Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2011

Sep. 30, 2010

Stockholders' Equity [Abstract]

Summary Of Activity Related To Stock Option Plans

	Shares Available for Grant			Options Outstanding					Weighted-Average Remaining Contractual Term (in Years)		Aggregate Intrinsic Value (in Thousands)
				Number of Shares			Weighted- Average Exercise Price
Balances as of December 31, 2010		2,038,502			2,892,130		$	36.11
Granted		(341,474	)		341,474			234.67
Exercised		—			(621,989	)		29.88
Balances as of September 30, 2011		1,697,028			2,611,615			63.55		5.95	$	176,151
Vested and exercisable at September 30, 2011					2,611,615			63.55		5.95	$	176,151

Summary Of Assumptions Used To Value Stock Option Grants Using Lattice-Binomial Model

	Three Months Ended		Nine Months Ended
	September 30, 2011	September 30, 2010	September 30, 2011	September 30, 2010
Dividend yield	0%	0%	0%	0%
Expected volatility	52%	54%	51-52%	46-54%
Risk-free interest rate	2.98%	2.97%	2.98-3.42%	2.97-3.67%
Suboptimal exercise factor	2.26-3.63	2.00-2.40	2.17-3.63	1.78-2.40

Summary Of Assumptions Used To Value Employee Stock Purchase Rights

	Nine Months Ended  September 30, 2010
Dividend yield		0	%
Expected volatility		45	%
Risk-free interest rate		0.24	%
Expected life (in years)		0.5

Summary Of Stock-Based Compensation Expense

	Three Months Ended September 30,						Nine Months Ended September 30,
	2011			2010			2011			2010
	(in thousands)
Fulfillment expense	$	206		$	323		$	1,446		$	806
Technology and development		7,522			2,694			19,819			6,939
Marketing		1,539			777			4,273			2,176
General and administrative		6,438			3,502			17,967			9,805
Stock-based compensation expense before income taxes		15,705			7,296			43,505			19,726
Income tax benefit		(5,228	)		(3,064	)		(16,066	)		(8,118	)
Total stock-based compensation after income taxes	$	10,477		$	4,232		$	27,439		$	11,608