Stock-Based Compensation - Summary of Status of Stock Option Plans (Detail) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Summary of the status of the stock option plans
Options outstanding, January 1, shares	120,617
Granted, shares	89,500
Forfeited, shares
Exercised, shares
Expired, shares	(7,596)
Options outstanding, June 30	202,521	120,617
Options exercisable, June 30	202,521
Options outstanding, January 1, Weighted Average Exercise Price	$ 9.51
Granted, Weighted Average Exercise Price	$ 5.25
Forfeited, Weighted Average Exercise Price
Exercised, Weighted Average Exercise Price
Expired, Weighted Average Exercise Price	$ 13.80
Options outstanding, June 30, Weighted Average Exercise Price	$ 7.46	$ 9.51
Options exercisable, June 30, Weighted Average Exercise Price	$ 7.46
Options outstanding, January 1, Remaining Contractual Life	7 years 2 months 12 days	5 years 4 months 24 days
Options exercisable, June 30, Remaining Contractual Life	7 years 2 months 12 days
Options outstanding, June 30, Aggregate Intrinsic Value	$ 9,425
Options exercisable, June 30, Aggregate Intrinsic Value	$ 9,425