Note 3 - Revenue From Contracts With Customers - Contract Balance (Details) $ in Thousands	9 Months Ended
Sep. 26, 2020 USD ($)
Contract assets, balance	$ 5,569
Revenues recorded during the period	11,660
Transferred to Accounts receivable or collected	(12,091)
Contract assets, balance	5,138
Contract liabilities	2,313
Accruals for estimated future stock rotation and scrap returns	4,474
Less: Release of accruals for recognized stock rotation and scrap returns	(2,571)
Prepayment for performance obligations expected to be satisfied within three months	336
Less: Revenue recognized on satisfaction of performance obligations	(179)
Contract liabilities	$ 4,373

No definition available.

Name:	lscc_ContractWithCustomerAssetRevenueRecordedDuringPeriod
Namespace Prefix:	lscc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents accrued for estimated future stock rotation and scrap returns for contract with customer liability.

+ References

No definition available.

+ Details

Name:	lscc_ContractWithCustomerLiabilityAccruedForEstimatedFutureStockRotationAndScrapReturns
Namespace Prefix:	lscc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of increase in contract with customer liability during the period due to prepayment for performance obligations expected to be satisfied within three months.

+ References

No definition available.

+ Details

Name:	lscc_ContractWithCustomerLiabilityPrepaymentForPerformanceObligationsExpectedToBeSatisfiedWithinThreeMonths
Namespace Prefix:	lscc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents release of accruals for recognized stock rotation and scrap returns for contract with customer liabilities.

+ References

No definition available.

+ Details

Name:	lscc_ContractWithCustomerLiabilityReleaseOfAccrualsForRecognizedStockRotationAndScrapReturns
Namespace Prefix:	lscc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130549-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130531-203044

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130533-203044

+ Details

Name:	us-gaap_ContractWithCustomerAssetNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time from transfer to receivable due to right to consideration becoming unconditional.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130551-203045

+ Details

Name:	us-gaap_ContractWithCustomerAssetReclassifiedToReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130549-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121556615&loc=SL49130532-203044

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

+ Details

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration