	100,850
Money Market Funds [Member]
Cash and cash equivalents	29,620	22,205
Fair Value, Inputs, Level 1 [Member]
	141,075	100,850
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Short-term investments
Fair Value, Inputs, Level 1 [Member] | Debt Security, Government, Non-US [Member]
Short-term investments
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Short-term investments
Fair Value, Inputs, Level 1 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Short-term investments
Fair Value, Inputs, Level 1 [Member] | Cash [Member]
Cash and cash equivalents	141,075	100,850
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Cash and cash equivalents
Fair Value, Inputs, Level 2 [Member]
	30,169	54,765
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Short-term investments		22,014
Fair Value, Inputs, Level 2 [Member] | Debt Security, Government, Non-US [Member]
Short-term investments	549	619
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Short-term investments		8,431
Fair Value, Inputs, Level 2 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Short-term investments		1,496
Fair Value, Inputs, Level 2 [Member] | Cash [Member]
Cash and cash equivalents
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Cash and cash equivalents	29,620	22,205
Fair Value, Inputs, Level 3 [Member]
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Short-term investments
Fair Value, Inputs, Level 3 [Member] | Debt Security, Government, Non-US [Member]
Short-term investments
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Short-term investments
Fair Value, Inputs, Level 3 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Short-term investments
Fair Value, Inputs, Level 3 [Member] | Cash [Member]
Cash and cash equivalents
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Cash and cash equivalents

Note 4 - Employee Stock Benef_2

Note 4 - Employee Stock Benefit Plans (Details Textual) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 29, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	64,300
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance	407,926
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance | $ / shares	$ 10.24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value | $	$ 6.1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 328 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	407,926
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price | $ / shares	$ 10.24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value | $	$ 6.1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	3 years 328 days
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	286,709
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	432,031
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance	800,865
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding | $	$ 20.1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	1 year 109 days
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	88,418
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	40,640
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance	339,771
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding | $	$ 8.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	1 year 109 days
Equity Based Performance Stock Units Granted in 2018, 2017, and 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Equity Based Performance Stock Units Granted in 2018, 2017, and 2016 [Member] | Vest on the Third Anniversary of Awards Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	100.00%
Equity-based Performance Stock Units Granted in 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award, Performance Criteria Period	2 years
Equity-based Performance Stock Units Granted in 2015 [Member] | Vest on the Second and Third Anniversary of Awards Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	50.00%
Minimum [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Minimum [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Minimum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Shares Available for Issue	25.00%
Maximum [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Maximum [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Maximum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Shares Available for Issue	200.00%
Equity Incentive Plan 2005 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,204,761
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	559,646
Percentage of Fair Value to Determine Price of Common Stock	85.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans	41,694

Note 5 - Income Taxes (Details

Note 5 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Effective Income Tax Rate Reconciliation, Percent, Total	32.40%	17.30%	21.90%	14.00%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount	$ 600		$ 600
Unrecognized Tax Benefits, Period Increase (Decrease), Total	$ 0	$ 0	$ 0	$ 0

Note 7 - Guarantees and Other_3

Note 7 - Guarantees and Other Obligations (Details Textual) SFr in Millions	9 Months Ended
	Sep. 29, 2018USD ($)	Sep. 29, 2018CHF (SFr)	Dec. 30, 2017USD ($)
Loans Payable to Bank, Current	$ 1,021,000		$ 1,280,000	[1]
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] | Long-term Borrowings Assumed in Business Acquisition [Member]
Long-term Debt, Total	4,800,000
Loans Payable to Bank, Current	1,000,000
Revolving Credit Facility [Member] | Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member]
Line of Credit Facility, Maximum Borrowing Capacity	6,200,000
Long-term Line of Credit, Total	3,100,000
Line of Credit Available to Ismeca Subsidiary [Member]
Line of Credit Facility, Maximum Borrowing Capacity | SFr		SFr 2
Long-term Line of Credit, Total	0		0
Non-current Other Accrued Liabilities [Member]
Product Warranty Accrual, Noncurrent	$ 200,000		$ 600,000
Minimum [Member]
Standard Product Warranty Term	1 year
Minimum [Member] | Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] | Long-term Borrowings Assumed in Business Acquisition [Member]
Debt Instrument, Interest Rate, Stated Percentage	0.05%	0.05%
Maximum [Member]
Standard Product Warranty Term	3 years
Maximum [Member] | Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] | Long-term Borrowings Assumed in Business Acquisition [Member]
Debt Instrument, Interest Rate, Stated Percentage	0.45%	0.45%
[1]	Derived from December 30, 2017 audited financial statements

Note 7 - Guarantees and Other_4

Note 7 - Guarantees and Other Obligations - Changes in Accrued Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Balance at beginning of period	$ 4,948	$ 5,070	$ 4,848	$ 4,350
Warranty expense accruals	1,600	1,720	4,988	5,446
Warranty payments	(1,946)	(1,773)	(5,234)	(4,829)
Warranty liability assumed				50
Balance at end of period	$ 4,602	$ 5,017	$ 4,602	$ 5,017

Note 8 - Acquisition of Xcerra

Note 8 - Acquisition of Xcerra (Details Textual) - USD ($) $ / shares in Units, $ in Millions	Oct. 01, 2018	Sep. 29, 2018	Dec. 30, 2017	[1]
Common Stock, Par or Stated Value Per Share		$ 1	$ 1
Subsequent Event [Member]
Common Stock, Par or Stated Value Per Share	$ 1
Subsequent Event [Member] | Secured Term Loan Facility [Member]
Debt Instrument, Face Amount	$ 350
Debt Instrument, Amortization, Percentage of Principal Amount	0.25%
Debt Instrument, Prepayment Fee, Percentage	1.00%
Debt Instrument, Default Rate of Interest	2.00%
Debt Instrument, Incremental Facility Capacity, Aggregate Amount	$ 145
Debt Instrument, Incremental Facility Capacity, Percentage of Consolidated EBITDA	100.00%
Debt Instrument, Additional Borrowing Capacity	$ 35
Subsequent Event [Member] | Secured Term Loan Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	3.00%
Xcerra [Member] | Subsequent Event [Member]
Common Stock, Par or Stated Value Per Share	$ 0.05
Business Acquisition, Share Price	$ 9
Business Combination, Right to Receive, Per Share, Common Stock	0.2109
Xcerra [Member]
Business Combination, Acquisition Related Costs		$ 5.2
Xcerra [Member] | Subsequent Event [Member]
Payments to Acquire Businesses, Gross	$ 502.5
Xcerra [Member] | Subsequent Event [Member] | Common Stock [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	11,776,315
Xcerra [Member] | Subsequent Event [Member] | Cohu RSUs [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	530,000
Xcerra [Member] | Subsequent Event [Member] | Cash and Short-term Investments [Member]
Business Acquisition, Future Cash Amount	$ 70.5
[1]	Derived from December 30, 2017 audited financial statements