11. Stock-Based Compensation and Charges

The following chart summarizes the stock-based compensation and charges associated with stock option, restricted stock and restricted stock unit grants to employees and nonemployees, that have been included in the following financial statement captions for each of the periods presented (in thousands):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2013		2012		2013		2012
Cost of revenue	$	74	$	71	$	261	$	193
Sales and marketing	648		361		1,746		1,554
Product and web site development	723		527		2,050		1,412
General and administrative	1,297		1,037		4,184		2,697
Total stock-based compensation and charges	$	2,742	$	1,996	$	8,241	$	5,856

Stock Option Awards

The fair value of stock option awards was estimated on the date of grant using a Black-Scholes option valuation model that used the ranges of assumptions in the following table. The risk-free interest rates are based upon U.S. Treasury zero-coupon bonds for the periods during which the options were granted. The expected term of stock options granted represents the weighted-average period that the stock options are expected to remain outstanding. The Company has not declared and does not expect to declare dividends on its common stock; accordingly, the dividend yield for valuation purposes is assumed to be zero. The Company bases its computation of expected volatility upon a combination of historical and market-based implied volatility.

	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2013		2012	2013	2012
Risk-free interest rates	1.38	%	0.59%-0.67%	0.69%-1.41%	0.59%-1.04%
Expected term (in years)	5.85		5.85	5.85	5.85
Dividend yield	0	%	0%	0%	0%
Expected volatility	70	%	75%	70%-75%	75%

The total cost recognized related to stock option awards was $1.1 million and $1.3 million for the three months ended September 30, 2013 and 2012, respectively. For the nine months ended September 30, 2013 and 2012, the total cost recognized related to stock option awards was $3.4 million and $4.0 million, respectively.

Restricted Stock Awards

The Company grants restricted stock awards to the nonemployee members of its Board of Directors as remuneration for serving on its Board (except for any director who is entitled to a seat on the Board of Directors on a contractual basis or has waived remuneration as a director). The Company granted 45,959 and 52,265 shares of restricted stock to the nonemployee members of its Board of Directors during the nine months ended September 30, 2013 and 2012, respectively. These shares, subject to certain terms and restrictions, will vest over three years from the date of grant. The aggregate grant date fair value associated with the issuance of these shares was $0.5 million for the nine months ended September 30, 2013 and 2012. The total cost recognized for restricted stock awards granted to members of its Board of Directors was $0.1 million for the three months ended September 30, 2013 and 2012, and $0.3 million and $0.2 million for the nine months ended September 30, 2013 and 2012, respectively.

The Company also grants restricted stock awards to certain executives and key employees. Generally, these shares, subject to certain terms and restrictions, vest in equal annual installments over the four-year period following the grant date. The Company made no restricted stock award grants to the executives and key employees during the nine months ended September 30, 2013. During the nine months ended September 30, 2012, the Company granted 100,000 shares of restricted stock with an aggregate grant date fair value of $0.7 million that is being amortized over the vesting period. The total cost recognized for restricted stock awards granted to employees was $0.2 million for the three months ended September 30, 2013 and 2012, and $0.6 million and $0.8 million for the nine months ended September 30, 2013 and 2012, respectively.

As of September 30, 2013, there were 402,229 shares of nonvested restricted stock outstanding that were granted pursuant to restricted stock awards with an aggregate grant date fair value of $3.2 million.

Time-Vested Restricted Stock Units

The Company also grants time-vested restricted stock units. Generally, these restricted stock units, subject to certain terms and restrictions, vest in equal annual installments over the four-year period following the grant date, resulting in the issuance, on a one-for-one basis, of shares of our common stock after the vesting date. During the nine months ended September 30, 2013, the Company granted 939,386 restricted stock units with a grant date fair value of $9.8 million, which is being amortized over the four-year vesting period. During the nine months ended September 30, 2012, the Company granted 915,485 restricted stock units with a grant date fair value of $7.6 million, which is being amortized over the vesting period. In addition, there were 273,420 restricted stock units with a grant date fair value of $2.2 million provided to members of Tiger Lead Solution’s senior management pursuant to employment agreements, which were fully vested as of September 30, 2013. The total cost recognized for time-vested restricted stock units was $1.3 million and $0.4 million for the three months ended September 30, 2013 and 2012, respectively, and $3.8 million and $0.8 million for the nine months ended September 30, 2013 and 2012, respectively.

As of September 30, 2013, there were 1,506,833 nonvested restricted stock units outstanding with an aggregate grant date fair value of $14.5 million.