Significant Accounting Policies (Policies)	9 Months Ended
Significant Accounting Policies (Policies)	Sep. 30, 2013
Accounting Policies [Abstract]
Interim Financial Information	Interim Financial Information - The accompanying condensed consolidated financial statements of Micrel, Incorporated and its wholly-owned subsidiaries (together “Micrel” or the “Company”) as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 are unaudited. In the opinion of management, the condensed consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) that management considers necessary for a fair statement of its financial position, operating results, comprehensive income and cash flows for the interim periods presented. Operating results and cash flows for interim periods are not necessarily indicative of results for the entire year. The Condensed Consolidated Balance Sheet as of December 31, 2012, was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted (“GAAP”) in the United States of America. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012. These financial statements should also be read in conjunction with the Company’s critical accounting policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012 and those included in this Form 10-Q below.
Net Income Per Common and Equivalent Share	For the three and nine months ended September 30, 2013, 5.4 million and 5.3 million shares underlying stock options, respectively, have been excluded from the weighted-average number of common shares outstanding for the diluted net income per share computations as they were anti-dilutive. For the three and nine months September 30, 2012, 5.7 million and 5.5 million shares underlying stock options, respectively, have been excluded from the weighted-average number of common shares outstanding for the diluted net income per share computations as they were anti-dilutive.
New Accounting Pronouncements	Effective January 1, 2013, the Company adopted the new guidance to improve the reporting of reclassifications out of accumulated other comprehensive income. The guidance requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required under GAAP to be reclassified in its entirety to net income. For other amounts that are not required under GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under GAAP that provide addition detail about those amounts. The adoption did not have a material impact on the Company's consolidated financial condition or results of operations. Effective January 1, 2013, the Company adopted the new guidance to reduce the complexity and cost of performing an evaluation of impairment of indefinite-lived intangible assets other than goodwill. Under the new guidance, an entity is permitted to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test. The adoption did not have a material impact on the Company's consolidated financial condition or results of operations. In March 2013, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on foreign currency matters that provides additional guidance with respect to the reclassification into income of the cumulative translation adjustment (CTA) recorded in accumulated other comprehensive income associated with a parent company's ownership interest in a foreign entity. The standard differentiates between transactions occurring within a foreign entity and transactions/events affecting an investment in a foreign entity. For transactions within a foreign entity, the full CTA associated with the foreign entity would be reclassified into income only when the sale of a subsidiary or group of net assets within the foreign entity represents the substantially complete liquidation of that foreign entity. For transactions/events affecting an investment in a foreign entity (for example, control or ownership of shares in a foreign entity), the full CTA associated with the foreign entity would be reclassified into income only if the parent no longer has a controlling interest in that foreign entity as a result of the transaction/event. In addition, acquisitions of a foreign entity completed in stages will trigger release of the CTA associated with an equity method investment in that entity at the point a controlling interest in the foreign entity is obtained. The Company is required to adopt this standard for its interim and annual periods beginning after December 15, 2013. As of September 30, 2013, the Company has not recorded a CTA related to its ownership interests in a foreign entity. This standard would impact the Company's consolidated financial condition or results of operations only in the instance the Company records a CTA and an event or transaction described above occurs. In July 2013, the FASB issued an accounting standards update on presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward (each, a “Carryforward”) exists. The standard requires that unrecognized tax benefits should be presented as a reduction to deferred tax assets for a Carryforward, if such Carryforward is required or expected to settle the additional income taxes in the event the uncertain tax position is disallowed. The standard also requires in situations that a Carryforward cannot be used or the deferred tax asset is not intended to be used for such purpose, the unrecognized tax benefit should be recorded as a liability and should not offset deferred tax assets. The Company is required to adopt this standard for its interim and annual periods beginning after December 15, 2013. The Company is currently evaluating the impact of adopting this guidance, but does not expect it to have a material impact on the Company's consolidated financial condition or results of operations.

Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.

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