Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2012

Stockholders' equity [Abstract]

Restricted stock unit activity

	Number of Units			Weighted Average Grant-Date Fair Value		Aggregate Intrinsic Value
Balance at December 31, 2011		1,096		$	4.76
Granted		625,148			5.28
Vested		—			—
Forfeited		(11,500	)		5.29
Balance at June 30, 2012		614,744			5.28		3,221,259

Summary of stock options activity

	Number of options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
Balance at December 31, 2011		7,576,493		$	5.75
Granted		—			—
Exercised		(247,501	)		1.60
Expired/terminated		(320,786	)		7.57
Balance at June 30, 2012		7,008,206		$	5.81		5.35	$	4,343,755
Exercisable at June 30, 2012		6,339,175		$	6.01		4.77	$	3,634,350
Expected to vest after June 30, 2012		628,889		$	4.72		7.85	$	709,405

Weighted-average fair value per share of options granted

	Three Months Ended June  30,			Six Months Ended June 30,
	2011			2011
Expected life of options		4.5 yea	rs		4.5 yea	rs
Weighted average volatility		52.8	%		55.7	%
Weighted average risk-free interest rate		1.5	%		1.7	%
Weighted average fair value of options granted	$	2.01		$	2.17

Reported share-based compensation

	Three Months Ended June 30 ,				Six Months Ended June 30,
	2012		2011		2012		2011
Cost of products sold	$	28,748	$	51,976	$	95,892	$	104,980
Sales, general and administrative expenses		426,314		649,566		973,364		1,372,745
Research and development expenses		134,629		175,465		278,406		362,199
Total stock-based compensation	$	589,691	$	877,007	$	1,347,662	$	1,839,924

Repurchases of common stock

	Total Number of Shares Purchased		Average Price Paid per Share		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs		Approximate Dollar Value of Shares that May Yet be Purchased  Under the Plans or Programs
April 1-30, 2012		—	$	—		—	$	—
May 1-31, 2012		2,579,406		5.13		2,579,406		6,694,360
June 1-30, 2012		534,400		5.27		534,400		3,861,449
Total		3,113,806	$	5.18		3,113,806	$	3,861,449