Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Convertible senior notes interest rate	5.00%	5.00%
Convertible preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Convertible preferred stock, shares issued	0	0
Convertible preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	185,000,000	185,000,000
Common stock, shares issued	115,717,000	114,787,000
Common stock, shares outstanding	115,717,000	114,787,000