Summary of Significant Accounting Policies - Reconciliation of the Numerator and Denominator Used in the Calculation of Basic and Diluted Net (Loss) Income Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Numerator:
Net (loss) income	$ (1)	$ 577	$ (871)	$ (1,542)	$ 1,022	$ 672	$ 1,965	$ 365	$ (1,837)	$ 4,024	$ 4,689
Basic:
Weighted average shares of common stock and vested restricted stock awards outstanding									37,886,492	40,211,075	38,531,645
Diluted:
Weighted average shares of common stock and vested restricted stock awards outstanding									37,886,492	40,211,075	38,531,645
Effect of potentially dilutive shares										698,668	2,035,806
Total weighted average shares of common stock and vested restricted stock awards outstanding									37,886,492	40,909,743	40,567,451
Basic:
Net (loss) income applicable to common stockholders	(1)	577	(871)	(1,542)	1,022	672	1,965	365	(1,837)	4,024	4,689
Weighted average shares of stock outstanding									37,886,492	40,211,075	38,531,645
Net (loss) income per common share	$ 0.00	$ 0.01	$ (0.02)	$ (0.04)	$ 0.03	$ 0.02	$ 0.05	$ 0.01	$ (0.05)	$ 0.10	$ 0.12
Diluted:
Net (loss) income applicable to common stockholders	$ (1)	$ 577	$ (871)	$ (1,542)	$ 1,022	$ 672	$ 1,965	$ 365	$ (1,837)	$ 4,024	$ 4,689
Weighted average shares of stock outstanding									37,886,492	40,909,743	40,567,451
Net (loss) income per common share	$ 0.00	$ 0.01	$ (0.02)	$ (0.04)	$ 0.02	$ 0.02	$ 0.05	$ 0.01	$ (0.05)	$ 0.10	$ 0.12