STOCKHOLDERS' EQUITY (Tables)

3 Months Ended

Mar. 31, 2013

Stockholders' Equity Note [Abstract]

Summary of the distribution of stock-based compensation expense

The following table summarizes share-based compensation, net of amount capitalized in inventory, included in operating results for the three months ended March 31, 2013 and 2012:

	Three Months Ended
	March 31, 2013			March 31, 2012
	(In thousands)
Cost of revenue	$	1,844		$	2,255
Research and development	4,608			6,763
Selling, general and administrative	8,310			10,309
Total share-based compensation expense, before income taxes	14,762			19,327
Tax benefit	(2,606		)	(2,790		)
Total share-based compensation expense, net of income taxes	$	12,156		$	16,537

Activity under the entity's 2005 Stock Plan

Activity under Atmel’s 2005 Stock Plan is set forth below: 

			Outstanding Options			Weighted-
					Exercise	Average
	Available for Grant		Number of Options		Price per Share	Exercise Price per Share
	(In thousands, except per share data)
Balances, December 31, 2012	6,148		6,675		$1.68-$10.01	$	4.33
Restricted stock units issued	(1,182	)	—		—	—
Plan adjustment for restricted stock units issued	(721	)	—		—	—
Restricted stock units cancelled	319		—		—	—
Plan adjustment for restricted stock units cancelled	219		—		—	—
Performance-based restricted stock units cancelled	59		—		—	—
Plan adjustment for performance-based restricted stock units cancelled	36		—		—	—
Options cancelled/expired/forfeited	15		(15	)	$3.67-$7.12	4.97
Options exercised	—		(402	)	$1.68-$6.28	4.37
Balances, March 31, 2013	4,893		6,258		$1.77-$10.01	$	4.33

Activity related to restricted stock units

Activity related to restricted stock units is set forth below:

	Number of Units Outstanding		Weighted-Average Grant Date Fair Value
	(In thousands, except per share data)
Balances, December 31, 2012	21,944		$	8.71
Restricted stock units issued	1,182		6.85
Restricted stock units vested	(1,553	)	6.72
Restricted stock units cancelled	(319	)	8.32
Performance-based restricted stock units cancelled	(59	)	14.00
Balances, March 31, 2013	21,195		$	8.75

Assumptions used to estimate the fair value of the Company's ESPP shares

The following assumptions were utilized to determine the fair value of the 2010 ESPP shares:

	Three Months Ended
	March 31, 2013		March 31, 2012
Risk-free interest rate	0.13	%	0.15	%
Expected life (years)	0.50		0.50
Expected volatility	50	%	56	%
Expected dividend yield	—		—