Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits (Detail)

v3.8.0.1
Income Taxes - Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Income Tax Disclosure [Abstract]    
Beginning balance $ 1,875,337 $ 1,708,466
Additions based on tax positions related to the current year 140,313 166,871
Additions for the tax positions of prior years 0 0
Reductions for the tax positions of prior years 0 0
Ending balance $ 2,015,650 $ 1,875,337