Net Income (Loss) Per Share - Net Income (Loss) Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Net loss available to common stockholders	$ (13,049)	$ (4,813)	$ (26,451)	$ (21,320)
Denominator:
Weighted average shares outstanding - basic	37,036	35,879	36,967	35,838
Potential common shares - options (treasury stock method)
Weighted average shares outstanding - diluted	37,036	35,879	36,967	35,838
Shares excluded (anti-dilutive)			3	3
Shares excluded due to an exercise price greater than weighted average stock price for the period	2,271	1,453	2,261	1,453
Net loss per common share:
Basic	$ (0.35)	$ (0.13)	$ (0.72)	$ (0.59)
Diluted	$ (0.35)	$ (0.13)	$ (0.72)	$ (0.59)