STOCKHOLDERS' EQUITY (Detail Textuals) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended		1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Apr. 30, 2012 Common Stock	Jan. 31, 2011 Common Stock	Dec. 31, 2012 Purchase Plan Common Stock
Class of Stock [Line Items]
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Issuance of common stock from stock offering, net (in shares)			8,222,500	8,050,000
Common stock, per share amount			$ 7.30	$ 6.15
Proceeds from stock offering, net	$ 56,256	$ 46,756	$ 56,300	$ 46,800
Common shares reserved for future issuance under the employee stock purchase plan					585,033