Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Accounting Policies [Abstract]

Schedule of Quantifying Prior Year Misstatements Corrected in Current Year Financial Statements

Following are the line items within the consolidated financial statements for and as of the years ended December 31, 2011 and 2010 that have been impacted by the revisions.  

	As of December 31, 2011							As of December 31, 2010
(in thousands)	As Reported		Adjustment			As Revised		As Reported		Adjustment			As Revised
Consolidated Balance Sheets
Income taxes receivable	$	6,881	$	(44	)	$	6,837	$	6,547	$	154		$	6,701
Short-term deferred income taxes	22,854		348			23,202		25,022		88			25,110
Total current assets	232,164		304			232,468		214,362		242			214,604
Long-term deferred income taxes	8,657		(2,261		)	6,396		9,740		(2,001		)	7,739
Total assets	309,975		(1,957		)	308,018		302,453		(1,759		)	300,694
Long-term income taxes payable	6,450		(46		)	6,404		5,664		(4		)	5,660
Total liabilities	63,546		(46		)	63,500		78,812		(4		)	78,808
Retained earnings	247,110		(1,911		)	245,199		222,452		(1,755		)	220,697
Total shareholders’ equity	246,429		(1,911		)	244,518		223,641		(1,755		)	221,886
Total liabilities and shareholders’ equity	309,975		(1,957		)	308,018		302,453		(1,759		)	300,694

	For the  Year Ended December 31, 2011							For the  Year Ended December 31, 2010
(in thousands except per share amounts)	As Reported		Adjustment			As Revised		As Reported		Adjustment			As Revised
Consolidated Statements of Operations
Provision for income taxes	$	13,586	$	156		$	13,742	$	24,754	$	173		$	24,927
Net income	34,016		(156		)	33,860		50,708		(173		)	50,535
Net income per share:
Basic	0.55		—			0.55		0.82		(0.01		)	0.81
Diluted	0.55		(0.01		)	0.54		0.81		—			0.81

	For the  Year Ended December 31, 2011							For the  Year Ended December 31, 2010
(in thousands)	As Reported		Adjustment			As Revised		As Reported		Adjustment			As Revised
Consolidated Statements of Other Comprehensive Income
Net income	$	34,016	$	(156	)	$	33,860	$	50,708	$	(173	)	$	50,535
Comprehensive income	34,341		(156		)	34,185		51,255		(173		)	51,082

	As of and for the  Year Ended December 31, 2011							As of and for the  Year Ended December 31, 2010
(in thousands)	As Reported		Adjustment			As Revised		As Reported		Adjustment			As Revised
Consolidated Statements of Shareholders' Equity
Net income	$	34,016	$	(156	)	$	33,860	$	50,708	$	(173	)	$	50,535
Retained earnings	247,110		(1,911		)	245,199		222,452		(1,755		)	220,697
Total shareholders’ equity	246,429		(1,911		)	244,518		223,641		(1,755		)	221,886

Available-for-sale Securities

A summary of the Company’s short-term investments at December 31, 2012 and 2011 was as follows (in thousands):

	As of December 31, 2012									As of December 31, 2011
	Cost		Gross Gains		Gross Losses			Fair Value		Cost		Gross Gains		Gross Losses			Fair Value
Municipal Securities	$	12,520	$	—	$	(116	)	$	12,404	$	11,413	$	—	$	(115	)	$	11,298
Corporate Debt Securities	26,575		—		(139		)	26,436		33,723		—		(327		)	33,396
Commercial Paper	18,464		—		(2		)	18,462		4,991		—		(2		)	4,989
U.S. Agencies	—		—		—			—		4,528		—		(17		)	4,511
Certificates of Deposits	19,047		—		—			19,047		23,071		—		—			23,071
Total	$	76,606	$	—	$	(257	)	$	76,349	$	77,726	$	—	$	(461	)	$	77,265

Fair Value, Assets Measured on Recurring Basis

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

	Fair Value Measurements as of December 31, 2012
	Quoted Prices in Active Markets for Identical Assets Level 1		Significant Other Observable Inputs Level 2		Significant Unobservable Inputs Level 3		Total
Money Market Funds (1)	$	13,845	$	—	$	—	$	13,845
Certificates of Deposits (2)	19,046		—		—		19,046
Corporate Debt Securities (2)	—		26,437		—		26,437
Commercial Paper (2)	—		18,462		—		18,462
Municipal Securities (2)	—		12,404		—		12,404
U.S. Agencies (2)	—		—		—		—
Auction rate notes (3)	—		—		4,159		4,159
Total	$	32,891	$	57,303	$	4,159	$	94,353

	Fair Value Measurements as of December 31, 2011
	Quoted Prices in Active Markets for Identical Assets Level 1		Significant Other Observable Inputs Level 2		Significant Unobservable Inputs Level 3		Total
Money Market Funds (1)	$	55,912	$	—	$	—	$	55,912
Certificates of Deposits (2)	23,071		—		—		23,071
Corporate Debt Securities (2)	—		33,396		—		33,396
Commercial Paper (2)	—		4,989		—		4,989
Municipal Securities (2)	—		11,298		—		11,298
U.S. Agencies (2)	—		4,511		—		4,511
Auction rate notes (3)	—		—		6,857		6,857
Total	$	78,983	$	54,194	$	6,857	$	140,034

__________

(1) Included in cash and cash equivalents

(2) Included in short-term investments

(3) Included in long-term investments

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure

For the year ended December 31, 2012, the changes in the Company’s Level 3 securities (consisting of auction rate notes) were as follows (in thousands):

	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Beginning balance, December 31, 2011	$	6,857
Transfers in and/or out of Level 3	—
Total gains, before tax, included in other comprehensive income	402
Settlements	(3,100		)
Ending balance, December 31, 2012	$	4,159

Reconciliation of weighted-average shares used in computing net income per share

Reconciliation of weighted-average shares used in computing net income per share attributable to Micrel, Incorporated shareholders is as follows (in thousands):

	Year Ended December 31,
	2012	2011	2010
Weighted average common shares outstanding	59,623	61,609	62,030
Dilutive effect of stock options and restricted stock units	665	762	527
Shares used in computing diluted net income per share	60,288	62,371	62,557