Equity-based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended				1 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Performance-based [Member]	Jun. 30, 2013 Equity Incentive Plan [Member] Maximum [Member]	Jul. 31, 2013 Equity Incentive Plan [Member] Subsequent Event [Member]	Jul. 19, 2013 Equity Incentive Plan [Member] Subsequent Event [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved				1,200,000		2,600,000
Term of award determination	10 years
Options available for grant	637,993
Additional number of shares of common stock reserved					1,400,000
Fair value of shares vested	$ 0.6
Total unrecognized compensation cost	$ 0.1		$ 0.3
Weighted-average period to recognize the compensation cost	1 year 1 month 6 days
Fair market value of options granted	$ 2.07	$ 5.75