0001039399-20-000089 | 10-Q | XBRL Viewer

Print Document View Excel Document

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 26, 2020	Oct. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 26, 2020
Document Transition Report	false
Entity File Number	000-50307
Entity Registrant Name	FormFactor, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3711155
Entity Address, Address Line One	7005 Southfront Road
Entity Address, City or Town	Livermore
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94551
City Area Code	925
Local Phone Number	290-4000
Title of 12(b) Security	Common stock, $0.001 par value
Trading Symbol	FORM
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		77,387,997
Amendment Flag	false
Entity Central Index Key	0001039399
Current Fiscal Year End Date	--12-26
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3

Condensed Consolidated Balance Sheets $ in Thousands	3 Months Ended	9 Months Ended
Condensed Consolidated Balance Sheets $ in Thousands	Sep. 26, 2020 USD ($) $ / shares	Sep. 26, 2020 USD ($) $ / shares	Dec. 28, 2019 USD ($) $ / shares
Current assets:
Cash and cash equivalents	$ 185,368	$ 185,368	$ 144,545
Marketable securities	56,100	56,100	76,327
Accounts receivable, net	96,946	96,946	97,868
Inventories, net	94,616	94,616	83,258
Restricted cash	1,477	1,477	1,981
Prepaid expenses and other current assets	21,687	21,687	15,064
Total current assets	456,194	456,194	419,043
Restricted cash	1,398	1,398	1,411
Operating Lease, Right-of-Use Asset	29,320	29,320	31,420
Property, plant and equipment, net of accumulated depreciation	97,528	97,528	58,747
Goodwill	220,757	220,757	199,196
Intangibles, net	37,937	37,937	57,610
Deferred tax assets	71,464	71,464	71,252
Other assets	1,009	1,009	1,203
Total assets	915,607	915,607	839,882
Current liabilities:
Accounts payable	62,903	62,903	40,914
Accrued liabilities	44,026	44,026	36,439
Current portion of term loans, net of unamortized issuance costs	9,120	9,120	42,846
Deferred revenue	13,670	13,670	9,810
Operating Lease, Liability, Current	6,555	6,555	6,551
Total current liabilities	136,274	136,274	136,560
Term loans, less current portion, net of unamortized issuance costs	26,874	26,874	15,639
Deferred tax liabilities	5,682	5,682	6,986
Long-term operating lease liabilities	26,794	26,794	29,088
Other liabilities	5,841	5,841	10,612
Total liabilities	201,465	201,465	198,885
Stockholders’ equity:
Common stock, $0.001 par value	78	78	76
Additional paid-in capital	896,576	896,576	885,821
Accumulated other comprehensive income (loss)	2,479	2,479	(659)
Accumulated deficit	(184,991)	(184,991)	(244,241)
Total stockholders’ equity	714,142	714,142	640,997
Total liabilities and stockholders’ equity	915,607	915,607	839,882
Marketable securities	56,100	56,100	76,327
Gross profit	76,749	210,306
Accounts Receivable, Allowance for Credit Loss, Current	$ 222	$ 222	$ 222
Common stock, par value (In dollars per share) \| $ / shares	$ 0.001	$ 0.001	$ 0.001
Corporate and Other
Gross profit	$ (6,457)	$ (19,219)

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Statement of Financial Position [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 222	$ 222
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 287,141	$ 273,001
Common stock, par value (In dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (In shares)	250,000,000	250,000,000
Common stock, shares issued (In shares)	77,383,494	75,764,990
Common stock, shares outstanding (In shares)	77,383,494	75,764,990

Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Income Statement [Abstract]
Revenues	$ 177,996	$ 140,604	$ 496,573	$ 410,835
Cost of revenues	101,247	85,286	286,267	247,644
Gross profit	76,749	55,318	210,306	163,191
Operating expenses:
Research and development	22,878	20,096	65,064	59,893
Selling, general and administrative	31,834	25,887	82,282	77,354
Total operating expenses	54,712	45,983	147,346	137,247
Operating income	22,037	9,335	62,960	25,944
Interest income	249	724	1,310	1,988
Interest expense	(193)	(422)	(682)	(1,539)
Other income, net	299	226	141	223
Income before income taxes	22,392	9,863	63,729	26,616
Provision (benefit) for income taxes	(499)	1,584	4,479	5,906
Net income	$ 22,891	$ 8,279	$ 59,250	$ 20,710
Net income per share:
Basic (In dollars per share)	$ 0.30	$ 0.11	$ 0.78	$ 0.28
Diluted (In dollars per share)	$ 0.29	$ 0.11	$ 0.75	$ 0.27
Basic
Basic (In shares)	77,029	75,280	76,436	74,749
Diluted (In shares)	78,809	77,291	78,534	76,763

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 22,891	$ 8,279	$ 59,250	$ 20,710
Other comprehensive income (loss), net of tax:
Translation adjustments and other	1,867	(1,814)	2,231	(2,042)
Unrealized gains (losses) on available-for-sale marketable securities	(148)	11	349	304
Unrealized gains (losses) on derivative instruments	302	(536)	558	(1,222)
Other comprehensive income (loss), net of tax	2,021	(2,339)	3,138	(2,960)
Comprehensive income	$ 24,912	$ 5,940	$ 62,388	$ 17,750

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669619-108580

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8924-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721683-107760

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22595-107794

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669625-108580

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22663-107794

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121326447&loc=SL5780133-109256

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22658-107794

+ Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

+ References

+ Details

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (In shares) at Dec. 29, 2018		74,139,712,000
Beginning balance at Dec. 29, 2018	$ 580,164	$ 74	$ 862,897	$ 780	$ (283,587)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under the Employee Stock Purchase Plan (In shares)		544,271,000
Issuance of common stock under the Employee Stock Purchase Plan	6,806		6,806
Issuance of common stock pursuant to exercise of options for cash (In shares)		112,956,000
Issuance of common stock pursuant to exercise of options	754		754
Issuance of common stock pursuant to vesting of restricted stock units (In shares)		899,295,000
Issuance of common stock pursuant to exercise of options	(7,896)	$ 2	(7,898)
Stock-based compensation	16,968		16,968
Other comprehensive loss	(2,960)			(2,960)
Net income	20,710				20,710
Ending balance (In shares) at Sep. 28, 2019		75,696,234,000
Ending balance at Sep. 28, 2019	614,546	$ 76	879,527	(2,180)	(262,877)
Beginning balance (In shares) at Jun. 29, 2019		74,691,781,000
Beginning balance at Jun. 29, 2019	604,102	$ 75	875,024	159	(271,156)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under the Employee Stock Purchase Plan (In shares)		242,774,000
Issuance of common stock under the Employee Stock Purchase Plan	3,136	$ 0	3,136
Issuance of common stock pursuant to exercise of options for cash (In shares)		93,749,000
Issuance of common stock pursuant to exercise of options	664		664
Issuance of common stock pursuant to vesting of restricted stock units (In shares)		667,930,000
Issuance of common stock pursuant to exercise of options	(5,740)		(5,741)
Stock-based compensation	6,444		6,444
Other comprehensive loss	(2,339)			(2,339)
Net income	8,279				8,279
Ending balance (In shares) at Sep. 28, 2019		75,696,234,000
Ending balance at Sep. 28, 2019	$ 614,546	$ 76	879,527	(2,180)	(262,877)
Beginning balance (In shares) at Dec. 28, 2019	75,764,990	75,764,990,000
Beginning balance at Dec. 28, 2019	$ 640,997	$ 76	885,821	(659)	(244,241)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under the Employee Stock Purchase Plan (In shares)		485,566,000
Issuance of common stock under the Employee Stock Purchase Plan	7,875		7,875
Issuance of common stock pursuant to exercise of options for cash (In shares)		205,769,000
Issuance of common stock pursuant to exercise of options	1,713	$ 1	1,712
Issuance of common stock pursuant to vesting of restricted stock units (In shares)		927,169,000
Issuance of common stock pursuant to exercise of options	(15,382)	$ 1	(15,383)
Stock-based compensation	16,551		16,551
Other comprehensive loss	3,138			3,138
Net income	$ 59,250				59,250
Ending balance (In shares) at Sep. 26, 2020	77,383,494	77,383,494,000
Ending balance at Sep. 26, 2020	$ 714,142	$ 78	896,576	2,479	(184,991)
Beginning balance (In shares) at Jun. 27, 2020		76,501,459,000
Beginning balance at Jun. 27, 2020	690,722	$ 77	898,069	458	(207,882)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under the Employee Stock Purchase Plan (In shares)		173,975,000
Issuance of common stock under the Employee Stock Purchase Plan	3,809		3,809
Issuance of common stock pursuant to exercise of options for cash (In shares)		608,060,000
Issuance of common stock pursuant to exercise of options	(11,582)		(11,583)
Issuance of common stock pursuant to vesting of restricted stock units (In shares)		100,000,000
Issuance of common stock pursuant to exercise of options	844	$ 1	844
Stock-based compensation	5,437		5,437
Other comprehensive loss	2,021			2,021
Net income	$ 22,891				22,891
Ending balance (In shares) at Sep. 26, 2020	77,383,494	77,383,494,000
Ending balance at Sep. 26, 2020	$ 714,142	$ 78	$ 896,576	$ 2,479	$ (184,991)

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash flows from operating activities:
Net income	$ 59,250	$ 20,710
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	14,491	12,644
Amortization	20,249	20,248
Reduction in the carrying amount of right-of-use assets	4,294	3,921
Stock-based compensation expense	16,774	17,088
Provision for excess and obsolete inventories	9,763	8,046
Gain on contingent consideration	(3,771)	0
Other adjustments to reconcile net income to net cash provided by operating activities	(977)	152
Changes in assets and liabilities:
Accounts receivable	5,712	10,580
Inventories	(18,566)	(17,246)
Prepaid expenses and other current assets	5,619	3,727
Other assets	219	(595)
Accounts payable	18,054	10,074
Accrued liabilities	4,754	(856)
Other liabilities	272	2,374
Deferred revenues	3,806	3,625
Operating lease liabilities	(4,496)	(3,660)
Net cash provided by operating activities	124,209	83,378
Cash flows from investing activities:
Acquisition of property, plant and equipment	(41,887)	(14,242)
Acquisition of business, net of cash acquired	(34,999)	0
Proceeds from sale of a subsidiary	82	93
Purchases of marketable securities	50,330	33,704
Net cash used in investing activities	(56,195)	(40,047)
Net cash used in investing activities
Payments to Acquire Marketable Securities	29,721	59,602
Cash flows from financing activities:
Proceeds from issuances of common stock	9,588	7,672
Tax withholdings related to net share settlements of equity awards	(15,382)	(7,898)
Proceeds from term loan debt	18,000	0
Principal repayments on term loans	(41,098)	(18,750)
Payment of term loan debt issuance costs	(78)	0
Net cash used in financing activities	(28,970)	(18,976)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	1,262	(161)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	40,306	24,194
Net increase in cash, cash equivalents and restricted cash	147,937	100,546
Cash, cash equivalents and restricted cash, beginning of period	188,243	124,740
Fair value of stock options and restricted stock-based awards assumed in connection with acquisition of Cascade Microtech
Change in accounts payable and accrued liabilities related to property, plant and equipment purchases	3,041	1,062
Operating lease, right-of-use assets obtained in exchange for lease obligations	1,549	36,300
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net	7,475	2,875
Cash paid for interest	$ 683	$ 1,128

Basis of Presentation and New Accounting Pronouncements	9 Months Ended
Basis of Presentation and New Accounting Pronouncements	Sep. 26, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and New Accounting Pronouncements	Basis of Presentation and New Accounting Pronouncements Basis of Presentation The accompanying condensed consolidated financial information of FormFactor, Inc. is unaudited and has been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). However, such information reflects all adjustments, consisting only of normal recurring adjustments, which are, in the opinion of management, necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods. The financial information as of December 28, 2019 is derived from our 2019 Annual Report on Form 10-K. The condensed consolidated financial statements included herein should be read in conjunction with the consolidated financial statements and the notes thereto included in our 2019 Annual Report on Form 10-K filed with the SEC on February 21, 2020. The results of operations for the interim periods presented are not necessarily indicative of the results to be expected for the full year. Fiscal Year We operate on a 52/53 week fiscal year, whereby the fiscal year ends on the last Saturday of December. Fiscal 2020 and 2019 each contain 52 weeks and the nine months ended September 26, 2020 and September 28, 2019 each contained 39 weeks. Fiscal 2020 will end on December 26, 2020. Significant Accounting Policies Our significant accounting policies have not changed during the nine months ended September 26, 2020 from those disclosed in our Annual Report on Form 10-K for the year ended December 28, 2019. Reclassifications Certain immaterial reclassifications were made to the prior year financial statements to conform to the current year presentation. New Accounting Pronouncements ASU 2016-13 In June 2016, the Financial Accounting Standard Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-13, "Measurement of Credit Losses on Financial Instruments (Topic 326)." The provisions of this standard require financial assets measured at amortized cost to be presented at the net amount expected to be collected. An allowance account would be established to present the net carrying value at the amount expected to be collected. ASU 2016-13 also provides that credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. The guidance was amended through various ASU's subsequent to ASU 2016-13, all of which was effective beginning fiscal 2020. We adopted ASU 2016-13 on a prospective basis on December 29, 2019, the first day of fiscal 2020. The adoption did not have a material effect on our financial position, results of operations or cash flows. ASU 2018-15 In August 2018, the FASB issued ASU 2018-15, "Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." The new guidance clarifies the accounting for implementation costs in cloud computing arrangements. ASU 2018-15 is effective for fiscal years, including interim periods within those fiscal years, beginning after December 15, 2019. We adopted ASU 2018-15 on a prospective basis on December 29, 2019, the first day of fiscal 2020. The adoption did not have a material effect on our financial position, results of operations or cash flows. ASU 2019-12 In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740),” which simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption of the amendments is permitted, including adoption in any interim period for which financial statements have not yet been issued. Depending on the amendment, adoption may be applied on the retrospective, modified retrospective or prospective basis. We have not yet determined the impact of this standard on our financial position, results of operations or cash flows. ASU 2020-04 In March 2020, the FASB issued ASU 2020-04, "Referenced Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting." The amendments in this update apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. The amendments in this update are elective and are effective upon issuance for all entities. We have not yet evaluated the transition approach for our LIBOR indexed contracts and have not determined whether we will be electing such expedients and exceptions. Release No. 33-10786 In May 2020, the SEC issued Final Rule Release No. 33-10786, which amends the financial statement requirements for acquisitions and dispositions of businesses and related pro forma financial information required under SEC Regulation S-X, Rule 3-05. The final rule modifies the significance test required in SEC Regulation S-X, Rule 1-02(w) by raising the significance threshold for reporting dispositions of a business from 10% to 20% and by modifying the calculation of the investment and income tests. The modifications are effective for fiscal years starting after December 31, 2020 with early adoption permitted. We early adopted these modifications on June 28, 2020, the first day of the third quarter.

Concentration of Credit and Other Risks

9 Months Ended

Sep. 26, 2020

Risks and Uncertainties [Abstract]

Concentration of Credit and Other Risks

Each of the following customers accounted for 10% or more of our revenues for the periods indicated:


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Intel Corporation	25.6	%	23.9	%	32.4	%	23.8	%
Taiwan Semiconductor Manufacturing Co.,LTD.	10.6	%	*		*		*
Samsung Electronics., LTD.	10.6	%	*		*		10.0	%
Micron Technology, Inc.	10.1	%	11.9	%	*		*
SK Hynix Inc.	*		13.5	%	*		10.6	%
	56.9	%	49.3	%	32.4	%	44.4	%

*Represents less than 10% of total revenues.

At September 26, 2020, two customers accounted for 26.6% and 18.3% of gross accounts receivable, respectively. At December 28, 2019, three customers accounted for 25.7%, 15.1% and 11.5% of gross accounts receivable, respectively.

Inventories

9 Months Ended

Sep. 26, 2020

Inventory Disclosure [Abstract]

Inventories

Inventories, net

Inventories are stated at the lower of cost (principally standard cost, which approximates actual cost on a first in, first out basis) or net realizable value.

Inventories, net, consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Raw materials	$	44,586	$	38,528
Work-in-progress	32,770		29,720
Finished goods	17,260		15,010
	$	94,616	$	83,258

Acquisition

9 Months Ended

Sep. 26, 2020

Business Combinations [Abstract]

Acquisition

FRT Acquisition

On October 9, 2019, we acquired 100% of the shares of FRT GmbH ("FRT"), a German-based company, for total consideration of $26.9 million, net of cash acquired of $1.7 million. The fair value of the purchase consideration was comprised of a $22.2 million cash payment and $6.5 million of contingent consideration as of October 9, 2019.

We estimated the acquisition price and the allocation of fair value to assets acquired and liabilities assumed as of the acquisition date, October 9, 2019. We subsequently made certain immaterial adjustments to the acquisition price allocation related to

acquired assets and assumed liabilities, including to intangibles assets. We finalized our allocation of the assets acquired, including goodwill and intangibles, and liabilities assumed for the purchase as follows (in thousands):


	Amount
Cash and cash equivalents	$	1,687
Accounts receivable	3,079
Inventory	2,643
Property, plant and equipment	696
Operating lease, right of use assets	335
Prepaid expenses and other current assets	838
Tangible assets acquired	9,278
Customer deposits	(1,933)
Accounts payable and accrued liabilities	(1,182)
Operating lease liabilities	(335)
Deferred tax liabilities	(5,757)
Total tangible assets acquired and liabilities assumed	71
Intangible assets	17,429
Goodwill	11,123
Net Assets Acquired	$	28,623

The intangible assets as of the closing date of the acquisition included (in thousands):


	Amount		Weighted Average Useful Life (in years)
Developed technologies	$	12,505	8.0
Customer relationships	3,071		6.0
Backlog	1,645		0.5
Trade names	208		2.0
Total intangible assets	$	17,429	7.0

Indications of fair value of the intangible assets acquired in connection with the acquisition were determined using either the income, market or replacement cost methodologies. The intangible assets are being amortized over periods which reflect the pattern in which economic benefits of the assets are expected to be realized.

The contingent consideration is a cash amount equal to 1.5x Earnings Before Interest and Tax ("EBIT") as defined in the purchase agreement, from a minimum of zero up to a maximum of €10.3 million, payable subject to the performance of the acquired business in calendar 2020. For purchase accounting, we estimated the fair value of contingent consideration using a probability weighted approach. Key assumptions in determining the fair value of contingent consideration include estimating the probability of achieving certain EBIT levels and discounting at an appropriate discount rate. See Note 8, Fair Value and Derivative Instruments, for further discussion on the fair value of contingent consideration.

This acquisition strengthens our leadership in test and measurement by expanding our addressable market into 3D hybrid surface metrology and extending the optical applications scope of our existing Systems segment.

Separate from the purchase agreement, on October 25, 2019, we entered into a term loan agreement with a lender for an aggregate amount of $23.4 million to finance the acquisition. See Note 6, Debt, for further discussion of the term loan agreement.

Identifiable Intangible Assets

Valuation of intangible assets involves multiple assumptions. The key assumptions are described below.

Developed technologies acquired primarily consists of existing technology related to hybrid 3D surface metrology measurement equipment. We valued the developed technologies using the multi-period excess earnings method under the income approach. Using this approach, the estimated fair values were calculated using expected future cash flows from specific products discounted to their net present values at an appropriate risk-adjusted rate of return.

Customer relationships represent the fair value of future projected revenues that will be derived from the sale of products to FRT's existing customers. We valued customer relationships using the incremental cash flow method. This method estimates value based on the incremental cash flow afforded by having the customers relationships in place on the acquisition date versus having no relationships in place and needing to replicate or replace those relationships. The incremental cash flows are then discounted to a present value to arrive at an estimate of fair value for this asset class.

Backlog represents business under existing contractual obligations. Expected cash flow from backlog was valued on a direct cash flow basis.

The identified trade names intangible relates to the estimated fair value of future cash flows related to the FRT brand. We valued trade names by applying the relief-from-royalty method under the income approach. This method is based on the application of a royalty rate to forecasted revenue under the trade name.

Goodwill

The excess of purchase price over the fair value assigned to the assets acquired and liabilities assumed represents the amount of goodwill resulting from the acquisition. We believe the factors that contributed to goodwill include synergies that are specific to our consolidated business, such as cost savings and operational efficiencies, and the acquisition of a talented workforce that expands our expertise in business development and commercializing semiconductor test products, none of which qualify for recognition as a separate intangible asset. We do not expect any portion of this goodwill to be deductible for tax purposes. The goodwill attributable to the acquisition was recorded as a non-current asset and is not amortized, but is subject to an annual review for impairment.

The goodwill arising from the acquisition was allocated to the FRT reporting unit within the Systems reportable segment.

We have not presented unaudited combined pro forma financial information as the FRT acquisition was not significant to our consolidated results of operations and financial position.

Baldwin Park Acquisition

On July 30, 2020, we acquired the probe card assets of Advantest Corporation ("Baldwin Park") for total cash consideration of $35 million. This acquisition brings important enabling technologies and capabilities for designing and manufacturing advanced probe cards, and adds a complementary 3D-NAND Flash probe-card product that is qualified and in production at one of the world's leading NAND Flash manufacturers.

As of the reporting date, we have not completed the valuation of assets acquired and liabilities assumed. While the identification of identifiable intangible assets is still in process, we expect certain amounts provisionally recorded as goodwill will be ultimately allocated to such assets as customer relationships, developed technologies, backlog and potentially other technology-related assets as we complete purchase accounting. Consistent with the status of the identification of intangible assets, at this time we do not have an estimate of the allocation of value between amortizing and non-amortizing intangible assets, however we do expect that some amount of intangible assets provisionally recorded as goodwill will ultimately be allocated to an amortizing intangible asset. At the time such amount is estimable, we will record any amortization required between the acquisition date and the date at which the amounts become estimable. While we do not yet have a reasonable basis on which to record any such amortization, the impact to the financial statements as a whole is not expected to be material assuming typical lives of these assets and ranges of potential allocation of value.

The amounts presented below represent provisional amounts of assets acquired and liabilities assumed, which are recorded based on the best information available. As described above, adjustments to fair value for intangible assets have not yet been determined, however preliminary estimates have been determined for trade inventories and property, plant, and equipment step up. These provisional amounts are included in the table below and in the condensed consolidated balance sheets and are subject to revision as the fair value of the associated assets acquired and liabilities assumed is finalized. The total estimated purchase price would be allocated to the underlying assets acquired and liabilities assumed based on the provisional amounts, as follows (in thousands):


	Amount
Accounts receivable	$	4,365
Inventory	2,318
Property, plant and equipment	9,053
Operating lease, right of use assets	519
Prepaid expenses and other current assets	317
Tangible assets acquired	16,572

Accounts payable and accrued liabilities	(572)
Operating lease liabilities	(519)

Total tangible assets acquired and liabilities assumed	15,481

Goodwill	19,519
Net Assets Acquired	$	35,000

The operating results of the acquired business are included in the Company’s results of operations since the date of acquisition. Pro forma financial information has not been provided for the acquisition of Baldwin Park as it is not significant to the Company’s operations and financial position. Included in Cost of revenues in the Condensed Consolidated Statements of Income in the three and nine months ended September 26, 2020 is $0.5 million of amortization of the estimated step-up to fair value for finished goods and work-in-process inventories acquired and then sold to customers within the quarter.

Goodwill and Intangible Assets

9 Months Ended

Sep. 26, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

Goodwill by reportable segment was as follows (in thousands):


	Probe Cards		Systems		Total
Goodwill, gross, as of December 29, 2018	$	172,482	$	16,732	$	189,214
Addition - FRT GmbH Acquisition	—		10,148		10,148
Foreign currency translation	—		(166)		(166)
Goodwill, gross, as of December 28, 2019	172,482		26,714		199,196
Addition - FRT GmbH Acquisition	—		975		975
Addition - Baldwin Park Acquisition	19,519		—		19,519
Foreign currency translation	—		1,067		1,067
Goodwill, gross, as of September 26, 2020	$	192,001	$	28,756	$	220,757

No goodwill impairments have been recorded during the nine months ended September 26, 2020 and the twelve months ended December 28, 2019.

Intangible assets were as follows (in thousands):


	September 26, 2020						December 28, 2019
Intangible Assets	Gross		Accumulated Amortization		Net		Gross		Accumulated Amortization		Net
Developed technologies	$	156,659	$	131,289	$	25,370	$	154,951	$	116,138	$	38,813
Trade names	7,870		7,231		639		7,816		6,976		840
Customer relationships	43,460		31,532		11,928		44,229		27,057		17,172
Backlog	1,744		1,744		—		1,676		891		785
	$	209,733	$	171,796	$	37,937	$	208,672	$	151,062	$	57,610

Amortization expense was included in our Condensed Consolidated Statements of Income as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Cost of revenues	$	4,985	$	4,707	$	15,661	$	14,137
Selling, general and administrative	1,547		1,372		4,588		6,111
	$	6,532	$	6,079	$	20,249	$	20,248

The estimated future amortization of intangible assets is as follows (in thousands):


Fiscal Year	Amount
Remainder of 2020	$	6,105
2021	14,945
2022	5,708
2023	3,954
2024	2,200
Thereafter	5,025
	$	37,937

Debt

9 Months Ended

Sep. 26, 2020

Debt Disclosure [Abstract]

Debt

Our debt consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Term loans	$	36,070	$	58,514
Less unamortized issuance costs	(76)		(29)
Term loans less issuance costs	$	35,994	$	58,485

Future principal and interest payments on our term loans as of September 26, 2020, based on the interest rate in effect at that date were as follows (in thousands):


	Payments Due In Fiscal Year
	Remainder 2020		2021		2022		2023		2024		Thereafter		Total
Term loans - principal payments	$	2,278	$	9,133	$	9,161	$	1,050	$	1,080	$	13,368	$	36,070
Term loans - interest payments (1)	145		503		377		290		271		1,433		3,019
Total	$	2,423	$	9,636	$	9,538	$	1,340	$	1,351	$	14,801	$	39,089

(1) Represents our minimum interest payment commitments at 1.91% per annum for the Building Term Loan and 1.30% per annum for the FRT Term Loan.

CMI Term Loan

On June 24, 2016, we entered into a Credit Agreement (the “Credit Agreement”) with HSBC Bank USA, National Association ("HSBC"), as administrative agent, co-lead arranger, sole bookrunner and syndication agent, other lenders that may from time-to-time be a party to the Credit Agreement, and certain guarantors. Pursuant to the Credit Agreement, we obtained a senior secured term loan facility of $150 million (the “CMI Term Loan”). The proceeds of the CMI Term Loan were used to finance a portion of the purchase price paid in connection with the Cascade Microtech acquisition in fiscal 2016 and to pay related bank fees and expenses.

The CMI Term Loan bore interest at a rate equal to, at our option, (i) the applicable London Interbank Offered Rate ("LIBOR") rate plus 2.00% per annum or (ii) Base Rate (as defined in the Credit Agreement) plus 1.00% per annum. We elected to pay interest at 2.00% over the one-month LIBOR rate. Interest payments were payable in monthly installments over a five-year period.

The principal payments on the CMI Term Loan were paid in equal quarterly installments that began June 30, 2016, in an annual amount equal to 5% for year one, 10% for year two, 20% for year three, 30% for year four and 35% for year five. The final payment on the CMI Term Loan was June 30, 2020 and we are no longer subject to the terms of the Credit Agreement.

FRT Term Loan

On October 25, 2019, we entered into a $23.4 million three-year credit facility loan agreement (the "FRT Term Loan") with HSBC Trinkaus & Burkhardt AG, Germany, to fund the acquisition of FRT GmbH, which we acquired on October 9, 2019. See Note 4, Acquisition, for further details of the acquisition.

The FRT Term Loan bears interest at a rate equal to the Euro Interbank Offered Rate ("EURIBOR") plus 1.75% per annum and will be repaid in quarterly installments of approximately $2.0 million plus interest. The interest rate at September 26, 2020 was 1.30%

The obligations under the FRT Term Loan are fully and unconditionally guaranteed by FormFactor, Inc. The FRT Term Loan contains negative covenants customary for financing of this type, including covenants that place limitations on the incurrence of additional indebtedness, the creation of liens, the payment of dividends; dispositions; fundamental changes, including mergers and acquisitions; loans and investments; sale leasebacks; negative pledges; transactions with affiliates; changes in fiscal year; sanctions and anti-bribery laws and regulations, and modifications to charter documents in a manner materially adverse to the Lenders. The FRT Term Loan also contains affirmative covenants and representations and warranties customary for financing of this type. As of September 26, 2020, the balance outstanding pursuant to the FRT term loan was $18.3 million and we were in compliance with all covenants.

Building Term Loan

On June 22, 2020, we entered into an $18.0 million 15-year credit facility loan agreement (the “Building Term Loan”) with MUFG Union Bank, National Association ("Union Bank"). The proceeds of the Building Term Loan were used to purchase a building adjacent to our leased facilities in Livermore, California.

The Building Term Loan bears interest at a rate equal to the applicable LIBOR rate plus 1.75% per annum. Interest payments are payable in monthly installments over a fifteen-year period. The interest rate at September 26, 2020 was 1.91%.

On March 17, 2020, we entered into an interest rate swap agreement with Union Bank to hedge the interest payments on the Building Term Loan for the notional amount of $18.0 million. As future levels of LIBOR over the life of the loan are uncertain, we entered into this interest-rate swap agreement to hedge the exposure in interest rate risks associated with movement in LIBOR rates. By entering into the agreement, we convert a floating rate interest at one-month LIBOR plus 1.75% into a fixed rate interest at 2.75%. The interest rate swap also includes a 0% floor that is effective for one year from the date of the swap. As of September 26, 2020, the notional amount of the loan that is subject to this interest rate swap is $17.8 million. See Note 8, Fair Value and Derivative Instruments, for additional information.

The obligations under the Building Term Loan are guaranteed by a deed of trust covering certain real property and improvements and certain personal property used in connection therewith. The deed of trust creates a first priority lien or encumbrance on the property with only such exceptions as may be approved by the Union Bank in writing.

The Credit Agreement contains covenants customary for financing of this type. As of September 26, 2020, the balance outstanding pursuant to the Building Term Loan was $17.8 million and we were in compliance with all covenants under the Credit Agreement.

Accrued Liabilities

9 Months Ended

Sep. 26, 2020

Payables and Accruals [Abstract]

Accrued Liabilities

Accrued LiabilitiesAccrued liabilities consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Accrued compensation and benefits	$	28,273	$	21,329
Accrued income and other taxes	5,989		6,846
Accrued warranty	1,875		1,942
Accrued employee stock purchase plan contributions withheld	1,648		3,331
Accrued contingent consideration	2,966		—
Other accrued expenses	3,275		2,991
	$	44,026	$	36,439

Fair Value and Derivative Instruments

9 Months Ended

Sep. 26, 2020

Fair Value Disclosures [Abstract]

Fair Value and Derivative Instruments

Whenever possible, the fair values of our financial assets and liabilities are determined using quoted market prices of identical securities or quoted market prices of similar securities from active markets. The three levels of inputs that may be used to measure fair value are as follows:

•Level 1 valuations are obtained from real-time quotes for transactions in active exchange markets involving identical securities;

•Level 2 valuations utilize significant observable inputs, such as quoted prices for similar assets or liabilities, quoted prices near the reporting date in markets that are less active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and

•Level 3 valuations utilize unobservable inputs to the valuation methodology and include our own data about assumptions market participants would use in pricing the asset or liability based on the best information available under the circumstances.

We did not have any transfers of assets or liabilities measured at fair value on a recurring basis to or from Level 1, Level 2 or Level 3 during the three and nine months ended September 26, 2020 or the year ended December 28, 2019.

The carrying values of Cash, Accounts receivable, net, Restricted cash, Prepaid expenses and other current assets, Accounts payable, Accrued liabilities, and Current portion of term loans, net of unamortized issuance costs, approximate fair value due to their short maturities.

No changes were made to our valuation techniques during the first nine months of fiscal 2020.

Assets and Liabilities Measured at Fair Value on a Recurring Basis

Assets and liabilities measured at fair value on a recurring basis were as follows (in thousands):


September 26, 2020	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	71,663	$	—	$	—	$	71,663



Marketable securities:
U.S. treasuries	34,198		—		—		34,198
Certificates of deposit	—		2,428		—		2,428
U.S. agency securities	—		2,083		—		2,083
Corporate bonds	—		17,391		—		17,391

	34,198		21,902		—		56,100
Foreign exchange derivative contracts	—		470		—		470

Total assets	$	105,861	$	22,372	$	—	$	128,233
Liabilities:

Interest rate swap derivative contracts	$	—	$	(271)	$	—	$	(271)
Contingent consideration	—		—		(2,966)		(2,966)
Total liabilities	$	—	$	(271)	$	(2,966)	$	(3,237)


December 28, 2019	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	17,056	$	—	$	—	$	17,056


Marketable securities:
U.S. treasuries	10,468		—		—		10,468
Certificates of deposit	—		3,590		—		3,590
U.S. agency securities	—		24,430		—		24,430
Corporate bonds	—		33,928		—		33,928
Commercial paper	—		3,911		—		3,911
	10,468		65,859		—		76,327
Foreign exchange derivative contracts	—		41		—		41
Interest rate swap derivative contracts	—		26		—		26
Total assets	$	27,524	$	65,926	$	—	$	93,450
Liabilities:
Foreign exchange derivative contracts	$	—	$	(240)	$	—	$	(240)
Contingent consideration	—		—		(5,364)		(5,364)
Total liabilities	$	—	$	(240)	$	(5,364)	$	(5,604)

Cash Equivalents

The fair value of our cash equivalents is determined based on quoted market prices for similar or identical securities.

Marketable Securities

We classify our marketable securities as available-for-sale and value them utilizing a market approach. Our investments are priced by pricing vendors who provide observable inputs for their pricing without applying significant judgment. Broker pricing is used mainly when a quoted price is not available, the investment is not priced by our pricing vendors or when a broker price is more reflective of fair value. Our broker-priced investments are categorized as Level 2 investments because fair value is based on similar assets without applying significant judgments. In addition, all investments have a sufficient trading volume to demonstrate that the fair value is appropriate.

Unrealized gains and losses were immaterial and were recorded as a component of Accumulated other comprehensive income in our Condensed Consolidated Balance Sheets. We did not have any other-than-temporary unrealized gains or losses at either period end included in these financial statements.

Contingent Consideration

Contingent consideration, arising from the acquisition of FRT, is a cash amount equal to 1.5x EBIT as defined in the purchase agreement, up to a maximum of €10.3 million, payable subject to the performance of the acquired business in calendar 2020. We estimated the fair value of contingent consideration using a probability weighted approach. Key assumptions in determining the fair value of contingent consideration include estimating EBIT levels that are likely to be achieved during the performance period and discounting at an appropriate discount rate. Contingent consideration as of September 26, 2020 was estimated to be $3.0 million, a net decrease of $2.4 million from $5.4 million as of December 28, 2019. The net decrease was as a result of a $1.2 million increase in the estimated contingent consideration upon acquisition and as part of purchase accounting that was adjusted in the first fiscal quarter of 2020, offset by a net $3.6 million decrease in the estimated contingent consideration from subsequent remeasurement of the liability and foreign currency translation.

Interest Rate Swaps

The fair value of our interest rate swap contracts is determined at the end of each reporting period based on valuation models that use interest rate yield curves as inputs. For accounting purposes, our interest rate swap contracts qualify for, and are designated as, cash flow hedges. The cash flows associated with the interest rate swaps are reported in Net cash provided by operating activities in our Condensed Consolidated Statements of Cash Flows and the fair value of the interest rate swap contracts are recorded within Accrued liabilities and Other liabilities in our Condensed Consolidated Balance Sheets.

The impact of the interest rate swaps on our Condensed Consolidated Statements of Income was as follows (in thousands):


	Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)		Location of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		Location of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)
Three Months Ended September 26, 2020	$	(53)	Interest expense	$	(38)	Interest expense	$	—
Three Months Ended September 28, 2019	$	12	Interest expense	$	113	Interest expense	$	—

Nine Months Ended September 26, 2020	$	(323)	Interest expense	$	(26)	Interest expense	$	—
Nine Months Ended September 28, 2019	$	(78)	Interest expense	$	496	Interest expense	$	—

Foreign Exchange Derivative Contracts

We operate and sell our products in various global markets. As a result, we are exposed to changes in foreign currency exchange rates. We utilize foreign currency forward contracts to hedge against future movements in foreign exchange rates that affect certain existing foreign currency denominated assets and liabilities and forecasted foreign currency revenue and expense transactions. Under this program, our strategy is to have increases or decreases in our foreign currency exposures mitigated by gains or losses on the foreign currency forward contracts in order to mitigate the risks and volatility associated with foreign currency transaction gains or losses.

We do not use derivative financial instruments for speculative or trading purposes. For accounting purposes, certain of our foreign currency forward contracts are not designated as hedging instruments and, accordingly, we record the fair value of these contracts as of the end of our reporting period in our Condensed Consolidated Balance Sheets with changes in fair value recorded within Other income, net in our Condensed Consolidated Statement of Income for both realized and unrealized gains and losses. Certain of our foreign currency forward contracts are designated as cash flow hedges, and, accordingly, we record the fair value of these contracts as of the end of our reporting period in our Condensed Consolidated Balance Sheets with changes in fair value recorded as a component of Accumulated other comprehensive income (loss) and reclassified into earnings in the same period in which the hedged transaction affects earnings, and in the same line item on the Condensed Consolidated Statements of Income as the impact of the hedge transaction. At September 26, 2020, we expect to reclassify $0.5 million of the amount accumulated in other comprehensive income (loss) to earnings during the next 12 months, due to the recognition in earnings of the hedged forecasted transactions.

The fair value of our foreign exchange derivative contracts was determined based on current foreign currency exchange rates and forward points. All of our foreign exchange derivative contracts outstanding at September 26, 2020 will mature by the third quarter of fiscal 2021.

The following table provides information about our foreign currency forward contracts outstanding as of September 26, 2020 (in thousands):


Currency	Contract Position	Contract Amount (Local Currency)	Contract Amount (U.S. Dollars)
Euro Dollar	Buy	(10,341)	(11,591)
Euro Dollar	Sell	9,835	11,447
Japanese Yen	Sell	2,119,658	20,070
Korean Won	Buy	(3,259,002)	(2,785)


Total USD notional amount of outstanding foreign exchange contracts			$	17,141

Our foreign currency contracts are classified within Level 2 of the fair value hierarchy as they are valued using pricing models that utilize observable market inputs.

The impact of foreign exchange derivative contracts not designated as cash flow hedges on our Condensed Consolidated Statements of Income was as follows (in thousands):


		Amount of Gain (Loss) Recognized on Derivatives
		Three Months Ended				Nine Months Ended
Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized on Derivatives	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Foreign exchange forward contracts	Other income, net	$	529	$	(76)	$	878	$	198

The impact of foreign exchange derivative contracts designated as cash flow hedges on our Condensed Consolidated Statements of Income was as follows (in thousands):


	Amount of Gain (Loss) Recognized in Accumulated OCI on Derivative		Location of Gain (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain (Loss) Reclassified from Accumulated OCI into Income
Three Months Ended September 26, 2020	$	(553)	Cost of revenues	$	150
			Research and development	23
			Selling, general and administrative	63
				$	236

Three Months Ended September 28, 2019	$	(642)	Cost of revenues	$	(126)
			Research and development	(23)
			Selling, general and administrative	(58)
				$	(207)

Nine Months Ended September 26, 2020	$	427	Cost of revenues	$	109
			Research and development	11
			Selling, general and administrative	16
				$	136

Nine Months Ended September 28, 2019	$	(1,096)	Cost of revenues	$	(297)
			Research and development	(42)
			Selling, general and administrative	(109)
				$	(448)

Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis

We measure and report our non-financial assets such as Property, plant and equipment, Goodwill and Intangible assets at fair value on a non-recurring basis if we determine these assets to be impaired or in the period when we make a business acquisition. Other than as discussed in Note 4, Acquisition, there were no assets or liabilities measured at fair value on a nonrecurring basis during the three and nine months ended September 26, 2020 or September 28, 2019.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Warranty

9 Months Ended

Sep. 26, 2020

Product Warranties Disclosures [Abstract]

Warranty

We offer warranties on certain products and record a liability for the estimated future costs associated with warranty claims at the time revenue is recognized. The warranty liability is based upon historical experience and our estimate of the level of future costs. While we engage in product quality programs and processes, our warranty obligation is affected by product failure rates, material usage and service delivery costs. We continuously monitor product returns for warranty and maintain a reserve for the related expenses based upon our historical experience and any specifically identified failures. As we sell new products to our customers, we must exercise considerable judgment in estimating the expected failure rates. This estimating process is based on historical experience of similar products, as well as various other assumptions that we believe to be reasonable under the circumstances. We provide for the estimated cost of product warranties at the time revenue is recognized as a component of Cost of revenues in our Condensed Consolidated Statement of Income.

Changes in our warranty liability were as follows (in thousands):


	Nine Months Ended
	September 26, 2020		September 28, 2019
Balance at beginning of period	$	1,942	$	2,102
Accruals	2,771		2,742
Settlements	(2,838)		(3,051)
Balance at end of period	$	1,875	$	1,793

Property, Plant, and Equipment, net

9 Months Ended

Sep. 26, 2020

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment, net

Property, plant and equipment, net consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Land	$	4,751	$	—
Machinery and equipment	219,908		201,861
Computer equipment and software	36,050		35,192
Furniture and fixtures	7,022		6,756
Leasehold improvements	78,400		76,081
Sub-total	346,131		319,890
Less: Accumulated depreciation and amortization	(287,141)		(273,001)
Net, property, plant and equipment	58,990		46,889
Construction-in-process	38,538		11,858
Total	$	97,528	$	58,747

Stockholders’ Equity and Stock-Based Compensation

9 Months Ended

Sep. 26, 2020

Equity [Abstract]

Stockholders’ Equity and Stock-Based Compensation

Restricted Stock Units

Restricted stock unit ("RSU") activity under our equity incentive plan was as follows:


	Units	Weighted Average Grant Date Fair Value
RSUs at December 28, 2019	3,069,000	$	14.30
Awards granted	1,189,018	25.72
Awards vested	(1,446,481)	13.70
Awards forfeited	(42,384)	14.64
RSUs at September 26, 2020	2,769,153	19.52

Performance Restricted Stock Units

We may grant Performance RSUs ("PRSUs") to certain executives, which vest based upon us achieving certain market performance criteria.

On August 27, 2020, we granted 258,600 PRSUs to certain senior executives for a total grant date fair value of $6.9 million, which will be recognized ratably over the requisite service period. The performance criteria are based on a metric called Total Shareholder Returns ("TSR") for the period of July 1, 2020 - June 30, 2023, relative to the TSR of the companies identified as being part of the S&P semiconductor Select Industry Index (FormFactor peer companies) as of August 27, 2020.

There were no other market based PRSUs granted during the nine months ended September 26, 2020. PRSUs are included as part of the RSU activity above.

Stock Options

Stock option activity under our equity incentive plan was as follows:


	Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life in Years	Aggregate Intrinsic Value
Outstanding at December 28, 2019	361,769	$	8.35

Options exercised	(205,769)	8.32

Outstanding at September 26, 2020	156,000	$	8.38	1.39	$	2,427,060
Vested and expected to vest at September 26, 2020	156,000	$	8.38	1.39	$	2,427,060
Exercisable at September 26, 2020	156,000	$	8.38	1.39	$	2,427,060

Employee Stock Purchase Plan

Information related to activity under our Employee Stock Purchase Plan ("ESPP") was as follows:


	Nine Months Ended
	September 26, 2020
Shares issued	485,566
Weighted average per share purchase price	$	16.47
Weighted average per share discount from the fair value of our common stock on the date of issuance	$	11.00

Stock-Based Compensation

Stock-based compensation was included in our Condensed Consolidated Statements of Income as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Cost of revenues	$	962	$	1,117	$	2,800	$	3,031
Research and development	1,326		1,729		4,154		4,830
Selling, general and administrative	3,221		3,658		9,820		9,227
Total stock-based compensation	$	5,509	$	6,504	$	16,774	$	17,088

Unrecognized Compensation Costs

At September 26, 2020, the unrecognized stock-based compensation was as follows (dollars in thousands):


	Unrecognized Expense		Average Expected Recognition Period in Years

Restricted stock units	$	34,513	2.31
Performance restricted stock units	10,499		2.28
Employee stock purchase plan	993		0.35
Total unrecognized stock-based compensation expense	$	46,005	2.26

Net Income per Share

9 Months Ended

Sep. 26, 2020

Earnings Per Share [Abstract]

Net Income per Share

Net Income per ShareThe following table reconciles the shares used in calculating basic net income per share and diluted net income per share (in thousands):


	Three Months Ended		Nine Months Ended
	September 26, 2020	September 28, 2019	September 26, 2020	September 28, 2019



Weighted-average shares used in computing basic net income per share	77,029	75,280	76,436	74,749
Add potentially dilutive securities	1,780	2,011	2,098	2,014
Weighted-average shares used in computing diluted net income per share	78,809	77,291	78,534	76,763

Securities not included as they would have been antidilutive	264	—	354	23

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 26, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases See Note 14, Leases. Contractual Obligations and Commitments Our contractual obligations and commitments have not materially changed as of September 26, 2020 from those disclosed in our Annual Report on Form 10-K for the year ended December 28, 2019. Legal Matters From time to time, we may be subject to legal proceedings and claims in the ordinary course of business. As of September 26, 2020, and as of the filing of this Quarterly Report on Form 10-Q, we were not involved in any material legal proceedings.

Leases

9 Months Ended

Sep. 26, 2020

Leases [Abstract]

Leases

We lease real estate space under non-cancelable operating lease agreements for commercial and industrial space, as well as for our corporate headquarters located in Livermore, California. Our leases have remaining terms of 1 to 8 years, and some leases include options to extend up to 20 years. We also have operating leases for automobiles with remaining lease terms of 1 to 4 years. We did not include any of our renewal options in our lease terms for calculating our lease liability as the renewal options allow us to maintain operational flexibility and we are not reasonably certain we will exercise these options at this time. The weighted-average remaining lease term for our operating leases was 7 years as of September 26, 2020 and the weighted-average discount rate was 4.52%.

The components of lease expense were as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Lease expense:
Operating lease expense	$	1,818	$	1,726	$	5,536	$	5,205
Short-term lease expense	32		53		94		101
Variable lease expense	372		252		1,159		920
	$	2,222	$	2,031	$	6,789	$	6,226

Future minimum payments under our non-cancelable operating leases were as follows as of September 26, 2020 (in thousands):


Fiscal Year	Amount
Remainder of 2020	$	1,877
2021	6,773
2022	5,549
2023	4,724
2024	4,471
Thereafter	16,272
Total minimum lease payments	39,666
Less: interest	(6,317)
Present value of net minimum lease payments	33,349
Less: current portion	(6,555)
Total long-term operating lease liabilities	$	26,794

Revenue	9 Months Ended
Revenue	Sep. 26, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Transaction price allocated to the remaining performance obligations: On September 26, 2020, we had $3.8 million of remaining performance obligations, which were comprised of deferred service contracts and extended warranty contracts not yet delivered. We expect to recognize approximately 31.9% of our remaining performance obligations as revenue in the remainder of fiscal 2020, approximately 49.9% in fiscal 2021, and approximately 18.2% in fiscal 2022 and thereafter. The foregoing excludes the value of other remaining performance obligations as they have original durations of one year or less, and also excludes information about variable consideration allocated entirely to a wholly unsatisfied performance obligation. Contract balances: The timing of revenue recognition may differ from the timing of invoicing to customers. Accounts receivable is recorded at the invoiced amount, net of an allowance for doubtful accounts. A receivable is recognized in the period we deliver goods or provide services or when our right to consideration is unconditional. A contract asset is recorded when we have performed under the contract but our right to consideration is conditional on something other than the passage of time. Contract assets as of September 26, 2020 and December 28, 2019 were $3.5 million and $0.9 million, respectively, and are reported on the Condensed Consolidated Balance Sheets as a component of Prepaid expenses and other current assets. Contract liabilities include payments received in advance of performance under a contract and are satisfied as the associated revenue is recognized. Contract liabilities are reported on the Condensed Consolidated Balance Sheets at the end of each reporting period as a component of Deferred revenue and Other liabilities. Contract liabilities as of September 26, 2020 and December 28, 2019 were $14.7 million and $10.8 million, respectively. During the nine months ended September 26, 2020, we recognized $8.6 million of revenue, that was included in contract liabilities as of December 28, 2019. Costs to obtain a contract: We generally expense sales commissions when incurred as a component of Selling, general and administrative expense, as the amortization period is typically less than one year. Revenue by Category: Refer to Note 16, Operating Segments and Enterprise-Wide Information, for further details.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

+ Details

Operating Segments and Enterprise-Wide Information

9 Months Ended

Sep. 26, 2020

Segment Reporting [Abstract]

Operating Segments and Enterprise-Wide Information

Our chief operating decision maker ("CODM") is our Chief Executive Officer, who reviews operating results to make decisions about allocating resources and assessing performance for the entire company. We operate in two reportable segments consisting of the Probe Cards segment and the Systems segment. The following table summarizes the operating results by reportable segment (dollars in thousands):


	Three Months Ended
	September 26, 2020												September 28, 2019
	Probe Cards			Systems			Corporate and Other			Total			Probe Cards			Systems			Corporate and Other			Total
Revenues	$	150,773		$	27,223		$	—		$	177,996		$	116,447		$	24,157		$	—		$	140,604
Gross profit	$	69,641		$	13,565		$	(6,457)		$	76,749		$	48,127		$	13,015		$	(5,824)		$	55,318
Gross margin	46.2		%	49.8		%	—		%	43.1		%	41.3		%	53.9		%	—		%	39.3		%


	Nine Months Ended
	September 26, 2020												September 28, 2019
	Probe Cards			Systems			Corporate and Other			Total			Probe Cards			Systems			Corporate and Other			Total
Revenues	$	419,272		$	77,301		$	—		$	496,573		$	338,187		$	72,648		$	—		$	410,835
Gross profit	191,907			37,618			(19,219)			$	210,306		$	141,913		$	38,703		$	(17,425)		$	163,191
Gross margin	45.8		%	48.7		%	—		%	42.4		%	42.0		%	53.3		%	—		%	39.7		%

Operating results provide useful information to our management for assessment of our performance and results of operations. Certain components of our operating results are utilized to determine executive compensation along with other measures.

Corporate and Other includes unallocated expenses relating to amortization of intangible assets, share-based compensation, and restructuring charges, net, which are not used in evaluating the results of, or in allocating resources to, our reportable segments.

Certain revenue category information by reportable segment was as follows (in thousands):


	Three Months Ended
	September 26, 2020						September 28, 2019
	Probe Cards		Systems		Total		Probe Cards		Systems		Total
Market:
Foundry & Logic	$	108,411	$	—	$	108,411	$	68,431	$	—	$	68,431
DRAM	31,379		—		31,379		39,425		—		39,425
Flash	10,983		—		10,983		8,591		—		8,591
Systems	—		27,223		27,223		—		24,157		24,157
Total	$	150,773	$	27,223	$	177,996	$	116,447	$	24,157	$	140,604
Timing of revenue recognition:
Products transferred at a point in time	$	150,252	$	25,987	$	176,239	$	115,324	$	23,561	$	138,885
Services transferred over time	521		1,236		1,757		1,123		596		1,719
Total	$	150,773	$	27,223	$	177,996	$	116,447	$	24,157	$	140,604
Geographical region:
Taiwan	$	33,351	$	3,584	$	36,935	$	16,513	$	1,742	$	18,255
United States	31,596		4,732		36,328		28,400		5,265		33,665
South Korea	28,337		1,234		29,571		22,779		818		23,597
China	24,851		3,695		28,546		24,427		6,956		31,383
Japan	12,288		4,857		17,145		13,640		3,289		16,929
Europe	11,679		5,300		16,979		5,754		3,794		9,548
Asia-Pacific1	5,505		3,449		8,954		3,516		2,149		5,665
Rest of the world	3,166		372		3,538		1,418		144		1,562
Total	$	150,773	$	27,223	$	177,996	$	116,447	$	24,157	$	140,604


	Nine Months Ended
	September 26, 2020						September 28, 2019
	Probe Cards		Systems		Total		Probe Cards		Systems		Total
Market:
Foundry & Logic	$	323,503	$	—	$	323,503	$	213,453	$	—	$	213,453
DRAM	75,127		—		75,127		104,355		—		104,355
Flash	20,642		—		20,642		20,379		—		20,379
Systems	—		77,301		77,301		—		72,648		72,648
Total	$	419,272	$	77,301	$	496,573	$	338,187	$	72,648	$	410,835
Timing of revenue recognition:
Products transferred at a point in time	$	417,529	$	73,393	$	490,922	$	335,054	$	70,831	$	405,885
Services transferred over time	1,743		3,908		5,651		3,133		1,817		4,950
Total	$	419,272	$	77,301	$	496,573	$	338,187	$	72,648	$	410,835
Geographical region:
China	$	107,756	$	13,190	$	120,946	$	58,882	$	14,699	$	73,581
Taiwan	93,596		8,290		101,886		50,596		4,918		55,514
United States	79,575		16,790		96,365		88,127		18,170		106,297
South Korea	56,278		2,494		58,772		75,157		3,334		78,491
Europe	36,656		15,498		52,154		15,601		14,088		29,689
Japan	24,502		11,072		35,574		31,807		11,647		43,454
Asia-Pacific1	14,307		9,010		23,317		12,568		4,043		16,611
Rest of the world	6,602		957		7,559		5,449		1,749		7,198
Total	$	419,272	$	77,301	$	496,573	$	338,187	$	72,648	$	410,835

1 Asia-Pacific includes all countries in the region except China, Japan, South Korea, and Taiwan, which are disclosed separately.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8924-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8721-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8657-108599

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8721-108599

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-URI http://asc.fasb.org/topic&trid=2134510

+ Details

Subsequent Event (Notes)	9 Months Ended
Subsequent Event (Notes)	Sep. 26, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 19, 2020, subsequent to the balance sheet date, we acquired High Precision Devices, Inc., for total cash consideration of $17.0 million, subject to adjustment for changes in working capital and payoff of debt as stipulated in the merger agreement. This acquisition brings highly specialized skills and know-how to address the unique test challenges within the emerging quantum computing, superconducting computing, and ultra-sensitive sensor markets which operate at temperatures as low as 30 millikelvin. The transaction will be accounted for in accordance with the acquisition method of accounting which requires, among other things, that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. Due to the limited time since the acquisition date, the initial purchase allocation for the business combination is incomplete at this time. Disclosures regarding amounts recognized for major classes of assets acquired and liabilities assumed will be provided once the initial accounting is completed. The acquired business is not expected to be material to the Company’s operations and consolidated financial position.

Basis of Presentation and New Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 26, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying condensed consolidated financial information of FormFactor, Inc. is unaudited and has been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). However, such information reflects all adjustments, consisting only of normal recurring adjustments, which are, in the opinion of management, necessary for a fair presentation of the financial position, results of operations and cash flows for the interim periods. The financial information as of December 28, 2019 is derived from our 2019 Annual Report on Form 10-K. The condensed consolidated financial statements included herein should be read in conjunction with the consolidated financial statements and the notes thereto included in our 2019 Annual Report on Form 10-K filed with the SEC on February 21, 2020. The results of operations for the interim periods presented are not necessarily indicative of the results to be expected for the full year.
Fiscal Year	Fiscal Year We operate on a 52/53 week fiscal year, whereby the fiscal year ends on the last Saturday of December. Fiscal 2020 and 2019 each contain 52 weeks and the nine months ended September 26, 2020 and September 28, 2019 each contained 39 weeks. Fiscal 2020 will end on December 26, 2020.
New Accounting Pronouncements	New Accounting Pronouncements ASU 2016-13 In June 2016, the Financial Accounting Standard Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-13, "Measurement of Credit Losses on Financial Instruments (Topic 326)." The provisions of this standard require financial assets measured at amortized cost to be presented at the net amount expected to be collected. An allowance account would be established to present the net carrying value at the amount expected to be collected. ASU 2016-13 also provides that credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses. The guidance was amended through various ASU's subsequent to ASU 2016-13, all of which was effective beginning fiscal 2020. We adopted ASU 2016-13 on a prospective basis on December 29, 2019, the first day of fiscal 2020. The adoption did not have a material effect on our financial position, results of operations or cash flows. ASU 2018-15 In August 2018, the FASB issued ASU 2018-15, "Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." The new guidance clarifies the accounting for implementation costs in cloud computing arrangements. ASU 2018-15 is effective for fiscal years, including interim periods within those fiscal years, beginning after December 15, 2019. We adopted ASU 2018-15 on a prospective basis on December 29, 2019, the first day of fiscal 2020. The adoption did not have a material effect on our financial position, results of operations or cash flows. ASU 2019-12 In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740),” which simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption of the amendments is permitted, including adoption in any interim period for which financial statements have not yet been issued. Depending on the amendment, adoption may be applied on the retrospective, modified retrospective or prospective basis. We have not yet determined the impact of this standard on our financial position, results of operations or cash flows. ASU 2020-04 In March 2020, the FASB issued ASU 2020-04, "Referenced Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting." The amendments in this update apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. The amendments in this update are elective and are effective upon issuance for all entities. We have not yet evaluated the transition approach for our LIBOR indexed contracts and have not determined whether we will be electing such expedients and exceptions. Release No. 33-10786 In May 2020, the SEC issued Final Rule Release No. 33-10786, which amends the financial statement requirements for acquisitions and dispositions of businesses and related pro forma financial information required under SEC Regulation S-X, Rule 3-05. The final rule modifies the significance test required in SEC Regulation S-X, Rule 1-02(w) by raising the significance threshold for reporting dispositions of a business from 10% to 20% and by modifying the calculation of the investment and income tests. The modifications are effective for fiscal years starting after December 31, 2020 with early adoption permitted. We early adopted these modifications on June 28, 2020, the first day of the third quarter.
Fair Value Policy	Whenever possible, the fair values of our financial assets and liabilities are determined using quoted market prices of identical securities or quoted market prices of similar securities from active markets. The three levels of inputs that may be used to measure fair value are as follows: •Level 1 valuations are obtained from real-time quotes for transactions in active exchange markets involving identical securities; •Level 2 valuations utilize significant observable inputs, such as quoted prices for similar assets or liabilities, quoted prices near the reporting date in markets that are less active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and •Level 3 valuations utilize unobservable inputs to the valuation methodology and include our own data about assumptions market participants would use in pricing the asset or liability based on the best information available under the circumstances. We did not have any transfers of assets or liabilities measured at fair value on a recurring basis to or from Level 1, Level 2 or Level 3 during the three and nine months ended September 26, 2020 or the year ended December 28, 2019. The carrying values of Cash, Accounts receivable, net, Restricted cash, Prepaid expenses and other current assets, Accounts payable, Accrued liabilities, and Current portion of term loans, net of unamortized issuance costs, approximate fair value due to their short maturities. No changes were made to our valuation techniques during the first nine months of fiscal 2020. Assets and Liabilities Measured at Fair Value on a Non-Recurring BasisWe measure and report our non-financial assets such as Property, plant and equipment, Goodwill and Intangible assets at fair value on a non-recurring basis if we determine these assets to be impaired or in the period when we make a business acquisition. Other than as discussed in Note 4, Acquisition, t

Concentration of Credit and Other Risks (Tables)

9 Months Ended

Sep. 26, 2020

Risks and Uncertainties [Abstract]

Schedule of Customer Percentage of Revenue

Each of the following customers accounted for 10% or more of our revenues for the periods indicated:


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Intel Corporation	25.6	%	23.9	%	32.4	%	23.8	%
Taiwan Semiconductor Manufacturing Co.,LTD.	10.6	%	*		*		*
Samsung Electronics., LTD.	10.6	%	*		*		10.0	%
Micron Technology, Inc.	10.1	%	11.9	%	*		*
SK Hynix Inc.	*		13.5	%	*		10.6	%
	56.9	%	49.3	%	32.4	%	44.4	%

*Represents less than 10% of total revenues.

Inventories (Tables)

9 Months Ended

Sep. 26, 2020

Inventory Disclosure [Abstract]

Schedule of Inventory Components

Inventories, net, consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Raw materials	$	44,586	$	38,528
Work-in-progress	32,770		29,720
Finished goods	17,260		15,010
	$	94,616	$	83,258

Acquisition (Tables)

9 Months Ended

Sep. 26, 2020

Business Combinations [Abstract]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

We finalized our allocation of the assets acquired, including goodwill and intangibles, and liabilities assumed for the purchase as follows (in thousands):


	Amount
Cash and cash equivalents	$	1,687
Accounts receivable	3,079
Inventory	2,643
Property, plant and equipment	696
Operating lease, right of use assets	335
Prepaid expenses and other current assets	838
Tangible assets acquired	9,278
Customer deposits	(1,933)
Accounts payable and accrued liabilities	(1,182)
Operating lease liabilities	(335)
Deferred tax liabilities	(5,757)
Total tangible assets acquired and liabilities assumed	71
Intangible assets	17,429
Goodwill	11,123
Net Assets Acquired	$	28,623

The total estimated purchase price would be allocated to the underlying assets acquired and liabilities assumed based on the provisional amounts, as follows (in thousands):


	Amount
Accounts receivable	$	4,365
Inventory	2,318
Property, plant and equipment	9,053
Operating lease, right of use assets	519
Prepaid expenses and other current assets	317
Tangible assets acquired	16,572

Accounts payable and accrued liabilities	(572)
Operating lease liabilities	(519)

Total tangible assets acquired and liabilities assumed	15,481

Goodwill	19,519
Net Assets Acquired	$	35,000

Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination

The intangible assets as of the closing date of the acquisition included (in thousands):


	Amount		Weighted Average Useful Life (in years)
Developed technologies	$	12,505	8.0
Customer relationships	3,071		6.0
Backlog	1,645		0.5
Trade names	208		2.0
Total intangible assets	$	17,429	7.0

Goodwill and Intangible Assets (Tables)

9 Months Ended

Sep. 26, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill by Reportable Segments

Goodwill by reportable segment was as follows (in thousands):


	Probe Cards		Systems		Total
Goodwill, gross, as of December 29, 2018	$	172,482	$	16,732	$	189,214
Addition - FRT GmbH Acquisition	—		10,148		10,148
Foreign currency translation	—		(166)		(166)
Goodwill, gross, as of December 28, 2019	172,482		26,714		199,196
Addition - FRT GmbH Acquisition	—		975		975
Addition - Baldwin Park Acquisition	19,519		—		19,519
Foreign currency translation	—		1,067		1,067
Goodwill, gross, as of September 26, 2020	$	192,001	$	28,756	$	220,757

Schedule of Intangible Assets

Intangible assets were as follows (in thousands):


	September 26, 2020						December 28, 2019
Intangible Assets	Gross		Accumulated Amortization		Net		Gross		Accumulated Amortization		Net
Developed technologies	$	156,659	$	131,289	$	25,370	$	154,951	$	116,138	$	38,813
Trade names	7,870		7,231		639		7,816		6,976		840
Customer relationships	43,460		31,532		11,928		44,229		27,057		17,172
Backlog	1,744		1,744		—		1,676		891		785
	$	209,733	$	171,796	$	37,937	$	208,672	$	151,062	$	57,610

Schedule of Amortization Expense

Amortization expense was included in our Condensed Consolidated Statements of Income as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Cost of revenues	$	4,985	$	4,707	$	15,661	$	14,137
Selling, general and administrative	1,547		1,372		4,588		6,111
	$	6,532	$	6,079	$	20,249	$	20,248

Schedule of Estimated Amortization of Intangible Assets

The estimated future amortization of intangible assets is as follows (in thousands):


Fiscal Year	Amount
Remainder of 2020	$	6,105
2021	14,945
2022	5,708
2023	3,954
2024	2,200
Thereafter	5,025
	$	37,937

Debt (Tables)

9 Months Ended

Sep. 26, 2020

Debt Disclosure [Abstract]

Schedule of Debt

Our debt consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Term loans	$	36,070	$	58,514
Less unamortized issuance costs	(76)		(29)
Term loans less issuance costs	$	35,994	$	58,485

Schedule of Maturities of Long-term Debt

Future principal and interest payments on our term loans as of September 26, 2020, based on the interest rate in effect at that date were as follows (in thousands):


	Payments Due In Fiscal Year
	Remainder 2020		2021		2022		2023		2024		Thereafter		Total
Term loans - principal payments	$	2,278	$	9,133	$	9,161	$	1,050	$	1,080	$	13,368	$	36,070
Term loans - interest payments (1)	145		503		377		290		271		1,433		3,019
Total	$	2,423	$	9,636	$	9,538	$	1,340	$	1,351	$	14,801	$	39,089

(1) Represents our minimum interest payment commitments at 1.91% per annum for the Building Term Loan and 1.30% per annum for the FRT Term Loan.

Accrued Liabilities (Tables)

9 Months Ended

Sep. 26, 2020

Payables and Accruals [Abstract]

Schedule of Accrued Liabilities [Table Text Block]

Accrued liabilities consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Accrued compensation and benefits	$	28,273	$	21,329
Accrued income and other taxes	5,989		6,846
Accrued warranty	1,875		1,942
Accrued employee stock purchase plan contributions withheld	1,648		3,331
Accrued contingent consideration	2,966		—
Other accrued expenses	3,275		2,991
	$	44,026	$	36,439

Fair Value and Derivative Instruments (Tables)

9 Months Ended

Sep. 26, 2020

Fair Value Disclosures [Abstract]

Fair Value Assets Measured on Recurring Basis

Assets and liabilities measured at fair value on a recurring basis were as follows (in thousands):


September 26, 2020	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	71,663	$	—	$	—	$	71,663



Marketable securities:
U.S. treasuries	34,198		—		—		34,198
Certificates of deposit	—		2,428		—		2,428
U.S. agency securities	—		2,083		—		2,083
Corporate bonds	—		17,391		—		17,391

	34,198		21,902		—		56,100
Foreign exchange derivative contracts	—		470		—		470

Total assets	$	105,861	$	22,372	$	—	$	128,233
Liabilities:

Interest rate swap derivative contracts	$	—	$	(271)	$	—	$	(271)
Contingent consideration	—		—		(2,966)		(2,966)
Total liabilities	$	—	$	(271)	$	(2,966)	$	(3,237)


December 28, 2019	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	17,056	$	—	$	—	$	17,056


Marketable securities:
U.S. treasuries	10,468		—		—		10,468
Certificates of deposit	—		3,590		—		3,590
U.S. agency securities	—		24,430		—		24,430
Corporate bonds	—		33,928		—		33,928
Commercial paper	—		3,911		—		3,911
	10,468		65,859		—		76,327
Foreign exchange derivative contracts	—		41		—		41
Interest rate swap derivative contracts	—		26		—		26
Total assets	$	27,524	$	65,926	$	—	$	93,450
Liabilities:
Foreign exchange derivative contracts	$	—	$	(240)	$	—	$	(240)
Contingent consideration	—		—		(5,364)		(5,364)
Total liabilities	$	—	$	(240)	$	(5,364)	$	(5,604)

Schedule of the Impact of Cash Flow Hedges on Consolidated Financial Statements

The impact of the interest rate swaps on our Condensed Consolidated Statements of Income was as follows (in thousands):


	Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)		Location of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		Location of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)
Three Months Ended September 26, 2020	$	(53)	Interest expense	$	(38)	Interest expense	$	—
Three Months Ended September 28, 2019	$	12	Interest expense	$	113	Interest expense	$	—

Nine Months Ended September 26, 2020	$	(323)	Interest expense	$	(26)	Interest expense	$	—
Nine Months Ended September 28, 2019	$	(78)	Interest expense	$	496	Interest expense	$	—

Schedule of Foreign Currency Forward Contracts

The following table provides information about our foreign currency forward contracts outstanding as of September 26, 2020 (in thousands):


Currency	Contract Position	Contract Amount (Local Currency)	Contract Amount (U.S. Dollars)
Euro Dollar	Buy	(10,341)	(11,591)
Euro Dollar	Sell	9,835	11,447
Japanese Yen	Sell	2,119,658	20,070
Korean Won	Buy	(3,259,002)	(2,785)


Total USD notional amount of outstanding foreign exchange contracts			$	17,141

The impact of foreign exchange derivative contracts designated as cash flow hedges on our Condensed Consolidated Statements of Income was as follows (in thousands):


	Amount of Gain (Loss) Recognized in Accumulated OCI on Derivative		Location of Gain (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain (Loss) Reclassified from Accumulated OCI into Income
Three Months Ended September 26, 2020	$	(553)	Cost of revenues	$	150
			Research and development	23
			Selling, general and administrative	63
				$	236

Three Months Ended September 28, 2019	$	(642)	Cost of revenues	$	(126)
			Research and development	(23)
			Selling, general and administrative	(58)
				$	(207)

Nine Months Ended September 26, 2020	$	427	Cost of revenues	$	109
			Research and development	11
			Selling, general and administrative	16
				$	136

Nine Months Ended September 28, 2019	$	(1,096)	Cost of revenues	$	(297)
			Research and development	(42)
			Selling, general and administrative	(109)
				$	(448)

Schedule of Gains and Losses Related to Non-designated Derivative Instruments

The impact of foreign exchange derivative contracts not designated as cash flow hedges on our Condensed Consolidated Statements of Income was as follows (in thousands):


		Amount of Gain (Loss) Recognized on Derivatives
		Three Months Ended				Nine Months Ended
Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized on Derivatives	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Foreign exchange forward contracts	Other income, net	$	529	$	(76)	$	878	$	198

Warranty (Tables)

9 Months Ended

Sep. 26, 2020

Product Warranties Disclosures [Abstract]

Reconciliation of Changes in Warranty Liability

Changes in our warranty liability were as follows (in thousands):


	Nine Months Ended
	September 26, 2020		September 28, 2019
Balance at beginning of period	$	1,942	$	2,102
Accruals	2,771		2,742
Settlements	(2,838)		(3,051)
Balance at end of period	$	1,875	$	1,793

Property, Plant, and Equipment, net (Tables)

9 Months Ended

Sep. 26, 2020

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, plant and equipment, net consisted of the following (in thousands):


	September 26, 2020		December 28, 2019
Land	$	4,751	$	—
Machinery and equipment	219,908		201,861
Computer equipment and software	36,050		35,192
Furniture and fixtures	7,022		6,756
Leasehold improvements	78,400		76,081
Sub-total	346,131		319,890
Less: Accumulated depreciation and amortization	(287,141)		(273,001)
Net, property, plant and equipment	58,990		46,889
Construction-in-process	38,538		11,858
Total	$	97,528	$	58,747

Stockholders’ Equity and Stock-Based Compensation (Tables)

9 Months Ended

Sep. 26, 2020

Equity [Abstract]

Schedule of Restricted Stock Unit Activity

Restricted stock unit ("RSU") activity under our equity incentive plan was as follows:


	Units	Weighted Average Grant Date Fair Value
RSUs at December 28, 2019	3,069,000	$	14.30
Awards granted	1,189,018	25.72
Awards vested	(1,446,481)	13.70
Awards forfeited	(42,384)	14.64
RSUs at September 26, 2020	2,769,153	19.52

Schedule of Stock Option Activity

Stock option activity under our equity incentive plan was as follows:


	Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life in Years	Aggregate Intrinsic Value
Outstanding at December 28, 2019	361,769	$	8.35

Options exercised	(205,769)	8.32

Outstanding at September 26, 2020	156,000	$	8.38	1.39	$	2,427,060
Vested and expected to vest at September 26, 2020	156,000	$	8.38	1.39	$	2,427,060
Exercisable at September 26, 2020	156,000	$	8.38	1.39	$	2,427,060

Schedule of ESPP Activity

Information related to activity under our Employee Stock Purchase Plan ("ESPP") was as follows:


	Nine Months Ended
	September 26, 2020
Shares issued	485,566
Weighted average per share purchase price	$	16.47
Weighted average per share discount from the fair value of our common stock on the date of issuance	$	11.00

Schedule of Stock-based Compensation

Stock-based compensation was included in our Condensed Consolidated Statements of Income as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Cost of revenues	$	962	$	1,117	$	2,800	$	3,031
Research and development	1,326		1,729		4,154		4,830
Selling, general and administrative	3,221		3,658		9,820		9,227
Total stock-based compensation	$	5,509	$	6,504	$	16,774	$	17,088

Schedule of Unrecognized Stock-based Compensation

At September 26, 2020, the unrecognized stock-based compensation was as follows (dollars in thousands):


	Unrecognized Expense		Average Expected Recognition Period in Years

Restricted stock units	$	34,513	2.31
Performance restricted stock units	10,499		2.28
Employee stock purchase plan	993		0.35
Total unrecognized stock-based compensation expense	$	46,005	2.26

Net Income per Share (Tables)

9 Months Ended

Sep. 26, 2020

Earnings Per Share [Abstract]

Schedule of Calculation of Numerator and Denominator in Earnings Per Share

The following table reconciles the shares used in calculating basic net income per share and diluted net income per share (in thousands):


	Three Months Ended		Nine Months Ended
	September 26, 2020	September 28, 2019	September 26, 2020	September 28, 2019



Weighted-average shares used in computing basic net income per share	77,029	75,280	76,436	74,749
Add potentially dilutive securities	1,780	2,011	2,098	2,014
Weighted-average shares used in computing diluted net income per share	78,809	77,291	78,534	76,763

Securities not included as they would have been antidilutive	264	—	354	23

Leases (Tables)

9 Months Ended

Sep. 26, 2020

Leases [Abstract]

Components of Lease Expense

The components of lease expense were as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Lease expense:
Operating lease expense	$	1,818	$	1,726	$	5,536	$	5,205
Short-term lease expense	32		53		94		101
Variable lease expense	372		252		1,159		920
	$	2,222	$	2,031	$	6,789	$	6,226

Schedule of Future Minimum Payments Under Leases

Future minimum payments under our non-cancelable operating leases were as follows as of September 26, 2020 (in thousands):


Fiscal Year	Amount
Remainder of 2020	$	1,877
2021	6,773
2022	5,549
2023	4,724
2024	4,471
Thereafter	16,272
Total minimum lease payments	39,666
Less: interest	(6,317)
Present value of net minimum lease payments	33,349
Less: current portion	(6,555)
Total long-term operating lease liabilities	$	26,794

Operating Segments and Enterprise-Wide Information (Tables)

9 Months Ended

Sep. 26, 2020

Segment Reporting [Abstract]

Schedule of Operating Results by Segment

The following table summarizes the operating results by reportable segment (dollars in thousands):


	Three Months Ended
	September 26, 2020												September 28, 2019
	Probe Cards			Systems			Corporate and Other			Total			Probe Cards			Systems			Corporate and Other			Total
Revenues	$	150,773		$	27,223		$	—		$	177,996		$	116,447		$	24,157		$	—		$	140,604
Gross profit	$	69,641		$	13,565		$	(6,457)		$	76,749		$	48,127		$	13,015		$	(5,824)		$	55,318
Gross margin	46.2		%	49.8		%	—		%	43.1		%	41.3		%	53.9		%	—		%	39.3		%


	Nine Months Ended
	September 26, 2020												September 28, 2019
	Probe Cards			Systems			Corporate and Other			Total			Probe Cards			Systems			Corporate and Other			Total
Revenues	$	419,272		$	77,301		$	—		$	496,573		$	338,187		$	72,648		$	—		$	410,835
Gross profit	191,907			37,618			(19,219)			$	210,306		$	141,913		$	38,703		$	(17,425)		$	163,191
Gross margin	45.8		%	48.7		%	—		%	42.4		%	42.0		%	53.3		%	—		%	39.7		%

Disaggregation of Revenue by Segment

Certain revenue category information by reportable segment was as follows (in thousands):


	Three Months Ended
	September 26, 2020						September 28, 2019
	Probe Cards		Systems		Total		Probe Cards		Systems		Total
Market:
Foundry & Logic	$	108,411	$	—	$	108,411	$	68,431	$	—	$	68,431
DRAM	31,379		—		31,379		39,425		—		39,425
Flash	10,983		—		10,983		8,591		—		8,591
Systems	—		27,223		27,223		—		24,157		24,157
Total	$	150,773	$	27,223	$	177,996	$	116,447	$	24,157	$	140,604
Timing of revenue recognition:
Products transferred at a point in time	$	150,252	$	25,987	$	176,239	$	115,324	$	23,561	$	138,885
Services transferred over time	521		1,236		1,757		1,123		596		1,719
Total	$	150,773	$	27,223	$	177,996	$	116,447	$	24,157	$	140,604
Geographical region:
Taiwan	$	33,351	$	3,584	$	36,935	$	16,513	$	1,742	$	18,255
United States	31,596		4,732		36,328		28,400		5,265		33,665
South Korea	28,337		1,234		29,571		22,779		818		23,597
China	24,851		3,695		28,546		24,427		6,956		31,383
Japan	12,288		4,857		17,145		13,640		3,289		16,929
Europe	11,679		5,300		16,979		5,754		3,794		9,548
Asia-Pacific1	5,505		3,449		8,954		3,516		2,149		5,665
Rest of the world	3,166		372		3,538		1,418		144		1,562
Total	$	150,773	$	27,223	$	177,996	$	116,447	$	24,157	$	140,604


	Nine Months Ended
	September 26, 2020						September 28, 2019
	Probe Cards		Systems		Total		Probe Cards		Systems		Total
Market:
Foundry & Logic	$	323,503	$	—	$	323,503	$	213,453	$	—	$	213,453
DRAM	75,127		—		75,127		104,355		—		104,355
Flash	20,642		—		20,642		20,379		—		20,379
Systems	—		77,301		77,301		—		72,648		72,648
Total	$	419,272	$	77,301	$	496,573	$	338,187	$	72,648	$	410,835
Timing of revenue recognition:
Products transferred at a point in time	$	417,529	$	73,393	$	490,922	$	335,054	$	70,831	$	405,885
Services transferred over time	1,743		3,908		5,651		3,133		1,817		4,950
Total	$	419,272	$	77,301	$	496,573	$	338,187	$	72,648	$	410,835
Geographical region:
China	$	107,756	$	13,190	$	120,946	$	58,882	$	14,699	$	73,581
Taiwan	93,596		8,290		101,886		50,596		4,918		55,514
United States	79,575		16,790		96,365		88,127		18,170		106,297
South Korea	56,278		2,494		58,772		75,157		3,334		78,491
Europe	36,656		15,498		52,154		15,601		14,088		29,689
Japan	24,502		11,072		35,574		31,807		11,647		43,454
Asia-Pacific1	14,307		9,010		23,317		12,568		4,043		16,611
Rest of the world	6,602		957		7,559		5,449		1,749		7,198
Total	$	419,272	$	77,301	$	496,573	$	338,187	$	72,648	$	410,835

1 Asia-Pacific includes all countries in the region except China, Japan, South Korea, and Taiwan, which are disclosed separately.

Basis of Presentation and New Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 26, 2020	Sep. 26, 2020	Dec. 25, 2022	Dec. 25, 2021	Dec. 28, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Performance obligations		$ 3.8
Contract assets		3.5			$ 0.9
Contract liabilities		14.7			$ 10.8
Revenue recognized included in contracts		$ 8.6
Forecast
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Expected to be recognized	31.90%		18.20%	49.90%

Basis of Presentation and New Accounting Pronouncements - ASU 2016-18 Information (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019	Sep. 28, 2019	Dec. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents as previously reported in the Condensed Consolidated Statements of Cash Flows	$ 185,368	$ 144,545
Current assets - Restricted cash	1,477	1,981
Restricted cash	1,398	1,411
Cash, cash equivalents and restricted cash as currently reported in the Condensed Consolidated Statements of Cash Flows	$ 188,243	$ 147,937	$ 124,740	$ 100,546

Concentration of Credit and Other Risks (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Revenue from Contract with Customer Benchmark
Concentration Risk [Line Items]
Concentration risk percentage	56.90%	49.30%	32.40%	44.40%
Revenue from Contract with Customer Benchmark \| Intel Corporation
Concentration Risk [Line Items]
Concentration risk percentage	25.60%	23.90%	32.40%	23.80%
Revenue from Contract with Customer Benchmark \| Taiwan Semiconductor Manufacturing Co.,LTD.
Concentration Risk [Line Items]
Concentration risk percentage	10.60%
Revenue from Contract with Customer Benchmark \| Samsung Electronics., LTD.
Concentration Risk [Line Items]
Concentration risk percentage	10.60%			10.00%
Revenue from Contract with Customer Benchmark \| Micron Technology, Inc.
Concentration Risk [Line Items]
Concentration risk percentage	10.10%	11.90%
Revenue from Contract with Customer Benchmark \| SK Hynix Inc.
Concentration Risk [Line Items]
Concentration risk percentage		13.50%		10.60%
Accounts Receivable \| Major Customer 1
Concentration Risk [Line Items]
Concentration risk percentage			26.60%		25.70%
Accounts Receivable \| Major Customer 2
Concentration Risk [Line Items]
Concentration risk percentage			18.30%		15.10%
Accounts Receivable \| Major Customer 3
Concentration Risk [Line Items]
Concentration risk percentage					11.50%

Inventories (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 44,586	$ 38,528
Work-in-progress	32,770	29,720
Finished goods	17,260	15,010
Inventories	$ 94,616	$ 83,258

Acquisition - Additional Information (Details)			3 Months Ended	9 Months Ended
Acquisition - Additional Information (Details)	Jul. 30, 2020 USD ($)	Oct. 09, 2019 USD ($)	Sep. 26, 2020 USD ($)	Sep. 26, 2020 USD ($)	Sep. 28, 2019 USD ($)	Dec. 28, 2019 USD ($)	Oct. 25, 2019 USD ($)	Oct. 09, 2019 EUR (€)
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 22,200,000		$ 34,999,000	$ 0
Contingent consideration, liability			$ 2,966,000	2,966,000		$ 5,364,000
Amortization, inventory step-up adjustment			500,000	500,000
Fair Value, Inputs, Level 3 [Member]
Business Acquisition [Line Items]
Contingent consideration, liability		$ 6,500,000	2,966,000	2,966,000		$ 5,364,000
FRT Term Loan
Business Acquisition [Line Items]
Debt instrument, face amount							$ 23,400,000
FRT
Business Acquisition [Line Items]
Business Acquisition, percentage acquired		100.00%						100.00%
Cash and cash equivalents		$ 1,687,000
Contingent Consideration, Calculation Amount, Multiple of EBIT		150.00%
FRT \| Selling, general and administrative
Business Acquisition [Line Items]
Transaction costs			$ 26,900,000	$ 26,900,000
FRT \| Maximum
Business Acquisition [Line Items]
Contingent consideration, liability \| €								€ 10,300,000
FRT \| Minimum
Business Acquisition [Line Items]
Contingent consideration, liability \| €								€ 0
Baldwin Park
Business Acquisition [Line Items]
Consideration transferred	$ 35,000,000

Acquisition - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Jul. 30, 2020	Dec. 28, 2019	Oct. 09, 2019	Dec. 29, 2018
Business Acquisition [Line Items]
Goodwill	$ 220,757		$ 199,196		$ 189,214
FRT
Business Acquisition [Line Items]
Cash and cash equivalents				$ 1,687
Accounts receivable				3,079
Inventory				2,643
Property, plant and equipment				696
Operating lease, right of use assets				335
Prepaid expenses and other current assets				838
Tangible assets acquired				9,278
Customer deposits				(1,933)
Accounts payable and accrued liabilities				(1,182)
Operating lease liabilities				(335)
Deferred tax liabilities				(5,757)
Total tangible assets acquired and liabilities assumed				71
Intangible assets				17,429
Goodwill				11,123
Net Assets Acquired				$ 28,623
Baldwin Park
Business Acquisition [Line Items]
Accounts receivable		$ 4,365
Inventory		2,318
Property, plant and equipment		9,053
Operating lease, right of use assets		519
Prepaid expenses and other current assets		317
Tangible assets acquired		16,572
Accounts payable and accrued liabilities		(572)
Operating lease liabilities		(519)
Total tangible assets acquired and liabilities assumed		15,481
Goodwill		19,519
Net Assets Acquired		$ 35,000

Acquisition - Intangible Assets Acquired (Details) - FRT $ in Thousands	Oct. 09, 2019 USD ($)
Business Acquisition [Line Items]
Intangible assets	$ 17,429
Weighted Average Useful Life (in years)	7 years
Developed technologies
Business Acquisition [Line Items]
Amount	$ 12,505
Weighted Average Useful Life (in years)	8 years
Customer relationships
Business Acquisition [Line Items]
Amount	$ 3,071
Weighted Average Useful Life (in years)	6 years
Backlog
Business Acquisition [Line Items]
Amount	$ 1,645
Weighted Average Useful Life (in years)	6 months
Trade names
Business Acquisition [Line Items]
Amount	$ 208
Weighted Average Useful Life (in years)	2 years

Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 199,196	$ 189,214
Foreign currency translation	1,067	(166)
Goodwill, ending balance	220,757	199,196
FRT GmbH
Goodwill [Roll Forward]
Goodwill, Acquired During Period	975	10,148
Baldwin Park
Goodwill [Roll Forward]
Goodwill, Acquired During Period	19,519
Probe Cards
Goodwill [Roll Forward]
Goodwill, beginning balance	172,482	172,482
Foreign currency translation	0	0
Goodwill, ending balance	192,001	172,482
Probe Cards \| FRT GmbH
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0	0
Probe Cards \| Baldwin Park
Goodwill [Roll Forward]
Goodwill, Acquired During Period	19,519
Systems
Goodwill [Roll Forward]
Goodwill, beginning balance	26,714	16,732
Foreign currency translation	1,067	(166)
Goodwill, ending balance	28,756	26,714
Systems \| FRT GmbH
Goodwill [Roll Forward]
Goodwill, Acquired During Period	975	$ 10,148
Systems \| Baldwin Park
Goodwill [Roll Forward]
Goodwill, Acquired During Period	$ 0

Goodwill and Intangible Assets - Additional information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, impairment loss	$ 0	$ 0

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	$ 209,733	$ 208,672
Accumulated Amortization	171,796	151,062
Intangible Assets, Net	37,937	57,610
Developed technologies
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	156,659	154,951
Accumulated Amortization	131,289	116,138
Intangible Assets, Net	25,370	38,813
Trade names
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	7,870	7,816
Accumulated Amortization	7,231	6,976
Intangible Assets, Net	639	840
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	43,460	44,229
Accumulated Amortization	31,532	27,057
Intangible Assets, Net	11,928	17,172
Backlog
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross	1,744	1,676
Accumulated Amortization	1,744	891
Intangible Assets, Net	$ 0	$ 785

Goodwill and Intangible Assets - Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Property, Plant and Equipment [Line Items]
Amortization of intangible assets	$ 6,532	$ 6,079	$ 20,249	$ 20,248
Finite-Lived Intangible Assets, Net, Amortization Expense, Rolling Maturity [Abstract]
Remainder of 2020	6,105		6,105
2021	14,945		14,945
2022	5,708		5,708
2023	3,954		3,954
2024	2,200		2,200
Thereafter	5,025		5,025
Intangible Assets, Net	37,937		37,937		$ 57,610
Cost of revenues
Property, Plant and Equipment [Line Items]
Amortization of intangible assets	4,985	4,707	15,661	14,137
Selling, general and administrative
Property, Plant and Equipment [Line Items]
Amortization of intangible assets	$ 1,547	$ 1,372	$ 4,588	$ 6,111

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Debt Disclosure [Abstract]
Term loans	$ 36,070	$ 58,514
Less unamortized issuance costs	(76)	(29)
Term loans less issuance costs	$ 35,994	$ 58,485

Debt - Maturity Schedule (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Debt Instrument [Line Items]
Principal payments - Remainder of 2020	$ 2,278
Principal payments - 2021	9,133
Principal payments - 2022	9,161
Principal payments - 2023	1,050
Principal payments - 2024	1,080
Principal payments - Thereafter	13,368
Term loans	36,070	$ 58,514
Interest payments - Remainder of 2020	145
Interest payments - 2021	503
Interest payments - 2022	377
Interest payments - 2023	290
Interest payments - 2024	271
Interest payments - Thereafter	1,433
Interest payments - Total	3,019
Remainder 2020	2,423
2021	9,636
2022	9,538
2023	1,340
2024	1,351
Thereafter	14,801
Total	$ 39,089
Building Term Loan [Member] \| Minimum
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.91%
FRT Term Loan \| Minimum
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.30%

Debt - CMI Term Loan (Details) - USD ($)		9 Months Ended
Debt - CMI Term Loan (Details) - USD ($)	Jun. 24, 2016	Sep. 26, 2020	Dec. 28, 2019
Debt Instrument [Line Items]
Long-term Debt		$ 35,994,000	$ 58,485,000
CMI Term Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 150,000,000
Debt Instrument, Interest Payment Period	5 years
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months, Percentage	5.00%
Long-term Debt, Maturities, Repayments of Principal in Year Two, Percentage	10.00%
Long-term Debt, Maturities, Repayments of Principal in Year Three, Percentage	20.00%
Long-term Debt, Maturities, Repayments of Principal in Year Four, Percentage	30.00%
Long-term Debt, Maturities, Repayments of Principal in Year Five, Percentage	35.00%
CMI Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%	2.00%
CMI Term Loan [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%

Debt - FRT Term Loan (Details) - USD ($)	Oct. 25, 2019	Sep. 26, 2020	Dec. 28, 2019
Debt Instrument [Line Items]
Long-term Debt		$ 35,994,000	$ 58,485,000
FRT Term Loan
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 23,400,000
Line of Credit Facility, Expiration Period	3 years
Long-Term Line of Credit, Quarterly Repayment Amount	$ 2,000,000.0
Line of Credit Facility, Interest Rate at Period End		1.30%
Long-term Debt		$ 18,300,000
FRT Term Loan \| Euro Interbank Offered Rate [Member]
Debt Instrument [Line Items]
Derivative, Basis Spread on Variable Rate	1.75%

Debt - Building Term Loan (Details) - USD ($)	Jun. 22, 2020	Mar. 17, 2020	Sep. 26, 2020	Dec. 28, 2019
Debt Instrument [Line Items]
Long-term Debt			$ 35,994,000	$ 58,485,000
Building Term Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 18,000,000.0
Long-term Debt, Term	15 years
Debt Instrument, Interest Payment Term	15 years
Line of Credit Facility, Interest Rate at Period End			1.91%
Debt Instrument, Interest Rate, Effective Percentage		2.75%
Long-term Debt			$ 17,800,000
Derivative, Floor Interest Rate Term		1 year
Building Term Loan [Member] \| Interest Rate Contract [Member]
Debt Instrument [Line Items]
Derivative, notional amount		$ 18,000,000.0	$ 17,800,000
Derivative, Floor Interest Rate		0.00%
Building Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%	1.75%

Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Payables and Accruals [Abstract]
Accrued compensation and benefits	$ 28,273	$ 21,329
Accrued warranty	1,648	3,331
Accrued contingent consideration	2,966	0
Accrued employee stock purchase plan contributions withheld	1,875	1,942
Accrued income and other taxes	5,989	6,846
Other accrued expenses	3,275	2,991
Accrued liabilities	$ 44,026	$ 36,439

Fair Value and Derivative Instruments - Fair Value Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019	Oct. 09, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	$ 56,100
Total assets measured at fair value	128,233	$ 93,450
Contingent consideration, liability	2,966	5,364
Liabilities measured at fair value on recurring basis	3,237	5,604
Foreign exchange derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities		76,327
Derivative contracts	470	(41)
Derivative Liability		240
Interest rate swap derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative contracts		26
Derivative Liability	(271)
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	71,663	17,056
U.S. treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	34,198	10,468
Certificates of deposit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	2,428	3,590
U.S. agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	2,083	24,430
Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	17,391	33,928
Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities		3,911
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	34,198
Total assets measured at fair value	105,861	27,524
Level 1 \| Foreign exchange derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities		10,468
Derivative contracts	0
Level 1 \| Interest rate swap derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative contracts		0
Level 1 \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	71,663	17,056
Level 1 \| U.S. treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	34,198	10,468
Level 1 \| Certificates of deposit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	0	0
Level 1 \| U.S. agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	0	0
Level 1 \| Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	0	0
Level 1 \| Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities		0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	21,902
Total assets measured at fair value	22,372	65,926
Liabilities measured at fair value on recurring basis	271	240
Level 2 \| Foreign exchange derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities		65,859
Derivative contracts	470	(41)
Derivative Liability		240
Level 2 \| Interest rate swap derivative contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative contracts		26
Derivative Liability	(271)
Level 2 \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Level 2 \| U.S. treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	0	0
Level 2 \| Certificates of deposit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	2,428	3,590
Level 2 \| U.S. agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	2,083	24,430
Level 2 \| Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities	17,391	33,928
Level 2 \| Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities		3,911
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration, liability	2,966	5,364	$ 6,500
Liabilities measured at fair value on recurring basis	$ (2,966)	$ (5,364)

Fair Value and Derivative Instruments - Additional Information (Details) $ in Thousands, € in Millions		3 Months Ended		9 Months Ended
	Oct. 09, 2019 EUR (€)	Sep. 26, 2020 USD ($)	Jun. 27, 2020 USD ($)	Sep. 26, 2020 USD ($)	Sep. 28, 2019 USD ($)	Dec. 28, 2019 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in amount of contingent consideration		$ (3,600)	$ 1,200	$ (3,771)	$ 0
Contingent consideration, liability		$ 2,966		2,966		$ 5,364
Business Combination Contingent Consideration Arrangements, Change In Amount Of Contingent Consideration Liability, Net				$ (2,400)
FRT
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent Consideration, Calculation Amount, Multiple of EBIT	150.00%
FRT \| Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration, liability \| €	€ 10.3

Fair Value and Derivative Instruments - Impact of Cash Flow Hedges and Derivatives (Details) - Designated as Hedging Instrument - Interest Rate Contracts - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)	$ (53)	$ 12	$ (323)	$ (78)
Reclassification out of Accumulated Other Comprehensive Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ (38)	$ 113	$ (26)	$ 496

Fair Value and Derivative Instruments - Foreign Currency Forward Contracts (Details) - 9 months ended Sep. 26, 2020 € in Thousands, ₩ in Thousands, ¥ in Thousands, $ in Thousands	USD ($)	EUR (€)	JPY (¥)	KRW (₩)
Derivative [Line Items]
Amount expected to be reclassified	$ 500
Foreign exchange forward contracts
Derivative [Line Items]
Derivative, notional amount	17,141
Buy \| Euro Dollar \| Foreign exchange forward contracts
Derivative [Line Items]
Derivative, notional amount	11,591	€ 10,341
Buy \| Korean Won \| Foreign exchange forward contracts
Derivative [Line Items]
Derivative, notional amount	2,785			₩ 3,259,002
Sell \| Euro Dollar \| Foreign exchange forward contracts
Derivative [Line Items]
Derivative, notional amount	11,447	€ 9,835
Sell \| Japanese Yen \| Foreign exchange forward contracts
Derivative [Line Items]
Derivative, notional amount	$ 20,070		¥ 2,119,658

Fair Value and Derivative Instruments - Gains and Losses Related to Non-designated Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Derivatives Not Designated as Hedging Instruments \| Foreign exchange forward contracts \| Location of Gain (Loss) Recognized on Derivatives
Derivatives, Fair Value [Line Items]
Derivatives Not Designated as Hedging Instruments	$ 529	$ (76)	$ 878	$ 198

Fair Value and Derivative Instruments - Assets Measured at Fair Value on a Non-Recurring Basis (Details) - USD ($)	Sep. 26, 2020	Dec. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on recurring basis	$ 3,237,000	$ 5,604,000
Assets measured at fair value on non-recurring basis	128,233,000	$ 93,450,000
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	$ 0

Fair Value and Derivative Instruments - Impact of Foreign Exchange Derivattive Contracts Designated as Cash Flow Hedges (Details) - Foreign exchange forward contracts - Designated as Hedging Instrument - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)				$ (1,096)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 236	$ (207)	$ 136	(448)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments and Tax	(553)	(642)	427
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	150	(126)	109	(297)
Research and development
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	23	(23)	11	(42)
Selling, general and administrative
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 63	$ (58)	$ 16	$ (109)

Warranty (Details) - USD ($) $ in Thousands	9 Months Ended
Warranty (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Sep. 28, 2019
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Balance at beginning of period	$ 1,942	$ 2,102
Accruals	2,771	2,742
Settlements	(2,838)	(3,051)
Balance at end of period	$ 1,875	$ 1,793

Property, Plant, and Equipment, net (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 346,131	$ 319,890
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(287,141)	(273,001)
Property Plant And Equipment Net, Excludes Construction in Progress	58,990	46,889
Construction in Progress, Gross	38,538	11,858
Property, plant and equipment, net of accumulated depreciation	97,528	58,747
Land
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	4,751	0
Equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	219,908	201,861
Computer Equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	36,050	35,192
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	7,022	6,756
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 78,400	$ 76,081

Stockholders’ Equity and Stock-Based Compensation - Additional Information (Details) - Equity Incentive Plan - USD ($) $ in Millions		9 Months Ended
	Aug. 27, 2020	Sep. 26, 2020
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)		1,189,018
PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	258,600
Grant date fair value	$ 6.9

Stockholders’ Equity and Stock-Based Compensation - Restricted Stock Unit Activity (Details) - Equity Incentive Plan - Restricted Stock Units	9 Months Ended
	Sep. 26, 2020 $ / shares shares
Units
Beginning balance (in shares) \| shares	3,069,000
Awards granted (in shares) \| shares	1,189,018
Awards vested (in shares) \| shares	(1,446,481)
Awards canceled (in shares) \| shares	(42,384)
Ending balance (in shares) \| shares	2,769,153
Weighted Average Grant Date Fair Value
Beginning Balance (in dollars per share) \| $ / shares	$ 14.30
Awards granted (in dollars per share) \| $ / shares	25.72
Awards vested (in dollars per share) \| $ / shares	13.70
Awards canceled (in dollars per share) \| $ / shares	14.64
Ending Balance (in dollars per share) \| $ / shares	$ 19.52

Stockholders’ Equity and Stock-Based Compensation - Stock Option Activity (Details) - Equity Incentive Plan $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 26, 2020 USD ($) $ / shares shares
Options Outstanding
Outstanding, beginning of period (In shares) \| shares	361,769
Options exercised (In shares) \| shares	(205,769)
Outstanding, end of period (In shares) \| shares	156,000
Exercisable (In shares) \| shares	156,000
Weighted Average Exercise Price
Outstanding, beginning of period (In dollars per share) \| $ / shares	$ 8.35
Options exercised (In dollars per share) \| $ / shares	8.32
Outstanding, end of period (In dollars per share) \| $ / shares	8.38
Exercisable (In dollars per share) \| $ / shares	$ 8.38
Additional Disclosures
Outstanding, weighted average remaining contractual life	1 year 4 months 20 days
Exercisable, weighted average remaining contractual life	1 year 4 months 20 days
Outstanding, aggregate intrinsic value \| $	$ 2,427,060
Exercisable, aggregate intrinsic value \| $	$ 2,427,060
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number \| shares	156,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price \| $ / shares	$ 8.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	1 year 4 months 20 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value \| $	$ 2,427,060

Stockholders’ Equity and Stock-Based Compensation - ESPP Activity (Details) - Employee stock purchase plan	9 Months Ended
	Sep. 26, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued under ESPP (In shares) \| shares	485,566
Weighted average per share purchase price (in dollars per share)	$ 16.47
Weighted average per share discount from the fair value of our common stock on the date of issuance (in dollars per share)	$ 11.00

Stockholders’ Equity and Stock-Based Compensation - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 5,509	$ 6,504	$ 16,774	$ 17,088
Cost of revenues
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	962	1,117	2,800	3,031
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	1,326	1,729	4,154	4,830
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 3,221	$ 3,658	$ 9,820	$ 9,227

Stockholders’ Equity and Stock-Based Compensation - Unrecognized Compensation Costs (Details) $ in Thousands	9 Months Ended
	Sep. 26, 2020 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock-based compensation expense	$ 46,005
Average expected recognition period	2 years 3 months 3 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized expense, other than options	$ 34,513
Average expected recognition period	2 years 3 months 21 days
Performance restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized expense, other than options	$ 10,499
Average expected recognition period	2 years 3 months 10 days
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized expense, other than options	$ 993
Average expected recognition period	4 months 6 days

Net Income per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
Net Income per Share (Details) - shares shares in Thousands	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Earnings Per Share [Abstract]
Weighted-average shares used in computing basic net income (loss) per share (In shares)	77,029	75,280	76,436	74,749
Add potentially dilutive securities (In shares)	1,780	2,011	2,098	2,014
Weighted-average shares used in computing diluted net income per share (In shares)	78,809	77,291	78,534	76,763
Anti-dilutive securities (In shares)	264	0	354	23

Leases - Narrative (Details)	Sep. 26, 2020
Lessee, Lease, Description [Line Items]
Operating lease, renewal term	20 years
Operating lease, weighted average remaining lease term	7 years
Operating lease, weighted average discount rate	4.52%
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	8 years
Automobiles \| Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	1 year
Automobiles \| Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	4 years

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Leases [Abstract]
Operating lease expense	$ 1,818	$ 1,726	$ 5,536	$ 5,205
Short-term lease expense	32	53	94	101
Variable lease expense	372	252	1,159	920
Lease, Cost	$ 2,222	$ 2,031	$ 6,789	$ 6,226

Leases - Schedule of Future Minimum Payments Under Leases (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Leases [Abstract]
Remainder of 2020	$ 1,877
2021	6,773
2022	5,549
2023	4,724
2024	4,471
Thereafter	16,272
Total minimum lease payments	39,666
Less: interest	(6,317)
Operating Lease, Liability, Total	33,349
Less: current portion	(6,555)	$ (6,551)
Long-term operating lease liabilities	$ 26,794	$ 29,088

Revenue (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended	12 Months Ended
Revenue (Details) - USD ($) $ in Millions	Dec. 26, 2020	Sep. 26, 2020	Dec. 25, 2022	Dec. 25, 2021	Dec. 28, 2019
Disaggregation of Revenue [Line Items]
Performance obligations		$ 3.8
Contract assets		3.5			$ 0.9
Contract liabilities		14.7			$ 10.8
Revenue recognized included in contracts		$ 8.6
Forecast
Disaggregation of Revenue [Line Items]
Expected to be recognized	31.90%		18.20%	49.90%

Operating Segments and Enterprise-Wide Information - Additional Information (Details)	9 Months Ended
	Sep. 26, 2020 segment
Segment Reporting [Abstract]
Number of reportable segments	2

Operating Segments and Enterprise-Wide Information - Operating Results by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Segment Reporting Information [Line Items]
Revenues	$ 177,996	$ 140,604	$ 496,573	$ 410,835
Gross profit	$ 76,749	$ 55,318	$ 210,306	$ 163,191
Gross margin	43.10%	39.30%	42.40%	39.70%
Probe Cards
Segment Reporting Information [Line Items]
Revenues	$ 150,773	$ 116,447	$ 419,272	$ 338,187
Systems
Segment Reporting Information [Line Items]
Revenues	27,223	24,157	77,301	72,648
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Gross profit	$ (6,457)	$ (5,824)	$ (19,219)	$ (17,425)
Gross margin	0.00%	0.00%	0.00%	0.00%
Operating Segments \| Probe Cards
Segment Reporting Information [Line Items]
Revenues	$ 150,773	$ 116,447	$ 419,272	$ 338,187
Gross profit	$ 69,641	$ 48,127	$ 191,907	$ 141,913
Gross margin	46.20%	41.30%	45.80%	42.00%
Operating Segments \| Systems
Segment Reporting Information [Line Items]
Revenues	$ 27,223	$ 24,157	$ 77,301	$ 72,648
Gross profit	$ 13,565	$ 13,015	$ 37,618	$ 38,703
Gross margin	49.80%	53.90%	48.70%	53.30%

- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8924-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

+ Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Operating Segments and Enterprise-Wide Information - Revenue by Segment, Recognition Type, and Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 177,996	$ 140,604	$ 496,573	$ 410,835
Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	150,773	116,447	419,272	338,187
Systems
Disaggregation of Revenue [Line Items]
Revenues	27,223	24,157	77,301	72,648
China
Disaggregation of Revenue [Line Items]
Revenues	28,546	31,383	120,946	73,581
China \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	24,851	24,427	107,756	58,882
China \| Systems
Disaggregation of Revenue [Line Items]
Revenues	3,695	6,956	13,190	14,699
Taiwan
Disaggregation of Revenue [Line Items]
Revenues	36,935	18,255	58,772	78,491
Taiwan \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	33,351	16,513	56,278	75,157
Taiwan \| Systems
Disaggregation of Revenue [Line Items]
Revenues	3,584	1,742	2,494	3,334
United States
Disaggregation of Revenue [Line Items]
Revenues	36,328	33,665	96,365	106,297
United States \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	31,596	28,400	79,575	88,127
United States \| Systems
Disaggregation of Revenue [Line Items]
Revenues	4,732	5,265	16,790	18,170
South Korea
Disaggregation of Revenue [Line Items]
Revenues	29,571	23,597	101,886	55,514
South Korea \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	28,337	22,779	93,596	50,596
South Korea \| Systems
Disaggregation of Revenue [Line Items]
Revenues	1,234	818	8,290	4,918
Europe
Disaggregation of Revenue [Line Items]
Revenues	16,979	9,548	52,154	29,689
Europe \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	11,679	5,754	36,656	15,601
Europe \| Systems
Disaggregation of Revenue [Line Items]
Revenues	5,300	3,794	15,498	14,088
Japan
Disaggregation of Revenue [Line Items]
Revenues	17,145	16,929	23,317	16,611
Japan \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	12,288	13,640	14,307	12,568
Japan \| Systems
Disaggregation of Revenue [Line Items]
Revenues	4,857	3,289	9,010	4,043
Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenues	8,954	5,665	35,574	43,454
Asia-Pacific \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	5,505	3,516	24,502	31,807
Asia-Pacific \| Systems
Disaggregation of Revenue [Line Items]
Revenues	3,449	2,149	11,072	11,647
Rest of the world
Disaggregation of Revenue [Line Items]
Revenues	3,538	1,562	7,559	7,198
Rest of the world \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	3,166	1,418	6,602	5,449
Rest of the world \| Systems
Disaggregation of Revenue [Line Items]
Revenues	372	144	957	1,749
Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenues	176,239	138,885	490,922	405,885
Products transferred at a point in time \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	150,252	115,324	417,529	335,054
Products transferred at a point in time \| Systems
Disaggregation of Revenue [Line Items]
Revenues	25,987	23,561	73,393	70,831
Services transferred over time
Disaggregation of Revenue [Line Items]
Revenues	1,757	1,719	5,651	4,950
Services transferred over time \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	521	1,123	1,743	3,133
Services transferred over time \| Systems
Disaggregation of Revenue [Line Items]
Revenues	1,236	596	3,908	1,817
Foundry & Logic
Disaggregation of Revenue [Line Items]
Revenues	108,411	68,431	323,503	213,453
Foundry & Logic \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	108,411	68,431	323,503	213,453
Foundry & Logic \| Systems
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
DRAM
Disaggregation of Revenue [Line Items]
Revenues	31,379	39,425	75,127	104,355
DRAM \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	31,379	39,425	75,127	104,355
DRAM \| Systems
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Flash
Disaggregation of Revenue [Line Items]
Revenues	10,983	8,591	20,642	20,379
Flash \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	10,983	8,591	20,642	20,379
Flash \| Systems
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Systems
Disaggregation of Revenue [Line Items]
Revenues	27,223	24,157	77,301	72,648
Systems \| Probe Cards
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Systems \| Systems
Disaggregation of Revenue [Line Items]
Revenues	$ 27,223	$ 24,157	$ 77,301	$ 72,648

Subsequent Event (Details) - Subsequent Event [Member] $ in Millions	Oct. 19, 2020 USD ($)
Subsequent Event [Line Items]
Consideration transferred	$ 17
Business Combination, Reason for Business Combination	This acquisition brings highly specialized skills and know-how to address the unique test challenges within the emerging quantum computing, superconducting computing, and ultra-sensitive sensor markets which operate at temperatures as low as 30 millikelvin.

Label	Element	Value
Common Stock [Member]
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	$ 1,000