Stockholders' Equity (Tables)

9 Months Ended

Sep. 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		637,148			5.29
Vested		—			—
Forfeited		(19,025	)		4.79
Balance at September 30, 2012		619,219			5.29	$	3,740,083

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		(443,136	)		4.71
Expired/terminated		(370,285	)		7.91
Balance at September 30, 2012		6,763,072			5.92		5.19		6,778,568
Exercisable at September 30, 2012		5,591,287			6.17		4.69		5,258,785
Expected to vest after September 30, 2012		818,240			4.64		7.76		1,139,383

Weighted-average fair value per share of options granted

	Three Months Ended Sept 30,			Nine Months Ended Sept 30,
	2011			2011
Expected life of options		4.5 years			4.5 years
Weighted average volatility		54.4	%		55.6	%
Weighted average risk-free interest rate		0.9	%		1.7	%
Weighted average fair value of options granted	$	1.97		$	2.16

Reported share-based compensation

	Three Months Ended September 30,				Nine Months Ended Sept 30,
	2012		2011		2012		2011
Cost of products sold	$	38,085	$	30,238	$	133,977	$	135,217
Sales, general and administrative expenses		657,870		518,513		1,631,234		1,891,258
Research and development expenses		153,433		144,769		431,839		506,969
Total share-based compensation	$	849,388	$	693,520	$	2,197,050	$	2,533,444