Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule Of Share-Based Compensation Expense Included In Statements Of Operations

	Year ended December 31,
	2013		2012		2011
Research and development expense	$	1,594,603	$	765,126	$	706,734
Sales and marketing expense		327,199		207,125		121,384
General and administrative expense		5,009,636		2,581,163		609,056
Total share-based expense	$	6,931,438	$	3,553,414	$	1,437,174

Summary Of Options And Warrants By Exercise Price Range

	Options and Warrants Outstanding				Options and Warrants Exercisable
Range of Exercise Prices	Number Outstanding at December 31,  2013	Wtd. Avg. Exercise Price		Wtd. Avg. Remaining Contractual Life	Number Exercisable at December 31, 2013	Wtd. Avg. Exercise Price		Wtd. Avg. Remaining Contractual Life
$0.54 - $0.88	1,960,208	$	0.59	2.29	1,925,030	$	0.59	2.25
$0.89 - $1.88	2,708,742	$	1.00	4.54	1,771,182	$	1.01	4.35
$2.01 - $3.13	3,019,371	$	2.81	5.21	1,972,987	$	2.84	5.00
$3.15 - $5.40	404,655	$	4.30	2.98	274,624	$	4.35	1.14
$5.70 - $8.60	337,470	$	6.74	1.10	337,470	$	6.74	1.10
$9.06 - $26.75	458,281	$	11.08	0.58	458,281	$	11.08	0.58
	8,888,727	$	2.41	3.87	6,739,574	$	2.53	3.39

Stock Options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary Of Options Activity

	Shares	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value ($)
Outstanding at beginning of year	7,514,697	$	3.26
Granted	258,780		3.32
Exercised	(217,181)		1.21
Forfeited	0		0
Expired	(627,086)		8.36
Outstanding at end of year	6,929,210		2.87	4.40	years	$	15,433,876
Exercisable at end of year	4,780,057	$	3.24	3.98	years	$	10,042,794

Summary Of Valuation Assumptions

	Year ended December 31,
	2013	2012	2011
Expected option term 1	5 to 6 years	6 to 7 years	5 to 6 years
Expected volatility factor 2	97.9% to 103.7%	90.2% to 94.8%	92.0% to 97.7%
Risk-free interest rate 3	0.8% to 1.8%	0.8% to 1.0%	0.9% to 2.0%
Expected annual dividend yield	0%	0%	0%

1The expected term was generally determined based on historical activity for grants with similar terms and for similar groups of employees and represents the period of time that options are expected to be outstanding.  For employee options, groups of employees with similar historical exercise behavior are considered separately for valuation purposes.   For consultants, the expected term was determined based on the contractual life of the award.

2The stock volatility for each grant is measured using the weighted average of historical daily price changes of our common stock over the most recent period equal to the expected option life of the grant.  

3The risk-free interest rate for periods equal to the expected term of the share option is based on the U.S. Treasury yield curve in effect at the measurement date. 

Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary Of Restricted Stock Activity

	Non-vested Shares
	Shares	Weighted-Average Grant-Date Fair Value
Non-vested at beginning of year	480,000	$	0.99
Granted	900,000		3.90
Vested	(496,666)		1.09
Forfeited	0		0
Non-vested at end of year	883,334	$	3.90

Warrant [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary Of Non-Plan Options And Warrants

	Shares	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term		Aggregate Intrinsic Value ($)
Outstanding at beginning of year	2,967,911	$	0.87
Granted	0		0
Exercised	(1,008,394)		0.99
Forfeited	0		0
Expired	0		0
Outstanding at end of year	1,959,517		0.81	1.96	years	$	7,336,710
Exercisable at end of year	1,959,517	$	0.81	1.96	years	$	7,336,710

Summary Of Valuation Assumptions

	Year ended December 31,
	2013	2012	2011
Expected option term 1	4 to 5 years	4 to 6 years	4 to 5 years
Expected volatility factor 2	91.5% to 104%	93.4% to 104.3%	89.4% to 100.2%
Risk-free interest rate 3	0.5% to 1.0%	0.7% to 1.0%	0.9% to 2.4%
Expected annual dividend yield	0%	0%	0%

1The expected term was determined based on the remaining contractual life of the award on the measurement date.

2The stock volatility for each grant is measured using the weighted average of historical daily price changes of our common stock over the most recent period equal to the expected life of the award.  

3The risk-free interest rate for periods equal to the expected term of the award is based on the U.S. Treasury yield curve in effect at the measurement date. 

Restricted Stock Award And Restricted Stock Unit [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary Of Restricted Stock Activity

	Non-vested Shares
	Shares	Weighted-Average Grant-Date Fair Value
Non-vested at beginning of year	953,842	$	2.67
Granted	259,290		3.99
Vested	(214,082)		3.22
Forfeited	0		0
Non-vested at end of year	999,050	$	2.90