Net Income (Loss) Per Share - Net Income (Loss) Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerator:
Net loss available to common stockholders	$ (5,167)	$ (6,158)
Denominator:
Weighted average shares outstanding - basic	37,714	36,614
Potential common shares - options (treasury stock method)
Weighted average shares outstanding - diluted	37,714	36,614
Shares excluded (anti-dilutive)	186	70
Shares excluded due to an exercise price greater than weighted average stock price for the period	1,340	1,473
Net loss per common share:
Basic	$ (0.14)	$ (0.17)
Diluted	$ (0.14)	$ (0.17)