Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Income Statement [Abstract]
NET REVENUES	$ 250,112		$ 259,025		$ 297,366
COST OF REVENUES	117,185	[1]	115,881	[1]	128,535	[1]
GROSS PROFIT	132,927		143,144		168,831
OPERATING EXPENSES:
Research and development	57,182	[1]	49,952	[1]	46,271	[1]
Selling, general and administrative	48,010	[1]	46,415	[1]	47,590	[1]
Total operating expenses	105,192		96,367		93,861
INCOME FROM OPERATIONS	27,735		46,777		74,970
OTHER INCOME (EXPENSE):
Interest income	712		703		566
Interest expense			(19)		(223)
Other income (expense), net	(153)		141		149
Total other income, net	559		825		492
INCOME BEFORE INCOME TAXES AND NONCONTROLLING INTEREST	28,294		47,602		75,462
PROVISION FOR INCOME TAXES	15,966		13,742		24,927
NET INCOME	12,328		33,860		50,535
LESS: NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTEREST	(10)
NET INCOME ATTRIBUTABLE TO MICREL, INCORPORATED SHAREHOLDERS	$ 12,318		$ 33,860		$ 50,535
NET INCOME PER SHARE ATTRIBUTABLE TO MICREL, INCORPORATED SHAREHOLDERS:
Basic (dollars per share)	$ 0.21		$ 0.55		$ 0.81
Diluted (dollars per share)	$ 0.20		$ 0.54		$ 0.81
CASH DIVIDENDS DECLARED PER SHARE	$ 0.205	[2]	$ 0.15	[2]	$ 0.14	[2]
WEIGHTED AVERAGE SHARES USED IN COMPUTING PER SHARE AMOUNTS:
Basic (Shares)	59,623		61,609		62,030
Diluted (Shares)	60,288		62,371		62,557

[1] Share-based compensation expense included in Cost of revenues was $1,178 in 2012, $1,009 in 2011 and $798 in 2010; included in Research and development was $3,132 in 2012, $2,401 in 2011 and $1,808 in 2010; included in Selling, general and administrative was $3,282 in 2012, $2,444 in 2011 and $2,119 in 2010.

[2] Included an accelerated cash dividend of $0.0425 per share of common stock totaling $2.5 million paid on December 27, 2012 to shareholders of record as of December 18, 2012.