CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	51,925	51,709
Common stock, shares outstanding	51,925	51,709
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000	5,000
Series A Junior Participating Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	100	100
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0