Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2011

Summary of Significant Accounting Policies (Tables) [Abstract]

Fair value of stock options, performance stock awards and shares purchasable under ESPP

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2011			2010			2011			2010
Stock option plans
Risk-free interest rate		1.9	%		2.1	%		1.7	%		2.1	%
Volatility		30.2	%		31.4	%		30.9	%		32.1	%
Dividend yield		—			—			—			—
Expected term (years)		4.3			4.4			4.3			4.4
Resulting average fair value	$	22.35		$	13.52		$	18.05		$	12.74
Performance stock awards (1)
Risk-free interest rate		—			—			1.3	%		—
Volatility		—			—			33.4	%		—
Dividend yield		—			—			—			—
Expected term (years)		—			—			2.9			—
Resulting average fair value	$	—		$	—		$	82.58		$	—
Employee stock purchase plan
Risk-free interest rate		0.2	%		0.2	%		0.2	%		0.2	%
Volatility		21.5	%		26.5	%		21.5	%		26.5	%
Dividend yield		—			—			—			—
Expected term (years)		0.5			0.5			0.5			0.5
Resulting average fair value	$	12.27		$	9.65		$	12.27		$	9.65

⁽¹⁾ These assumptions apply to the Company’s market condition stock awards granted in 2011. Performance condition stock awards granted in 2010 were valued at $42.66 per share based on the closing fair market value of the Company’s common stock on the date of grant.

Unrecognized stock based compensation expense before income taxes and adjusted for estimated

	Weighted Average		Unrecognized
	Remaining		Expense as of
	Expense Life		June 30,
Awards	(Years)		2011
Stock options		2.8	$	33,759
Performance stock awards		2.6		6,567
Restricted stock		1.5		2,813
Deferred issuance restricted stock		1.5		788
Employee stock purchase plan		0.2		75
Total			$	44,002

Stock-based compensation expense

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2011		2010		2011		2010
Cost of product sales	$	794	$	1,006	$	1,582	$	1,870
Research and development		2,061		1,851		3,853		3,530
Marketing and sales		734		836		1,346		1,637
General and administrative		3,234		2,744		6,078		5,301
Total	$	6,823	$	6,437	$	12,859	$	12,338

Computation of basic and diluted EPS

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2011			2010			2011			2010
Basic Net Income per Share
Net income		22,344			28,110			45,621			52,303
Less: income allocated to participating securities		(37	)		(128	)		(72	)		(227	)
Net income allocated to common stockholders		22,307			27,982			45,549			52,076
Weighted average common shares outstanding — basic		47,884			48,902			47,873			49,066
Net income per share — basic	$	0.47		$	0.57		$	0.95		$	1.06
Diluted Net Income per Share
Net income		22,344			28,110			45,621			52,303
Less: income allocated to participating securities		(36	)		(126	)		(70	)		(225	)
Net income allocated to common stockholders		22,308			27,984			45,551			52,078
Weighted average common shares outstanding — basic		47,884			48,902			47,873			49,066
Dilutive securities		1,454			464			1,323			483
Weighted average common shares outstanding — diluted		49,338			49,366			49,196			49,549
Net income per share — diluted	$	0.45		$	0.57		$	0.93		$	1.05