SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2014

SHARE-BASED COMPENSATION.

Schedule of share-based compensation expense by type of award

	Years ended December 31,
	2012		2013		2014
Share options	$	792,691	$	671,768	$	387,817
Non-vested restricted shares		1,413,789		1,470,677		1,840,614
Total share-based compensation	$	2,206,480	$	2,142,445	$	2,228,431

Schedule of key assumptions used to estimate grant date fair value of options granted

	2012
Risk-free interest rate	2.51%-3.04%
Expected term	—
Contractual term	8.78-10 years
Expected volatility rate	54.57%-57.16%
Dividend yield	0%

Summary of option activity and information regarding options outstanding

	Number of options			Weighted average exercise price		Weighted average remaining contract terms	Aggregate intrinsic value
Options outstanding at January 1, 2014		27,999,840		$	0.16
Forfeited		(5,323,780	)	$	0.21
Exercised		(5,157,820	)	$	0.09
Options outstanding at December 31, 2014		17,518,240		$	0.17	6.6 years		701,202
Options vested or expected to vest at December 31, 2014		16,642,328		$	0.11	3.1 years		666,142
Options exercisable at December 31, 2014		13,275,740		$	0.15	6.4 years		701,202

Summary of non-vested restricted shares activities under share incentive plan and information regarding restricted shares outstanding

	Number of Non-vested Restricted Shares			Weighted average grant-date fair value
Non-vested as of January 1, 2014		19,040,414			0.32
Granted		2,660,000			0.32
Forfeited		(7,553,727	)		0.32
Vested		(4,803,671	)		0.40
Non-vested as of December 31, 2014		9,343,016			0.28