Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				1 Months Ended	3 Months Ended		1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Employee Stock Option	Mar. 31, 2014 Unvested Restricted Common Stock	Jun. 14, 2013 Vested options held by 1 employees	Mar. 31, 2014 Vested options held by 1 employees	May 31, 2013 Vested options held by 1 employees	Jun. 14, 2013 Vested options held by 1 employees Before Extension	May 31, 2013 Vested options held by 1 employees Before Extension	Jun. 14, 2013 Vested options held by 1 employees After Extension	May 31, 2013 Vested options held by 1 employees After Extension
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted	80,500	110,900
Weighted-average grant date fair value	$ 3.34	$ 3.32
Unrecognized compensation costs	$ 7.1
Expected recognition period			1 year 8 months 5 days	1 year 1 month 6 days
Share Based Compensation Arrangement By Share Based Payment Award Option Fully Vested					71,167	71,167	66,667
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						9 months		3 months	3 months	12 months	12 months
Unrecognized compensation costs related to unvested restricted stock outstanding				$ 0.9