Impairment of Goodwill and Intangible Assets	12 Months Ended
Impairment of Goodwill and Intangible Assets	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of Goodwill and Intangible Assets	Impairment of Goodwill and Intangible Assets In connection with our acquisitions of Silicon Image in March 2015 and SiliconBlue in December 2011 we recorded goodwill and identifiable intangible assets related to developed technology, customer relationships, licensed technology, patents, and in-process research. We monitor the carrying value of our goodwill and intangible assets for potential impairment and test the recoverability of such assets annually during the fourth quarter and whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. In September 2016, the Founders of the HDMI consortium, of which we are a member, amended the existing Founders Agreement resulting in changes to our role as agent for the HDMI consortium and to the model for sharing adopter fee revenues. Lattice historically served the role of the HDMI licensing agent via a wholly owned subsidiary, HDMI Licensing LLC. Under the terms of the new agreement, our role as the agent was terminated effective January 1, 2017 and a new independent entity was appointed to act as the new HDMI licensing agent with responsibility for licensing and the distribution of royalties among Founders. As a result of the amended model for sharing revenue, we will be entitled to a reduced share of adopter fees paid by parties adopting the HDMI standard. We determined that this modification constituted an impairment indicator related to the intangible assets associated with future HDMI adopter fees. Our assessment of the new value of these intangible assets concluded that they had been impaired as of the end of the third quarter of fiscal 2016, and we recorded a $7.9 million non-cash impairment charge in the Consolidated Statements of Operations. We do not anticipate any future cash expenditures related to this impairment. No impairment charges related to goodwill were recorded in fiscal 2016 as no indicators of impairment were present. For fiscal 2015, the impairment of goodwill and intangible assets was related to Qterics, Inc., which was acquired in the March 2015 acquisition of Silicon Image. During the fourth quarter of fiscal 2015, we determined that we experienced an impairment indicator related to the long-lived assets of the Qterics operating segment. For purposes of testing for impairment in fiscal 2015, the Company operated as two reporting units: the continuing core Lattice ("Core") business, which includes intellectual property and semiconductor devices, and Qterics, which was a discrete software-as-a-service business unit in the Lattice legal entity structure until it was sold in April 2016. Although these two operating segments constituted two reportable segments in fiscal 2015, we combined Qterics with our Core business and reported them together as one reportable segment due to the immaterial nature of the Qterics segment. Following this assessment, we concluded that goodwill and intangible assets had been impaired in the Qterics segment as of January 2, 2016. As a result we recorded an impairment charge amounting to $21.7 million, or approximately 92% of the previous value of goodwill and intangible assets, in the Consolidated Statements of Operations for the year ended January 2, 2016, comprising $12.7 million pertaining to goodwill, $3.9 million pertaining to developed technology, and $5.1 million pertaining to customer relationships. The valuation was based on the market approach and was our best estimate of fair value as of the end of fiscal 2015. No impairment charges were recorded for the Core segment in fiscal 2015, and we had no impairment charges in fiscal 2014

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.