Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2012

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Fair Value of Stock Options and Performance Stock Awards

The following table presents the weighted average assumptions used by the Company to estimate the fair value of stock options and performance stock awards granted under the Company’s equity incentive plans and the shares purchasable under the Company’s ESPP, as well as the resulting average fair values:

	Three Months Ended March 31,
	2012			2011
Stock options
Risk-free interest rate	0.7		%	1.7		%
Volatility	34.5		%	31.0		%
Dividend yield	—			—
Expected term (years)	4.3			4.3
Resulting average fair value	$	19.57		$	17.46
Performance stock awards
Risk-free interest rate	0.4		%	1.3		%
Volatility	30.1		%	33.4		%
Dividend yield	—			—
Resulting average fair value	$	81.96		$	82.58
Employee stock purchase plan shares
Risk-free interest rate	0.1		%	0.2		%
Volatility	38.7		%	21.5		%
Dividend yield	—			—
Expected term (years)	0.5			0.5
Resulting average fair value	$	15.27		$	12.27

Schedule of Unrecognized Stock-based Compensation Expense Before Income Taxes and Adjusted for Estimated Forfeitures

The Company’s unrecognized stock-based compensation expense as of March 31, 2012, before income taxes and adjusted for estimated forfeitures, related to outstanding unvested share-based payment awards was as follows (in thousands, except number of years):

	Weighted Average Remaining Expense Life (Years)	Unrecognized Expense
Stock options	3.0	$	36,530
Performance stock awards	2.6	10,871
Restricted stock	1.8	1,907
Deferred issuance restricted stock	1.2	247
Employee stock purchase plan shares	0.2	118
Total		$	49,673

Schedule of Stock-based Compensation Expense

The following table summarizes the stock-based compensation expense that the Company recorded in its consolidated statements of income for the three month periods ended March 31, 2012 and 2011 (in thousands):

	Three Months Ended March 31,
	2012		2011
Cost of product sales	$	850	$	788
Research and development	1,724		1,792
Marketing and sales	731		612
General and administrative	2,847		2,844
Total	$	6,152	$	6,036

Schedule of Computation of Basic and Diluted Earnings per Share

The following table sets forth the computation of basic and diluted EPS for the three month periods ended March 31, 2012 and 2011 (in thousands, except per share amounts):

	Three Months Ended March 31,
	2012			2011
Basic net income per share
Net income	$	22,460		$	23,277
Less income allocated to participating securities	(30		)	(35		)
Net income allocated to common stockholders	$	22,430		$	23,242
Weighted average common shares outstanding - basic	45,124			47,861
Net income per share - basic	$	0.50		$	0.49

	Three Months Ended March 31,
	2012			2011
Diluted net income per share
Net income	$	22,460		$	23,277
Less income allocated to participating securities	(29		)	—
Net income allocated to common stockholders	$	22,431		$	23,277
Weighted average common shares outstanding - basic	45,124			47,861
Dilutive securities	1,080			1,143
Weighted average common shares outstanding - diluted	46,204			49,004
Net income per share - diluted	$	0.49		$	0.48