Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 29, 2018 USD ($)	Dec. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Cash flows from operating activities:
Net income (loss) attributable to Cohu	$ (32,181)	$ 32,843	$ 3,039
Net loss from noncontrolling interest	(243)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Loss on disposal of microwave equipment segment		278	221
Total depreciation and amortization for reportable segments	26,047	9,195	10,412
Share-based compensation expense including restructuring charges	18,279	7,007	7,143
Amortization of inventory step-up and inventory related charges	24,179	1,404
Accrued retiree benefits	(560)	322	672
Deferred income taxes	(8,207)	(3,791)	(1,065)
Adjustment to contingent consideration liability	657	1,423
Changes in other assets	(2,961)	1,501	415
(Gain) loss on disposal and impairment of fixed assets	293	(42)	31
Changes in other accrued liabilities	198	979	162
Changes in current assets and liabilities, excluding effects from acquisitions and divestitures:
Accounts receivable	5,785	(3,259)	(4,617)
Inventories	2,043	(12,196)	4,608
Accrued compensation, warranty and other liabilities	3,985	937	(1,544)
Accounts payable	(7,103)	4,157	5,678
Deferred profit	37	(442)	3,309
Other current assets	148	952	(1,959)
Income taxes payable	4,041	(1,518)	(1,957)
Net cash provided by operating activities	34,437	39,750	24,548
Cash flows from investing activities, excluding effects from acquisitions and divestitures:
Net cash received from sale of land, facility and assets	1,005	104	874
Purchases of property, plant and equipment	(4,967)	(6,093)	(3,452)
Purchases of short-term investments	(38,700)	(37,010)	(50,568)
Sales and maturities of short-term investments	59,469	47,671	20,230
Net cash used in investing activities	(322,308)	(7,044)	(32,916)
Cash flows from financing activities:
Proceeds from Term Loan B	348,250
Payment of debt issuance costs	(7,072)
Cash dividends paid	(6,949)	(6,577)	(6,351)
Repayments of long-term debt	(2,323)	(1,631)
Issuance (repurchases) of common stock, net including restricted stock units vested and settled with cash to satisfy tax liabilities	(8,978)	10,353	(356)
Payment of contingent consideration	(823)
Net cash provided by (used in) financing activities	322,105	2,145	(6,707)
Effect of exchange rate changes on cash and cash equivalents	(3,599)	3,390	(4,250)
Net increase (decrease) in cash and cash equivalents	30,635	38,241	(19,325)
Cash and cash equivalents at beginning of year	134,286	96,045	115,370
Cash and cash equivalents at end of year including cash from discontinued operations	164,921	134,286	96,045
Cash held by discontinued operations (Note 12)	(461)
Supplemental disclosure of cash flow information:
Cash paid during the year for income taxes	6,243	7,094	6,808
Cash paid for interest	4,977
Dividends declared but not yet paid	2,445	1,705	1,606
Property, plant and equipment purchases included in accounts payable	599	260	445
Inventory capitalized as capital assets	857	190	201
Capitalized cloud computing costs included in accounts payable	829
Xcerra [Member]
Cash flows from investing activities, excluding effects from acquisitions and divestitures:
Payment for purchase of business, net of cash received	(339,115)
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member]
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Adjustment to contingent consideration liability	657	1,423
Cash flows from investing activities, excluding effects from acquisitions and divestitures:
Payment for purchase of business, net of cash received		$ (11,716)