Stock-Based Compensation (Tables)

9 Months Ended

Sep. 29, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Assumption of stock option's fair value

	Three Months Ended				Nine Months Ended
	September 29, 2012		October 1, 2011		September 29, 2012		October 1, 2011
Stock Options
Expected life	4.6 years		4.6 years		4.5 years		4.5 years
Volatility	75.44	%	77.47	%	77.96	%	77.02	%
Risk free interest rate	0.74	%	1.01	%	0.84	%	1.89	%
Dividends	—		—		—		—
Employee Stock Purchase Plan
Expected life	0.5 years		0.5 years		0.5 years		0.5 years
Volatility	38.58	%	65.91	%	45.47	%	73.41	%
Risk free interest rate	0.16	%	0.17	%	0.12	%	0.19	%
Dividends	—		—		—		—

Stock option plans activity

	Number of Shares Outstanding (Options)		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in Thousands)
Options
Outstanding at December 31, 2011	2,348,162		$	10.53	4.86	$	18,556
Exercised	(403,397	)	6.47
Granted	221,785		17.48
Cancelled	(112,087	)	14.72
Outstanding at September 29, 2012	2,054,463		$	11.85	4.53	$	6,642
Exercisable at September 29, 2012	1,206,804		$	9.68	3.83	$	5,811

Stock-based compensation expense for all share-based payment awards

	Three Months Ended				Nine Months Ended
	September 29, 2012		October 1, 2011		September 29, 2012		October 1, 2011
Cost of products	$	50	$	45	$	128	$	111
Cost of service	62		51		195		146
Research and development	289		221		952		589
Selling	451		264		1,374		790
General and administrative	630		389		1,886		1,110
Total stock-based compensation expense	$	1,482	$	970	$	4,535	$	2,746