STOCKHOLDERS' EQUITY (Details)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Stockholders' Equity
Shares issued pursuant to stock option exercises		2,897
Restricted common stock
Stockholders' Equity
Shares vested	417,252	193,228
Shares held to satisfy the employees' tax liability	72,594	27,436
Restricted common stock | Employees
Stockholders' Equity
Shares granted	642,000	948,000
Restricted common stock | New employees
Stockholders' Equity
Shares granted		4,000