$COHU
COHU INC Stock $cohu

$cohu Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000143774921004277 Filed on February 26, 2021

Income Statement

Concept	2020 Q4	2020 Q3	2020 Q2
Revenue	$202.4M	$150.6M	$144.1M
YoY Change	42.49%	4.98%	-3.95%
Cost Of Revenue	$111.1M	$87.15M	$83.13M
YoY Change	26.36%	3.05%	-5.11%
Gross Profit	$91.24M	$63.50M	$60.96M
YoY Change	68.73%	7.75%	-2.32%
Gross Profit Margin	45.09%	42.15%	42.31%
Selling, General & Admin	$33.60M	$31.34M	$30.95M
YoY Change	-2.61%	-6.99%	-15.04%
% of Gross Profit	36.83%	49.35%	50.77%
Research & Development	$22.80M	$20.50M	$20.42M
YoY Change	9.62%	0.07%	-7.62%
% of Gross Profit	24.99%	32.28%	33.51%
Depreciation & Amortization	$13.47M	$13.24M	$13.08M
YoY Change	-0.37%	-12.95%	-13.38%
% of Gross Profit	14.76%	20.85%	21.46%
Operating Expenses	$66.30M	$51.83M	$51.37M
YoY Change	2.0%	-4.32%	-12.24%
Operating Profit	$24.94M	-$1.360M	-$528.0K
YoY Change	-328.29%	-77.42%	-96.4%
Interest Expense	-$3.500M	$3.021M	$3.456M
YoY Change	-40.68%	-39.58%	-34.57%
% of Operating Profit	-14.03%
Other Income/Expense, Net
YoY Change
Pretax Income	$15.30M	-$5.530M	-$4.603M
YoY Change	-178.46%	-39.91%	-77.32%
Income Tax	$400.0K	$1.116M	$137.0K
% Of Pretax Income	2.61%
Net Earnings	$14.86M	-$6.646M	-$4.740M
YoY Change	-186.07%	-36.51%	-75.47%
Net Earnings / Revenue	7.34%	-4.41%	-3.29%
Basic Earnings Per Share	$0.35	-$0.16	-$0.11
Diluted Earnings Per Share	$0.34	-$0.16	-$0.11
COMMON SHARES
Basic Shares Outstanding	41.97M	41.95M	41.84M
Diluted Shares Outstanding		41.95M	41.84M

Balance Sheet

Concept	2020 Q4	2020 Q3	2020 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$170.0M	$170.9M	$163.6M
YoY Change	8.9%	17.3%	13.93%
Cash & Equivalents	$149.4M	$169.9M	$162.7M
Short-Term Investments	$20.70M	$900.0K	$900.0K
Other Short-Term Assets	$1.827M	$1.273M	$953.0K
YoY Change	-42.15%	-52.3%	-16.7%
Inventory	$142.5M	$137.9M	$141.8M
Prepaid Expenses	$18.77M	$17.99M	$20.43M
Receivables	$151.9M	$116.8M	$122.5M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$485.0M	$444.8M	$456.3M
YoY Change	10.31%	3.06%	3.04%
LONG-TERM ASSETS
Property, Plant & Equipment	$66.92M	$64.55M	$65.81M
YoY Change	-5.64%	-8.37%	-8.32%
Goodwill	$252.3M	$244.3M	$239.0M
YoY Change	5.71%	3.58%	-1.04%
Intangibles	$233.7M	$238.8M	$252.2M
YoY Change	-15.03%	-15.45%	-15.14%
Long-Term Investments
YoY Change
Other Assets	$23.19M	$23.72M	$21.90M
YoY Change	15.79%	39.86%	46.45%
Total Long-Term Assets	$605.3M	$601.5M	$610.3M
YoY Change	-5.13%	-6.01%	-7.62%
TOTAL ASSETS
Total Short-Term Assets	$485.0M	$444.8M	$456.3M
Total Long-Term Assets	$605.3M	$601.5M	$610.3M
Total Assets	$1.090B	$1.046B	$1.067B
YoY Change	1.17%	-2.36%	-3.35%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$67.92M	$49.37M	$60.01M
YoY Change	39.48%	2.58%	10.21%
Accrued Expenses	$71.00M	$61.40M	$55.50M
YoY Change	-10.13%	-9.04%	-21.94%
Deferred Revenue	$14.41M	$11.12M	$17.75M
YoY Change	18.5%	-31.38%	6.28%
Short-Term Debt	$5.300M	$5.200M	$4.700M
YoY Change	65.63%	62.5%	46.88%
Long-Term Debt Due	$8.389M	$8.199M	$7.919M
YoY Change	28.72%	28.47%	22.07%
Total Short-Term Liabilities	$174.5M	$146.9M	$159.0M
YoY Change	17.17%	5.42%	8.24%
LONG-TERM LIABILITIES
Long-Term Debt	$311.6M	$331.5M	$348.0M
YoY Change	-10.09%	-3.9%	1.77%
Other Long-Term Liabilities	$63.00M	$64.30M	$64.90M
YoY Change	-7.22%	-2.72%	-1.52%
Total Long-Term Liabilities	$311.6M	$331.5M	$348.0M
YoY Change	-10.09%	-3.9%	1.77%
TOTAL LIABILITIES
Total Short-Term Liabilities	$174.5M	$146.9M	$159.0M
Total Long-Term Liabilities	$311.6M	$331.5M	$348.0M
Total Liabilities	$486.0M	$478.4M	$507.1M
YoY Change	-1.9%	-1.22%	3.72%
SHAREHOLDERS EQUITY
Retained Earnings	$26.23M	$11.37M	$18.02M
YoY Change	-38.31%	-81.76%	-76.02%
Common Stock	$490.4M	$484.6M	$481.8M
YoY Change	3.33%	3.18%	3.23%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$0.00
YoY Change
Treasury Stock Shares	$0.00
Shareholders Equity	$512.3M	$474.6M	$466.8M
YoY Change
Total Liabilities & Shareholders Equity	$1.090B	$1.046B	$1.067B
YoY Change	1.17%	-2.36%	-3.35%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2020 Q2
OPERATING ACTIVITIES
Net Income	$14.86M	-$6.646M	-$4.740M
YoY Change	-186.07%	-36.51%	-75.47%
Depreciation, Depletion And Amortization	$13.47M	$13.24M	$13.08M
YoY Change	-0.37%	-12.95%	-13.38%
Cash From Operating Activities	$21.71M	$14.73M	-$4.520M
YoY Change	56.98%	79.42%	-52.37%
INVESTING ACTIVITIES
Capital Expenditures	-$5.100M	-$5.600M	-$6.380M
YoY Change	9.68%	13.13%	31.01%
Acquisitions
YoY Change
Other Investing Activities	-$19.66M	$14.46M	$2.450M
YoY Change	27985.71%	1936.62%	206.25%
Cash From Investing Activities	-$24.76M	$8.860M	-$3.930M
YoY Change	424.58%	-308.96%	-3.44%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-18.51M	-16.98M	-330.0K
YoY Change	-6955.56%	-11420.0%	-90.03%
NET CHANGE
Cash From Operating Activities	21.71M	14.73M	-4.520M
Cash From Investing Activities	-24.76M	8.860M	-3.930M
Cash From Financing Activities	-18.51M	-16.98M	-330.0K
Net Change In Cash	-21.56M	6.610M	-8.780M
YoY Change	-329.85%	60.44%	-47.95%
FREE CASH FLOW
Cash From Operating Activities	$21.71M	$14.73M	-$4.520M
Capital Expenditures	-$5.100M	-$5.600M	-$6.380M
Free Cash Flow	$26.81M	$20.33M	$1.860M
YoY Change	45.08%	54.48%	-140.26%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0
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CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	149358000	USD
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CY2020Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	34862000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	23741000	USD
CY2020Q4	us-gaap	Product Warranty Accrual Classified Current ProductWarrantyAccrualClassifiedCurrent	6066000	USD
CY2019Q4	us-gaap	Product Warranty Accrual Classified Current ProductWarrantyAccrualClassifiedCurrent	5893000	USD
CY2020Q4	cohu	Deferred Profit DeferredProfit	8671000	USD
CY2019Q4	cohu	Deferred Profit DeferredProfit	7645000	USD
CY2020Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	3857000	USD
CY2020Q4	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	20669000	USD
CY2019Q4	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	904000	USD
CY2020Q4	us-gaap	Accounts And Other Receivables Net Current AccountsAndOtherReceivablesNetCurrent	151919000	USD
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CY2020Q4	us-gaap	Inventory Net InventoryNet	142500000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	130706000	USD
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CY2019Q4	us-gaap	Other Assets Current OtherAssetsCurrent	3158000	USD
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CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	666000	USD
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CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	42000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-697000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	119000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	-13801000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	-69692000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	-32424000	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	8000	USD
CY2018	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-243000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-13801000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	-69700000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	-32181000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.33
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-1.68
CY2018	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-1.02
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.01
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2020	cohu	Net Income Loss Attributable To Noncontrolling Interest Per Basic Share NetIncomeLossAttributableToNoncontrollingInterestPerBasicShare	-0
CY2019	cohu	Net Income Loss Attributable To Noncontrolling Interest Per Basic Share NetIncomeLossAttributableToNoncontrollingInterestPerBasicShare	-0.00
CY2018	cohu	Net Income Loss Attributable To Noncontrolling Interest Per Basic Share NetIncomeLossAttributableToNoncontrollingInterestPerBasicShare	0.01
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.33
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-1.69
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-1.01
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.33
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-1.68
CY2018	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-1.02
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.01
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	409000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2020	cohu	Net Income Loss Attributable To Noncontrolling Interest Per Diluted Share NetIncomeLossAttributableToNoncontrollingInterestPerDilutedShare	-0
CY2019	cohu	Net Income Loss Attributable To Noncontrolling Interest Per Diluted Share NetIncomeLossAttributableToNoncontrollingInterestPerDilutedShare	-0.00
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	545944000	USD
CY2019	us-gaap	Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest	-69692000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-7526000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	628000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	9866000	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	8000	USD
CY2018	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-243000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-13801000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	-69700000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	-32181000	USD
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	27321000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-7522000	USD
CY2018	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-8905000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-2383000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	628000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-805000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	0	USD
CY2018	cohu	Net Income Loss Attributable To Noncontrolling Interest Per Diluted Share NetIncomeLossAttributableToNoncontrollingInterestPerDilutedShare	0.01
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.33
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-1.69
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-1.01
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	41854000
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	41159000
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	31776000
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41854000
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41159000
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	31776000
CY2020	us-gaap	Profit Loss ProfitLoss	-13801000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	-69692000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	-32424000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	7000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	29704000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8150000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8093000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-4000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-5000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	29704000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-8146000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-8088000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	15903000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-77842000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-40517000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	4000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-248000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	15903000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-77846000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-40269000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	289091000	USD
CY2018	us-gaap	Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest	-32424000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-8905000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-805000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	7000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	7689000	USD
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	680000	USD
CY2018	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	1523000	USD
CY2018	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2018	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	11600000	USD
CY2018	us-gaap	Minority Interest Period Increase Decrease MinorityInterestPeriodIncreaseDecrease	-299000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	18280000	USD
CY2018	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	295418000	USD
CY2019	cohu	Sharebased Compensation Expense Including Restructuring Charges SharebasedCompensationExpenseIncludingRestructuringCharges	14148000	USD
CY2018	cohu	Sharebased Compensation Expense Including Restructuring Charges SharebasedCompensationExpenseIncludingRestructuringCharges	18279000	USD
CY2020	cohu	Amortization Of Inventory Stepup And Inventory Related Charges AmortizationOfInventoryStepupAndInventoryRelatedCharges	3731000	USD
CY2019	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2346000	USD
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2019	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	2771000	USD
CY2019	us-gaap	Minority Interest Period Increase Decrease MinorityInterestPeriodIncreaseDecrease	0	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	14148000	USD
CY2019	us-gaap	Noncontrolling Interest Decrease From Deconsolidation NoncontrollingInterestDecreaseFromDeconsolidation	356000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	483072000	USD
CY2020	us-gaap	Net Income Loss Including Portion Attributable To Nonredeemable Noncontrolling Interest NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest	-13801000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	27321000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-2383000	USD
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	2486000	USD
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	1102000	USD
CY2020	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	3269000	USD
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2020	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	2806000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	14234000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	512288000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-13801000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	-69700000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	-32181000	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	8000	USD
CY2018	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-243000	USD
CY2020	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	35000	USD
CY2019	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	-1138000	USD
CY2018	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	-0	USD
CY2020	cohu	Interest Capitalized Associated With Cloud Computing Implementation InterestCapitalizedAssociatedWithCloudComputingImplementation	124000	USD
CY2019	cohu	Interest Capitalized Associated With Cloud Computing Implementation InterestCapitalizedAssociatedWithCloudComputingImplementation	168000	USD
CY2018	cohu	Interest Capitalized Associated With Cloud Computing Implementation InterestCapitalizedAssociatedWithCloudComputingImplementation	-0	USD
CY2020	us-gaap	Deconsolidation Gain Or Loss Amount DeconsolidationGainOrLossAmount	-0	USD
CY2019	us-gaap	Deconsolidation Gain Or Loss Amount DeconsolidationGainOrLossAmount	149000	USD
CY2018	us-gaap	Deconsolidation Gain Or Loss Amount DeconsolidationGainOrLossAmount	-0	USD
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	268000	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-0	USD
CY2018	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-0	USD
CY2020	us-gaap	Impairment Of Intangible Assets Indefinitelived Excluding Goodwill ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill	11249000	USD
CY2019	us-gaap	Impairment Of Intangible Assets Indefinitelived Excluding Goodwill ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill	0	USD
CY2018	us-gaap	Impairment Of Intangible Assets Indefinitelived Excluding Goodwill ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill	0	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	52746000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	58871000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	26047000	USD
CY2020	cohu	Sharebased Compensation Expense Including Restructuring Charges SharebasedCompensationExpenseIncludingRestructuringCharges	14234000	USD
CY2019	cohu	Amortization Of Inventory Stepup And Inventory Related Charges AmortizationOfInventoryStepupAndInventoryRelatedCharges	8347000	USD
CY2018	cohu	Amortization Of Inventory Stepup And Inventory Related Charges AmortizationOfInventoryStepupAndInventoryRelatedCharges	24179000	USD
CY2020	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	1177000	USD
CY2019	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	1110000	USD
CY2018	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	0	USD
CY2020	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	1675000	USD
CY2019	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	1017000	USD
CY2018	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	-560000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5305000	USD
CY2018	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	198000	USD
CY2020	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	2188000	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	11548000	USD
CY2018	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	2513000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	20210000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-21150000	USD
CY2019	cohu	Increase Decrease In Operating Lease Right Of Use Assets IncreaseDecreaseInOperatingLeaseRightOfUseAssets	-7159000	USD
CY2018	cohu	Increase Decrease In Operating Lease Right Of Use Assets IncreaseDecreaseInOperatingLeaseRightOfUseAssets	-0	USD
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-5785000	USD
CY2020	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	14982000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-26000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-2043000	USD
CY2020	cohu	Increase Decrease In Accrued Compensation Warranty And Other Liabilities IncreaseDecreaseInAccruedCompensationWarrantyAndOtherLiabilities	4678000	USD
CY2019	cohu	Increase Decrease In Accrued Compensation Warranty And Other Liabilities IncreaseDecreaseInAccruedCompensationWarrantyAndOtherLiabilities	-9405000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5385000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-8207000	USD
CY2020	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	0	USD
CY2019	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	0	USD
CY2018	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	657000	USD
CY2020	us-gaap	Increase Decrease In Other Noncurrent Assets IncreaseDecreaseInOtherNoncurrentAssets	-285000	USD
CY2019	us-gaap	Increase Decrease In Other Noncurrent Assets IncreaseDecreaseInOtherNoncurrentAssets	3044000	USD
CY2018	us-gaap	Increase Decrease In Other Noncurrent Assets IncreaseDecreaseInOtherNoncurrentAssets	2961000	USD
CY2020	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	1191000	USD
CY2019	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	0	USD
CY2018	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	0	USD
CY2020	us-gaap	Gain Loss On Sales Of Assets And Asset Impairment Charges GainLossOnSalesOfAssetsAndAssetImpairmentCharges	4170000	USD
CY2019	us-gaap	Gain Loss On Sales Of Assets And Asset Impairment Charges GainLossOnSalesOfAssetsAndAssetImpairmentCharges	-173000	USD
CY2018	us-gaap	Gain Loss On Sales Of Assets And Asset Impairment Charges GainLossOnSalesOfAssetsAndAssetImpairmentCharges	-293000	USD
CY2020	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	91000	USD
CY2019	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	5348000	USD
CY2018	cohu	Increase Decrease In Accrued Compensation Warranty And Other Liabilities IncreaseDecreaseInAccruedCompensationWarrantyAndOtherLiabilities	1472000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	15058000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-3122000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-7103000	USD
CY2020	cohu	Increase Decrease In Deferred Profit IncreaseDecreaseInDeferredProfit	871000	USD
CY2019	cohu	Increase Decrease In Deferred Profit IncreaseDecreaseInDeferredProfit	997000	USD
CY2018	cohu	Increase Decrease In Deferred Profit IncreaseDecreaseInDeferredProfit	37000	USD
CY2020	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-1150000	USD
CY2019	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	5996000	USD
CY2018	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-148000	USD
CY2020	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-2089000	USD
CY2019	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-10719000	USD
CY2018	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	4041000	USD
CY2020	cohu	Increase Decrease In Operating Lease Right Of Use Assets IncreaseDecreaseInOperatingLeaseRightOfUseAssets	-6831000	USD
CY2020	cohu	Increase Decrease In Current And Noncurrent Operating Lease Liabilities IncreaseDecreaseInCurrentAndNoncurrentOperatingLeaseLiabilities	-6437000	USD
CY2019	cohu	Increase Decrease In Current And Noncurrent Operating Lease Liabilities IncreaseDecreaseInCurrentAndNoncurrentOperatingLeaseLiabilities	-6083000	USD
CY2018	cohu	Increase Decrease In Current And Noncurrent Operating Lease Liabilities IncreaseDecreaseInCurrentAndNoncurrentOperatingLeaseLiabilities	0	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	49734000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	17269000	USD
CY2018	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	339115000	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	0	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	34437000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	18660000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	18000000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	4967000	USD
CY2020	us-gaap	Sale Leaseback Transaction Net Proceeds Investing Activities SaleLeasebackTransactionNetProceedsInvestingActivities	17025000	USD
CY2019	us-gaap	Sale Leaseback Transaction Net Proceeds Investing Activities SaleLeasebackTransactionNetProceedsInvestingActivities	1767000	USD
CY2018	us-gaap	Sale Leaseback Transaction Net Proceeds Investing Activities SaleLeasebackTransactionNetProceedsInvestingActivities	1005000	USD
CY2020	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	19703000	USD
CY2019	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	315000	USD
CY2018	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	38700000	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-0	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-0	USD
CY2019Q4	us-gaap	Disposal Group Including Discontinued Operation Cash DisposalGroupIncludingDiscontinuedOperationCash	736000	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	0	USD
CY2018	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	59469000	USD
CY2020	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	2975000	USD
CY2019	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	0	USD
CY2018	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	0	USD
CY2020	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-18363000	USD
CY2019	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-16548000	USD
CY2018	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-322308000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	4971000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	9827000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6949000	USD
CY2020	us-gaap	Proceeds From Construction Loans Payable ProceedsFromConstructionLoansPayable	5878000	USD
CY2019	us-gaap	Proceeds From Construction Loans Payable ProceedsFromConstructionLoansPayable	5477000	USD
CY2018	us-gaap	Proceeds From Construction Loans Payable ProceedsFromConstructionLoansPayable	0	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	41056000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	3817000	USD
CY2018	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	2323000	USD
CY2020	us-gaap	Proceeds From Repurchase Of Equity ProceedsFromRepurchaseOfEquity	2077000	USD
CY2019	us-gaap	Proceeds From Repurchase Of Equity ProceedsFromRepurchaseOfEquity	-16000	USD
CY2018	us-gaap	Proceeds From Repurchase Of Equity ProceedsFromRepurchaseOfEquity	-8978000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	348250000	USD
CY2020	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	-0	USD
CY2019	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	-0	USD
CY2018	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	7072000	USD
CY2020	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	-0	USD
CY2019	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	-0	USD
CY2018	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	823000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-38072000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-8183000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	322105000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	129000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	-1529000	USD
CY2018	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	-3599000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-6572000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-8991000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	30635000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	155930000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	164921000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	134286000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	149358000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	155930000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	164921000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Cash DisposalGroupIncludingDiscontinuedOperationCash	-0	USD
CY2018Q4	us-gaap	Disposal Group Including Discontinued Operation Cash DisposalGroupIncludingDiscontinuedOperationCash	461000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	41854000
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	149358000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	155194000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	164460000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	5772000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	14942000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	6243000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	16324000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	14846000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	4977000	USD
CY2020Q4	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	0	USD
CY2019Q4	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	2484000	USD
CY2018Q4	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	2445000	USD
CY2020	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	1063000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	1601000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	599000	USD
CY2020	cohu	Inventory Capitalized As Property Plant And Equipment InventoryCapitalizedAsPropertyPlantAndEquipment	1050000	USD
CY2019	cohu	Inventory Capitalized As Property Plant And Equipment InventoryCapitalizedAsPropertyPlantAndEquipment	300000	USD
CY2018	cohu	Inventory Capitalized As Property Plant And Equipment InventoryCapitalizedAsPropertyPlantAndEquipment	857000	USD
CY2020	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	113000
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	422000
CY2018	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	146000
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	41159000
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	31776000
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2019Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	46591000	USD
CY2019Q4	us-gaap	Inventory Raw Materials And Supplies Net Of Reserves InventoryRawMaterialsAndSuppliesNetOfReserves	69665000	USD
CY2020Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	44315000	USD
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2018	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41854000
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41159000
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	31776000
CY2020	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin-bottom:0pt;margin-left:18pt;margin-right:0pt;margin-top:0pt;text-align:left;"><b>Concentration of Credit Risk</b> – 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 <em style="font: inherit;">one</em> issuer.</p> <p style="font-family: 'Times New Roman', Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;"> </p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin-bottom:0pt;margin-left:18pt;margin-right:0pt;margin-top:0pt;text-align:left;">We adopted ASU <em style="font: inherit;">2016</em>-<em style="font: inherit;">13</em><i>, Financial Instruments-Credit Losses (Topic <em style="font: inherit;">326</em>): Measurement of Credit Losses on Financial Instruments</i>, on <em style="font: inherit;"> December 29, 2019 </em>the <em style="font: inherit;">first</em> day of our fiscal <em style="font: inherit;">2020.</em> The ASU required a cumulative-effect adjustment to the statement of financial position as of the date of adoption. Periods prior to the adoption that are presented for comparative purposes are <em style="font: inherit;">not</em> adjusted. Based on our analysis of historical and anticipated collections of trade receivables the impact of adoption of Topic <em style="font: inherit;">326</em> was insignificant. Our trade accounts receivable are presented net of allowance for credit losses, which were insignificant at <em style="font: inherit;"> December 26, 2020 </em>and <em style="font: inherit;"> December 28, 2019. </em>Our customers include semiconductor manufacturers and semiconductor test subcontractors throughout many areas of the world. While we believe that our allowance for credit losses is adequate and represents our best estimate at <em style="font: inherit;"> December 26, 2020, </em>we will continue to monitor customer liquidity and other economic conditions, including the impact of the COVID-<em style="font: inherit;">19</em> pandemic, which <em style="font: inherit;"> may </em>result in changes to our estimates regarding expected credit losses.</p> <p style="font-family: 'Times New Roman', Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;"> </p>
CY2020	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	8100000	USD
CY2019	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	4800000	USD
CY2018	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	10800000	USD
CY2020Q4	us-gaap	Inventory Raw Materials And Supplies Net Of Reserves InventoryRawMaterialsAndSuppliesNetOfReserves	83755000	USD
CY2020Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	14430000	USD
CY2019Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	14450000	USD
CY2020Q4	us-gaap	Inventory Net InventoryNet	142500000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	130706000	USD
CY2020	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	4500000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	114636000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	114139000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	47720000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	43227000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	66916000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	70912000	USD
CY2020	us-gaap	Depreciation Depreciation	14000000.0	USD
CY2019	us-gaap	Depreciation Depreciation	19300000	USD
CY2018	us-gaap	Depreciation Depreciation	8800000	USD
CY2020Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	13500000	USD
CY2019Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	10300000	USD
CY2020	us-gaap	Capitalized Computer Software Amortization1 CapitalizedComputerSoftwareAmortization1	1200000	USD
CY2020Q4	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	17100000	USD
CY2019Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	16100000	USD
CY2020Q4	us-gaap	Deferred Revenue DeferredRevenue	17100000	USD
CY2020Q4	cohu	Deferred Profit DeferredProfit	8700000	USD
CY2020Q4	cohu	Deferred Profit Longterm DeferredProfitLongterm	6700000	USD
CY2019Q4	us-gaap	Deferred Revenue DeferredRevenue	16100000	USD
CY2019Q4	cohu	Deferred Profit DeferredProfit	7600000	USD
CY2019Q4	cohu	Deferred Profit Longterm DeferredProfitLongterm	7200000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	636007000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	583329000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	451768000	USD
CY2020	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	1200000	USD
CY2019	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	1100000	USD
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	-3200000	USD
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Realized ForeignCurrencyTransactionGainLossRealized	1700000	USD
CY2019	us-gaap	Goodwill Purchase Accounting Adjustments GoodwillPurchaseAccountingAdjustments	1134000	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	715000	USD
CY2019	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-3877000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-4300000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-34000000.0	USD
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	27300000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax	-7500000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	242127000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	238669000	USD
CY2020	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	13635000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	252304000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	338279000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	112412000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	322804000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	68617000	USD
CY2020	cohu	Transfer From In Process Technology To Developed Technology TransferFromInProcessTechnologyToDevelopedTechnology	1800000	USD
CY2020	us-gaap	Impairment Of Intangible Assets Indefinitelived Excluding Goodwill ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill	11200000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	38700000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	39600000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	17200000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	36400000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	36400000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	36300000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	36300000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	27100000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	53500000	USD
CY2020Q4	us-gaap	Line Of Credit LineOfCredit	5314000	USD
CY2019Q4	us-gaap	Line Of Credit LineOfCredit	3195000	USD
CY2020Q4	cohu	Debt Longterm And Shortterm Combined Amount Gross DebtLongtermAndShorttermCombinedAmountGross	325508000	USD
CY2019Q4	cohu	Debt Longterm And Shortterm Combined Amount Gross DebtLongtermAndShorttermCombinedAmountGross	360476000	USD
CY2020Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	5568000	USD
CY2019Q4	us-gaap	Debt Instrument Unamortized Discount Premium And Debt Issuance Costs Net DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	7441000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	8389000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	6517000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	311551000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	346518000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	9512000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	4720000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	4725000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	4730000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	293864000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	7957000	USD
CY2020Q4	us-gaap	Long Term Debt LongTermDebt	325508000	USD
CY2020Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	303100000	USD
CY2020	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent Of Match DefinedContributionPlanEmployerMatchingContributionPercentOfMatch	0.50	pure
CY2020	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent DefinedContributionPlanEmployerMatchingContributionPercent	0.08	pure
CY2020	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	2300000	USD
CY2019	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	2000000.0	USD
CY2018	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	1100000	USD
CY2020Q4	us-gaap	Deferred Compensation Liability Current DeferredCompensationLiabilityCurrent	1800000	USD
CY2020Q4	us-gaap	Cash Surrender Value Of Life Insurance CashSurrenderValueOfLifeInsurance	1800000	USD
CY2019Q4	us-gaap	Deferred Compensation Liability Current DeferredCompensationLiabilityCurrent	2000000.0	USD
CY2019Q4	us-gaap	Cash Surrender Value Of Life Insurance CashSurrenderValueOfLifeInsurance	1700000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	363000
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	10.27
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	405000
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	10.22
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	472000
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	10.20
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	101000
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	10.95
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	42000
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	9.82
CY2018	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	67000
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	10.10
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	262000
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	10.01
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	363000
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	10.27
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	405000
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	10.22
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	262000
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	10.01
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	363000
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	10.27
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	405000
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	10.22
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	1300000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	200000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	900000	USD
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	7500000	USD
CY2020Q4	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Number Of Outstanding Options ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions	262000
CY2020	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Term2 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2	P1Y10M24D
CY2020Q4	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Exercise Price Beginning Balance1 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1	10.01
CY2020Q4	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Number Of Exercisable Options ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions	262000
CY2020Q4	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Exercisable Options Weighted Average Exercise Price1 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1	10.01
CY2020	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	13271000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	13561000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	14234000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	14148000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10053000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	963000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	587000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	993000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	9060000	USD
CY2020Q4	us-gaap	Available For Sale Securities Amortized Cost AvailableForSaleSecuritiesAmortizedCost	20668000	USD
CY2020Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	2000	USD
CY2020Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1000	USD
CY2020Q4	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	20669000	USD
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	8700000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	20668000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	20669000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5385000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-8207000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	21000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	130000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	51000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	5950000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	2173000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	8787000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	5971000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	2303000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	8838000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	8000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	98000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	56000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	0	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	1000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	0	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-5313000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-5484000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-8263000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5305000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	666000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-3082000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	631000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-25005000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-72669000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-42682000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	11828000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	592000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	10770000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-13177000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-72077000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-31912000	USD
CY2017	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	16600000	USD
CY2018	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	5100000	USD
CY2017	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	-4000000.0	USD
CY2020Q4	cohu	Deferred Tax Assets Inventory And Warranty Reserves DeferredTaxAssetsInventoryAndWarrantyReserves	11720000	USD
CY2019Q4	cohu	Deferred Tax Assets Inventory And Warranty Reserves DeferredTaxAssetsInventoryAndWarrantyReserves	11235000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	56777000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	69092000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	37393000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	36489000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	5306000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	4274000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	2210000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	2372000	USD
CY2020Q4	cohu	Deferred Tax Assets Lease Liabilities DeferredTaxAssetsLeaseLiabilities	5146000	USD
CY2019Q4	cohu	Deferred Tax Assets Lease Liabilities DeferredTaxAssetsLeaseLiabilities	5804000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	4221000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	9390000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	122773000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	138656000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	86124000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	93494000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	36649000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	45162000	USD
CY2020Q4	cohu	Deferred Tax Liabilities Asset Basis Differences DeferredTaxLiabilitiesAssetBasisDifferences	52012000	USD
CY2019Q4	cohu	Deferred Tax Liabilities Asset Basis Differences DeferredTaxLiabilitiesAssetBasisDifferences	63866000	USD
CY2020Q4	cohu	Deferred Tax Liabilities Operating Lease Rightofuse Assets DeferredTaxLiabilitiesOperatingLeaseRightofuseAssets	4706000	USD
CY2019Q4	cohu	Deferred Tax Liabilities Operating Lease Rightofuse Assets DeferredTaxLiabilitiesOperatingLeaseRightofuseAssets	5258000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	3119000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	2462000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	59837000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	71586000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	23188000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-258000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	666000	USD
CY2020	us-gaap	Interest Expense InterestExpense	13759000	USD
CY2019	us-gaap	Interest Expense InterestExpense	20556000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	26424000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	86100000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	93500000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-2757000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-15136000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-6702000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	5095000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-1160000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-1097000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-663000	USD
CY2020	cohu	Income Tax Reconciliation Settlements Adjustments And Releases From Statute Expirations IncomeTaxReconciliationSettlementsAdjustmentsAndReleasesFromStatuteExpirations	-118000	USD
CY2019	cohu	Income Tax Reconciliation Settlements Adjustments And Releases From Statute Expirations IncomeTaxReconciliationSettlementsAdjustmentsAndReleasesFromStatuteExpirations	-1204000	USD
CY2018	cohu	Income Tax Reconciliation Settlements Adjustments And Releases From Statute Expirations IncomeTaxReconciliationSettlementsAdjustmentsAndReleasesFromStatuteExpirations	-783000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	46000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	1458000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	864000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	727000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	587000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-838000	USD
CY2020	cohu	Effective Income Tax Rate Reconciliation Limited Executive Compensation Amount EffectiveIncomeTaxRateReconciliationLimitedExecutiveCompensationAmount	491000	USD
CY2019	cohu	Effective Income Tax Rate Reconciliation Limited Executive Compensation Amount EffectiveIncomeTaxRateReconciliationLimitedExecutiveCompensationAmount	190000	USD
CY2018	cohu	Effective Income Tax Rate Reconciliation Limited Executive Compensation Amount EffectiveIncomeTaxRateReconciliationLimitedExecutiveCompensationAmount	3456000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-1691000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	11270000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-2015000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	0	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	0	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	1106000	USD
CY2020	cohu	Effective Income Tax Rate Reconciliation Deemed Dividends Amount EffectiveIncomeTaxRateReconciliationDeemedDividendsAmount	1224000	USD
CY2019	cohu	Effective Income Tax Rate Reconciliation Deemed Dividends Amount EffectiveIncomeTaxRateReconciliationDeemedDividendsAmount	1453000	USD
CY2018	cohu	Effective Income Tax Rate Reconciliation Deemed Dividends Amount EffectiveIncomeTaxRateReconciliationDeemedDividendsAmount	470000	USD
CY2020	cohu	Effective Income Tax Rate Reconciliation Gilti Amount EffectiveIncomeTaxRateReconciliationGILTIAmount	4191000	USD
CY2019	cohu	Effective Income Tax Rate Reconciliation Gilti Amount EffectiveIncomeTaxRateReconciliationGILTIAmount	2480000	USD
CY2018	cohu	Effective Income Tax Rate Reconciliation Gilti Amount EffectiveIncomeTaxRateReconciliationGILTIAmount	3531000	USD
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-1512000	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-1266000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-904000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	1317000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	1099000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-3082000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	631000	USD
CY2020	cohu	Increase Decrease Of Net Income Due To Impact Of Tax Holidays IncreaseDecreaseOfNetIncomeDueToImpactOfTaxHolidays	3600000	USD
CY2020Q4	us-gaap	Decrease In Unrecognized Tax Benefits Is Reasonably Possible DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible	600000	USD
CY2020	cohu	Increase Decrease Of Earning Per Share Due To Impact Of Tax Holidays IncreaseDecreaseOfEarningPerShareDueToImpactOfTaxHolidays	0.09
CY2019	cohu	Increase Decrease Of Net Income Due To Impact Of Tax Holidays IncreaseDecreaseOfNetIncomeDueToImpactOfTaxHolidays	2100000	USD
CY2019	cohu	Increase Decrease Of Earning Per Share Due To Impact Of Tax Holidays IncreaseDecreaseOfEarningPerShareDueToImpactOfTaxHolidays	0.05
CY2018	cohu	Increase Decrease Of Net Income Due To Impact Of Tax Holidays IncreaseDecreaseOfNetIncomeDueToImpactOfTaxHolidays	2400000	USD
CY2018	cohu	Increase Decrease Of Earning Per Share Due To Impact Of Tax Holidays IncreaseDecreaseOfEarningPerShareDueToImpactOfTaxHolidays	0.08
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	34740000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	34873000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	10321000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	817000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1231000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	524000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	425000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	484000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	191000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	304000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	957000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	645000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	24524000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	1134000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	30000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	-0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Foreign Currency Translation UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation	2000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Foreign Currency Translation UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation	107000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Foreign Currency Translation UnrecognizedTaxBenefitsDecreasesResultingFromForeignCurrencyTranslation	42000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	33696000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	34740000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	34873000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	5700000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	7000000.0	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	8200000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	1000000.0	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	1300000	USD
CY2020	cohu	Unrecognized Tax Benefits Interest Expense Net Of Accrued Interest Reversed UnrecognizedTaxBenefitsInterestExpenseNetOfAccruedInterestReversed	-300000	USD
CY2019	cohu	Unrecognized Tax Benefits Interest Expense Net Of Accrued Interest Reversed UnrecognizedTaxBenefitsInterestExpenseNetOfAccruedInterestReversed	-300000	USD
CY2018	cohu	Unrecognized Tax Benefits Interest Expense Net Of Accrued Interest Reversed UnrecognizedTaxBenefitsInterestExpenseNetOfAccruedInterestReversed	600000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	636007000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	583329000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	451768000	USD
CY2020	cohu	Profit Loss From Operating Segment ProfitLossFromOperatingSegment	4474000	USD
CY2019	cohu	Profit Loss From Operating Segment ProfitLossFromOperatingSegment	-42437000	USD
CY2018	cohu	Profit Loss From Operating Segment ProfitLossFromOperatingSegment	-2665000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	40844000	USD
CY2018	us-gaap	Interest Expense InterestExpense	4977000	USD
CY2020	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	224000	USD
CY2019	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	764000	USD
CY2018	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	1187000	USD
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	268000	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2018	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-13177000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-72077000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-31912000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	52746000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	58871000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	26047000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	18660000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	18000000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	4967000	USD
CY2020Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation AssetsOfDisposalGroupIncludingDiscontinuedOperation	0	USD
CY2019Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation AssetsOfDisposalGroupIncludingDiscontinuedOperation	3618000	USD
CY2018Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation AssetsOfDisposalGroupIncludingDiscontinuedOperation	3820000	USD
CY2020Q4	us-gaap	Assets Assets	1090346000	USD
CY2019Q4	us-gaap	Assets Assets	1077710000	USD
CY2018Q4	us-gaap	Assets Assets	1134002000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	636007000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	583329000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	451768000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	66916000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	70912000	USD
CY2020Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	485989000	USD
CY2019Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	513688000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P25Y
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	29203000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	33269000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	486000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	2515000	USD
CY2020Q4	cohu	Lease Rightofuse Asset LeaseRightofuseAsset	29689000	USD
CY2019Q4	cohu	Lease Rightofuse Asset LeaseRightofuseAsset	35784000	USD
CY2020Q4	cohu	Lease Liability LeaseLiability	31253000	USD
CY2019Q4	cohu	Lease Liability LeaseLiability	36909000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y3M18D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y10M24D
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P2Y3M18D
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P0Y6M
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.063	pure
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.063	pure
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.000	pure
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.045	pure
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	48000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	100000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	8374000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	8525000	USD
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	2110000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	2318000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	93000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	256000	USD
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	84000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	102000	USD
CY2020	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	57000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	146000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	113000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	133000	USD
CY2020	us-gaap	Lease Cost LeaseCost	10605000	USD
CY2019	us-gaap	Lease Cost LeaseCost	11214000	USD
CY2019	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	200000	USD
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	27321000	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due After Year Five LesseeLeaseLiabilityPaymentsDueAfterYearFive	11942000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	39635000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	0	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	6932000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	7015000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	179000	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due Next Twelve Months LesseeLeaseLiabilityPaymentsDueNextTwelveMonths	7194000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	6187000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	179000	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due Year Two LesseeLeaseLiabilityPaymentsDueYearTwo	6366000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	5297000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	43000	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due Year Three LesseeLeaseLiabilityPaymentsDueYearThree	5340000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	4766000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	0	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due Year Four LesseeLeaseLiabilityPaymentsDueYearFour	4766000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	4428000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	0	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due Year Five LesseeLeaseLiabilityPaymentsDueYearFive	4428000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	11942000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	401000	USD
CY2020Q4	cohu	Lessee Lease Liability Payments Due LesseeLeaseLiabilityPaymentsDue	40036000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	8783000	USD
CY2020Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	-0	USD
CY2020Q4	cohu	Lessee Lease Liability Undiscounted Excess Amount LesseeLeaseLiabilityUndiscountedExcessAmount	8783000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	401000	USD
CY2020Q4	cohu	Lease Liability LeaseLiability	31253000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	100000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	8079000	USD
CY2020	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	57000	USD
CY2019	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	117000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	146000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	34000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	489000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	0	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	2403000	USD
CY2019	us-gaap	Product Warranty Accrual Additions From Business Acquisition ProductWarrantyAccrualAdditionsFromBusinessAcquisition	0	USD
CY2018	us-gaap	Product Warranty Accrual Additions From Business Acquisition ProductWarrantyAccrualAdditionsFromBusinessAcquisition	4369000	USD
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent	-2599000	USD
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent	216000	USD
CY2017Q4	us-gaap	Product Warranty Accrual ProductWarrantyAccrual	4849000	USD
CY2020	us-gaap	Product Warranty Accrual Warranties Issued ProductWarrantyAccrualWarrantiesIssued	6173000	USD
CY2019	us-gaap	Product Warranty Accrual Warranties Issued ProductWarrantyAccrualWarrantiesIssued	6714000	USD
CY2018	us-gaap	Product Warranty Accrual Warranties Issued ProductWarrantyAccrualWarrantiesIssued	7154000	USD
CY2020	us-gaap	Product Warranty Accrual Payments ProductWarrantyAccrualPayments	5946000	USD
CY2019	us-gaap	Product Warranty Accrual Payments ProductWarrantyAccrualPayments	8573000	USD
CY2018	us-gaap	Product Warranty Accrual Payments ProductWarrantyAccrualPayments	8358000	USD
CY2020	us-gaap	Product Warranty Accrual Additions From Business Acquisition ProductWarrantyAccrualAdditionsFromBusinessAcquisition	0	USD
CY2020	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	<table border="0" cellpadding="0" cellspacing="0" style="width: 100%; text-indent: 0px;"> <tbody> <tr style="vertical-align: top;"> <td style="width: 18pt;"> <p style="margin: 0pt; text-align: left; font-family: "Times New Roman", Times, serif; font-size: 10pt;"><b><em style="font: inherit;">12.</em> </b></p> </td> <td> <p style="margin: 0pt; text-align: left; font-family: "Times New Roman", Times, serif; font-size: 10pt;"><b>Commitments and Contingencies</b></p> </td> </tr> </tbody> </table> <p style="font-family: 'Times New Roman', Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;"> </p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt 0pt 0pt 18pt; text-align: left;">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 <em style="font: inherit;">no</em> assurance, we do <em style="font: inherit;">not</em> believe at the present time that the resolution of these matters will have a material adverse effect on our assets, financial position or results of operations.</p>
CY2019Q4	us-gaap	Product Warranty Accrual ProductWarrantyAccrual	6155000	USD
CY2018Q4	us-gaap	Product Warranty Accrual ProductWarrantyAccrual	8014000	USD
CY2020Q4	us-gaap	Product Warranty Accrual ProductWarrantyAccrual	6382000	USD
CY2019Q4	us-gaap	Product Warranty Accrual ProductWarrantyAccrual	6155000	USD
CY2018Q4	us-gaap	Product Warranty Accrual ProductWarrantyAccrual	8014000	USD
CY2020	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	4000	USD
CY2019	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	89000	USD
CY2018	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	38000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	42000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-697000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	432000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	6136000	USD
CY2018	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	1593000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	11000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	478000	USD
CY2018	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	157000	USD
CY2020	cohu	Disposal Group Including Discontinued Operation Impairment DisposalGroupIncludingDiscontinuedOperationImpairment	-0	USD
CY2019	cohu	Disposal Group Including Discontinued Operation Impairment DisposalGroupIncludingDiscontinuedOperationImpairment	1086000	USD
CY2018	cohu	Disposal Group Including Discontinued Operation Impairment DisposalGroupIncludingDiscontinuedOperationImpairment	-0	USD
CY2020	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	35000	USD
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	46000	USD
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	-608000	USD
CY2018	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	157000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	119000	USD
CY2018	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent	-8905000	USD
CY2018	us-gaap	Other Comprehensive Income Foreign Currency Translation Adjustment Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent	0	USD
CY2018	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-8905000	USD
CY2018	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent	-865000	USD
CY2018	us-gaap	Other Comprehensive Income Defined Benefit Plans Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent	60000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-805000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	7000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	7000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-8033000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-60000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8093000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent	-7522000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Translation Adjustment Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent	0	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-7522000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent	856000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent	-228000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	628000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-8378000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	228000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8150000	USD
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent	27321000	USD
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Translation Adjustment Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTranslationAdjustmentTaxPortionAttributableToParent	0	USD
CY2020Q1	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	138921000	USD
CY2020Q2	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	144084000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	150647000	USD
CY2020Q4	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	202355000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	636007000	USD
CY2019Q1	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	147809000	USD
CY2019Q2	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	150011000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-2383000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	29920000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-216000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	29704000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	-2877000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	-30198000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	1449000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	3832000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-4326000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-34030000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	143498000	USD
CY2019Q4	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	142011000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	583329000	USD
CY2020Q1	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	82837000	USD
CY2020Q2	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	83127000	USD
CY2020Q3	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	87147000	USD
CY2020Q4	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	111114000	USD
CY2020	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	364225000	USD
CY2019Q1	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	93394000	USD
CY2019Q2	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	87605000	USD
CY2019Q3	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	84565000	USD
CY2019Q4	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	87936000	USD
CY2019	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	353500000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-17318000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-4740000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-6646000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	14861000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.11
CY2020	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-13843000	USD
CY2019Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-22851000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-19383000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-10480000	USD
CY2019Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-16281000	USD
CY2019	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-68995000	USD
CY2020Q1	us-gaap	Profit Loss ProfitLoss	-17276000	USD
CY2020Q2	us-gaap	Profit Loss ProfitLoss	-4740000	USD
CY2020Q3	us-gaap	Profit Loss ProfitLoss	-6646000	USD
CY2020Q4	us-gaap	Profit Loss ProfitLoss	14861000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	-13801000	USD
CY2019Q1	us-gaap	Profit Loss ProfitLoss	-22687000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	-19359000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	-10326000	USD
CY2019Q4	us-gaap	Profit Loss ProfitLoss	-17320000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	-69692000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	-17276000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	-4740000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	-6646000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	14861000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-13801000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	-22643000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	-19323000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	-10468000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	-17266000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	-69700000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.42
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.16
CY2020Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.35
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.33
CY2019Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.56
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.47
CY2019Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.25
CY2019Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.39
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-1.68
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.42
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.11
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.16
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.35
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.33
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.55
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.47
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.25
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.42
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-1.69
CY2020Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.42
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.11
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.16
CY2020Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.34
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.33
CY2019Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.56
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.47
CY2019Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.25
CY2019Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.39
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-1.68
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.42
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.11
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.16
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.34
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.33
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.55
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.47
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.25
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.42
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-1.69

Files In Submission

Name	View Source	Status
0001437749-21-004277-index-headers.html	Edgar Link	pending
R39.htm	Edgar Link	pending
0001437749-21-004277-index.html	Edgar Link	pending
0001437749-21-004277.txt	Edgar Link	pending
0001437749-21-004277-xbrl.zip	Edgar Link	pending
cohu-20201226.xsd	Edgar Link	pending
cohu-20201226_cal.xml	Edgar Link	unprocessable
cohu-20201226_def.xml	Edgar Link	unprocessable
cohu-20201226_lab.xml	Edgar Link	unprocessable
cohu-20201226_pre.xml	Edgar Link	unprocessable
cohu20201226_10k.htm	Edgar Link	pending
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cohu20201226_10k_htm.xml	Edgar Link	completed
ex_227928.htm	Edgar Link	pending
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$COHU
COHU INC Stock $cohu

2020 Q4 Form 10-K Financial Statement

#000143774921004277 Filed on February 26, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$COHU COHU INC Stock $cohu

2020 Q4 Form 10-K Financial Statement

#000143774921004277 Filed on February 26, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$COHU
COHU INC Stock $cohu