Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

Stock-based compensation expense included in cost of goods sold and operating expenses for years ended December 31, 2012, 2011, and 2010 was as follows:

	Year Ended December 31,
	2012		2011		2010
Cost of goods sold	$	597	$	209	$	188
Operating expenses:
Research and development	1,336		753		362
Clinical and regulatory affairs	320		113		15
Marketing and sales	1,558		1,097		919
General and administrative	2,641		1,740		1,168
Total operating expenses	$	5,855	$	3,703	$	2,464
Total	$	6,452	$	3,912	$	2,652

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The fair value of stock options granted was estimated at the date of grant using the Black-Scholes option-pricing model. The following assumptions were used to determine fair value for the stock awards granted in the applicable year:

	Year Ended December 31,
	2012	2011	2010
Average expected option life (in years) (a)	6.0	6.0	6.0
Volatility (b)	55.8%	56.6%	56.4%
Risk-free interest rate (c)	1.0%	2.0%	2.4%
Dividend Yield (d)	—%	—%	—%
Weighted-average grant-date fair value per stock option	$6.90	$4.55	$2.46

(a) Determined by the historical stock option exercise behavior of the Company's employees (maximum term is 10

years).

(b) Measured using weekly price observations for a period equal to stock options' expected term.

(c) Based upon the U.S. Treasury yields in effect at the end of the quarter that the options were granted (for a period equaling the stock options' expected term).

(d) The Company has never paid cash dividends on its common stock and does not expect to declare any cash dividends.

Schedule of Share-based Compensation, Stock Options, Activity

Stock option activity during the years ended December 31, 2012, and 2011 is as follows:

	Number of Stock Options	Weighted Average Exercise Price	Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding — January 1, 2011	5,914,884	$3.91
Granted	1,264,333	8.38
Exercised	(1,393,794)	3.84		(a)	$7,246
Forfeited	(228,889)	5.29
Expired	—	—
Outstanding — December 31, 2011	5,556,534	$4.89
Granted	756,289	13.31
Exercised	(1,167,715)	4.28		(a)	$11,135
Forfeited	(188,378)	8.32
Expired	—	—
Outstanding — December 31, 2012	4,956,730	$6.21	6.9	(b)	$39,947
Vested and Expected to Vest — December 31, 2012	4,235,058	$5.87	6.7	(b)	$35,536
Vested — December 31, 2012	2,551,156	$4.35	5.7	(b)	$25,242

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range

The following table summarizes information regarding outstanding stock option grants as of December 31, 2012:

					Outstanding				Exercisable
Range of Exercise Prices					Granted Stock Options Outstanding	Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price		Granted Stock Options Exercisable	Weighted- Average Exercise Price
$	1.64	—	$	2.25	237,196	5.7	$	2.07	232,301	$	2.07
$	2.26	—	$	2.62	239,228	5.4	2.55		238,707	2.55
$	2.67	—	$	2.69	442,065	5.4	2.67		442,065	2.67
$	2.79	—	$	3.02	57,658	4.1	2.89		57,033	2.89
$	3.35	—	$	3.45	154,821	4.4	3.42		146,281	3.42
$	3.46	—	$	3.90	378,248	4.3	3.55		234,333	3.60
$	3.92	—	$	4.31	302,717	6.0	4.14		149,193	4.10
$	4.32	—	$	4.51	825,479	7.0	4.40		391,046	4.37
$	4.63	—	$	5.49	284,561	5.7	5.26		121,597	5.03
$	5.72	—	$	7.12	403,986	5.8	6.31		166,458	6.23
$	7.14	—	$	8.26	632,754	8.3	8.02		268,550	8.12
$	8.57	—	$	11.68	417,570	8.8	10.40		78,254	10.38
$	11.97	—	$	13.93	307,693	9.5	13.32		18,150	13.53
$	14.01	—	$	15.51	272,754	9.4	14.65		7,188	14.83
$	1.64	—	$	15.51	4,956,730	6.9	$	6.21	2,551,156	$	4.35

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

The following table summarizes activity and related information for the Company's restricted stock awards:

	Number of Restricted Stock Awards		Weighted Average Fair Value per Share at Grant Date		Grant Date Fair Value		Vest Date Fair Value*
Unvested as of December 31, 2009	685,000
Granted	518,045		$	5.95	$	3,082
Cancelled	(35,965	)
Vested	(575,625	)
Unvested as of December 31, 2010	591,455
Granted	34,000		$	6.19	$	210
Cancelled	(6,303	)
Vested	(35,851	)
Unvested as of December 31, 2011	583,301
Granted	475,253		$	12.67	$	6,022
Canceled	(43,598	)
Vested	(70,111	)					$	1,002
Unvested as of December 31, 2012	944,845