Share-Based Payments (Tables)

12 Months Ended

Dec. 31, 2013

Share-Based Payments

Schedule of share-based compensation recognized related to the grant of employee and non-employee stock options, SARS and non-vested stock

	Year Ended December 31,
	2013		2012		2011
	(in thousands)
Research and development	$	417	$	208	$	63
Selling, general and administrative		1,291		131		(145	)
Total	$	1,708	$	339	$	(82	)

Schedule of assumptions used in estimation of fair value of each award option on the date of grant using Black-Scholes option-pricing model

	Year Ended December 31,
	2013	2012	2011
Fair value of common stock	$5.40 - $7.90	$5.07 - $12.92	$2.56 - $3.36
Expected volatility	69.5% - 70.9%	68.3% - 71.6%	59.1% - 74.7%
Dividend Yield	0%	0%	0%
Expected term	6.25 - 9.60 years	6.25 years	0.41 - 6.25 years
Risk-free interest rate	1.20% - 2.94%	0.89% - 1.14%	0.15% - 2.93%
Expected forfeiture rate	5%	0% - 5%	0% - 5%

Summary of stock option and SAR activity

	Number of Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term
Outstanding, December 31, 2011		598,109		$	2.75		7.71
Granted		188,136		$	10.73
Exercised		(159,264	)	$	1.67
Forfeited or expired		(57,070	)	$	2.45
Outstanding, December 31, 2012		569,911		$	5.72		7.88
Granted		974,582		$	7.79
Exercised		(62,513	)	$	1.25
Forfeited or expired		(18,937	)	$	6.47
Outstanding, December 31, 2013		1,463,043		$	7.27		8.51
As of December 31, 2013:
Vested and expected to vest		1,425,752		$	7.26		8.50
Exercisable		256,227		$	4.47		6.44