Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2012

Stock-based Compensation [Abstract]

Allocation Of Stock-Based Compensation To Expense Catagories

	Three Months Ended September 30, (unaudited)				Nine Months Ended September 30, (unaudited)
	2012		2011		2012		2011
Cost of revenue	$	70	$	62	$	206	$	148
Research and development		147		130		434		279
Selling, general and administrative		342		224		1,319		1,350
Total stock compensation expense	$	559	$	416	$	1,959	$	1,777

Key Assumptions Used For Black-Scholes Option Pricing Model

	For the Nine Months Ended September 30,
	2012			2011
Dividend yield		0	%		0	%
Risk free interest rates		0.36 – 0.87	%		1.04 - 2.37	%
Expected  volatility		71.8 to 81.2	%		67.1 to 85.7	%
Expected term (in years)		3.0 to 5.5			3.5 to 5.5

Stock Option Activity

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (In Years)		Aggregate Intrinsic Value
Outstanding at December 31, 2011		4,242,251		$	3.93
Options granted		687,531			3.47
Options exercised		(160,563	)		1.59
Options forfeited or expired		(18,152	)		8.83
Options cancelled		—			—
Outstanding at September 30, 2012		4,751,067		$	3.93		5.53	$	5,725,866
Vested or expected to vest at September 30, 2012 (1)		4,674,855		$	3.90		5.55	$	5,700,655
Exercisable at September 30, 2012		3,226,827		$	3.14		5.92	$	5,221,647

(1) The expected to vest options are the result of applying the pre-vesting forfeiture rate assumptions to total unvested options.