Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2012

Stock-Based Compensation [Abstract]

Assumption of stock option's fair value

	Three Months Ended						Six Months Ended
	June 30, 2012			July 2, 2011			June 30, 2012			July 2, 2011
Stock Options
Expected life		4.2 years			4.5 years			4.5 years			4.5 years
Volatility		78.65	%		77.49	%		78.23	%		76.97	%
Risk free interest rate		0.74	%		1.84	%		0.85	%		2.00	%
Dividends		0			0			0			0
Employee Stock Purchase Plan
Expected life		0.5 years			0.5 years			0.5 years			0.5 years
Volatility		55.93	%		68.27	%		62.74	%		76.20	%
Risk free interest rate		0.06	%		0.21	%		0.06	%		0.20	%
Dividends		0			0			0			0

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		(281,450	)		6.32
Granted		200,485			17.72
Cancelled		(49,843	)		14.53
Outstanding at June 30, 2012		2,217,354		$	11.62		4.69	$	9,587
Exercisable at June 30, 2012		1,206,793		$	9.14		4.00	$	7,781

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

	Three Months Ended				Six Months Ended
	June 30, 2012		July 2, 2011		June 30, 2012		July 2, 2011
Cost of products	$	20	$	28	$	77	$	66
Cost of service		75		43		133		95
Research and development		347		221		666		368
Selling		481		311		922		526
General and administrative		670		352		1,256		722
Total stock-based compensation expense	$	1,593	$	955	$	3,054	$	1,777