Summary of Significant Accounting Policies - Summary of Cumulative Effect Adjustments Resulting from Adoption of New Standard, Including Income Tax Implications (Detail) - USD ($)	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
ASSETS
Deferred tax asset, net	$ 11,683,895	$ 11,483,895	$ 12,072,118
Other assets	3,238,422	3,327,633	217,161
Total assets	119,357,320	124,125,982	121,603,733
Liabilities
Accrued expenses and other liabilities	4,825,408	4,832,654	4,149,363
Deferred revenue	25,890,104	26,558,707	26,533,983
Other long-term liabilities	2,531,017	2,580,952	2,447,037
Total liabilities	33,246,529	33,972,313	33,130,383
Equity
Retained earnings (deficit)	(24,681,312)	(19,437,282)	(21,117,601)
Total stockholders' equity	$ 86,110,791	90,153,669	$ 88,473,350
ASU 2014-09 [Member]
ASSETS
Deferred tax asset, net		(588,223)
Other assets		3,110,472
Total assets		2,522,249
Liabilities
Accrued expenses and other liabilities		683,291
Deferred revenue		24,724
Other long-term liabilities		133,915
Total liabilities		841,930
Equity
Retained earnings (deficit)		1,680,319
Total stockholders' equity		$ 1,680,319