Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2013

We used the Black-Scholes option pricing model to estimate the fair value of stock options granted with the following assumptions:


	Six Months Ended June 30, 2013
Assumed forfeiture rate (annual %)		5.0	%
Expected dividend yield		0.0	%
Assumed stock price volatility		63.5	%
Weighted average risk-free rate		1.10	%
Expected life (years)		6.25

Options activity under the Option Plan for the six month period ended June 30, 2013 is summarized as follows:


	Stock Options Issued and Outstanding			Weighted Average Exercise Price
Balances, at December 31, 2012		10,255,222		$	1.19
Options Granted		1,566,750			5.81
Options Exercised		(1,323,933	)		0.43
Options Forfeited/Expired		(60,002	)		1.70

Balances, June 30, 2013		10,438,037		$	1.98

A summary of outstanding options, options vested and options vested and expected to vest as of June 30, 2013, is as follows:


	Stock Options Issued and Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
Options Outstanding		10,438,037		8.49	$	1.98
Options Vested		2,949,875		7.33	$	0.61
Options Vested and Expected to Vest		9,944,411		8.46	$	1.92

A summary by weighted average exercise price of outstanding options, options vested, and options expected to vest at June 30, 2013, is as follows:


Weighted Average Exercise Price	Stock Options Outstanding		Weighted Average Remaining Contractual Life of Outstanding Stock Options (Years)		Number of Stock Options Vested		Number of Stock Options Vested and Expected to Vest
$0.23		391,688		6.41		349,625		391,323
$0.41		2,916,177		7.03		1,811,298		2,885,350
$0.71		2,493,197		8.68		582,080		2,378,871
$2.78		3,458,225		9.35		206,872		3,225,198
$6.77		1,178,750		9.87		—		1,063,669

$1.98		10,438,037		8.49		2,949,875		9,944,411