Income Taxes - Significant Components of Company's Deferred Tax Assets and Liabilities (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets
Net operating loss carryforwards	$ 14,561,655	$ 17,314,368
Asset basis differences - tax amount greater than book value	0	254,773
Liability reserves	792,075	187,253
Stock compensation plans	1,828,185	1,644,339
AMT credit carryforwards	1,717,792	1,576,737
Other	57,153	45,903
Deferred tax assets, gross	18,956,860	21,023,373
Valuation allowance	0	0
Total deferred tax assets	18,956,860	21,023,373
Deferred Tax Liabilities
Acquired asset differences - book value greater than tax	(1,842,450)	(2,266,160)
Asset basis differences - carrying amount value greater than tax	(299,673)	(327,476)
Total deferred tax liabilities	(2,142,123)	(2,593,636)
Net deferred tax asset (liability)	$ 16,814,737	$ 18,429,737