Intrinsic Value of Options Exercised and Fair Value of Options Vested (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of common stock options exercised	$ 10	[1]
Fair value of common stock options vested	$ 327	[2]

[1] The intrinsic value of common stock options exercised is the difference between the fair market value of the Company's common stock on the exercise date and the exercise price.

[2] The fair value of common stock options vested is based on the grant date fair value.