Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2013

Stockholders' Equity [Abstract]

Summary of restricted stock unit activity

	Number of Units			Weighted Average  Grant- Date Fair Value		Aggregate Intrinsic Value
Units outstanding, beginning of period		582,212		$	5.42
Granted		576,376			8.92
Released		(123,501	)		5.28
Forfeited		(14,126	)		5.30
Units outstanding, end of period		1,020,961			7.41	$	8,116,640

Summary of the Company's stock options

	Number of options			Weighted Average Exercise Price		Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
Options outstanding, beginning of period		6,321,076		$	6.05
Granted		—			—
Exercised		(242,678	)		1.25
Expired / forfeited		(24,027	)		4.81
Options outstanding, end of period		6,054,371			6.25		4.88	$	12,835,996
Exercisable at March 31, 2013		5,218,671			6.49		4.53		10,133,307
Expected to vest after March 31, 2013		642,255			4.58		6.70		2,162,786

Reported share-based compensation

	Three Months Ended March 31,
	2013		2012
Cost of products sold	$	34,432	$	67,144
Sales, general and administrative expenses		730,504		547,133
Research and development expenses		158,405		143,777
Total share-based compensation	$	923,341	$	758,054