Summary of Warrants and Options Issued to Employees and Directors (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value Exercisable		$ 161,511
Employee Stock Options And Warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period	1,030,807	682,141	259,299
Exercised	(129,265)	0	0
Expired	(1,000)	(1,334)	(3,000)
Forfeited, Number of Warrants and Options	0	0	0
Granted, Number of Warrants and Options	97,890	350,000	425,842
Balance at end of period	998,432	1,030,807	682,141	259,299
Exercisable, Number of Warrants and Options	673,473	410,593	262,952
Balance at beginning of period	$ 6.39	$ 6.47	$ 7.75
Exercised, Weighted Average Exercise Price	7.35	0	0
Expired, Weighted Average Exercise Price	5.14	5.70	5.33
Forfeited, Weighted Average Exercise Price	0	0	0
Granted, Weighted Average Exercise Price	7.11	6.25	5.68
Balance at end of period	6.34	6.39	6.47	$ 7.75
Exercisable, Weighted Average Exercise Price	$ 6.41	$ 6.80	$ 7.31
Weighted Average Remaining Contract Life Outstanding	7 years 6 months 29 days	8 years 2 months 8 days	8 years 6 months 7 days	7 years 8 months 8 days
Aggregate Intrinsic Value Beginning Balance	$ 320,637	$ 88,000	$ 0
Aggregate Intrinsic Value Ending Balance	1,205,839	$ 320,637	88,000	$ 0
Aggregate Intrinsic Value Exercisable	$ 789,356		$ 9,252