Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2013

Equity [Abstract]

Summary Of Stock-Based Compensation Expense Related To Employee Stock Options

The following table summarizes stock-based compensation expense related to employee stock options under ASC 718-10 included in Company’s statement of operations for the years ended (amounts in thousands):

	December 31,
	2013		2012		2011
Cost of revenue	$	1,954	$	1,579	$	1,023
Sales and marketing	2,851		2,878		1,668
General and administrative expense	4,148		3,294		2,377
Product development expense	3,555		2,964		1,703
Total stock based compensation included in operating expenses	$	12,508	$	10,715	$	6,771

Weighted Average Assumptions Of Fair Value Options Using Black-Scholes Option-Pricing Model

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions for the years ended December 31, 2013, 2012 and 2011:

	December 31,
	2013	2012	2011
Dividend yield	—%	—%	—%
Risk-free interest rate	0.7% – 1.4%	0.6% – 0.9%	0.9% – 3.7%
Expected life (in years)	5.0	5.0	5.0
Historical volatility	55.6% – 60.1%	59.3% – 60.8%	60.1% – 61.5%

Summary Of Stock Option Activity And Weighted Average Exercise Prices

A summary of the Company’s stock option activity and weighted average exercise prices follows:

	Options		Weighted Average Exercise Price
Options outstanding at December 31, 2010	8,816,760		$	5.04
Options granted	3,642,600		12.24
Options exercised	(2,278,451	)	4.28
Options cancelled	(1,337,496	)	7.03
Options outstanding at December 31, 2011	8,843,413		7.91
Options granted	3,463,500		16.20
Options exercised	(1,634,658	)	5.10
Options cancelled	(830,776	)	10.78
Options outstanding at December 31, 2012	9,841,479		11.06
Options granted	2,573,700		10.20
Options exercised	(771,810	)	6.48
Options cancelled	(1,919,176	)	13.11
Options outstanding at December 31, 2013	9,724,193		$	10.86
Options exercisable at December 31, 2011	2,805,399		$	4.63
Options exercisable at December 31, 2012	3,220,228		$	6.61
Options exercisable at December 31, 2013	4,090,492		$	8.71

Summary Of The Status Of Nonvested Options

A summary of the status of the Company’s nonvested options as of December 31, 2011, and changes during the years ended December 31, 2012 and 2013 is as follows:

	Shares		Weighted Average Grant-Date Fair Value
Nonvested Shares at December 31, 2011	6,038,014		$	5.04
Granted	3,463,500		8.20
Vested	(2,060,707	)	4.46
Cancelled	(819,556	)	5.69
Nonvested Shares at December 31, 2012	6,621,251		$	6.84
Granted	2,573,700		5.12
Vested	(1,927,755	)	6.05
Cancelled	(1,633,495	)	6.74
Nonvested Shares at December 31, 2013	5,633,701		$	6.90