Quarterly report pursuant to Section 13 or 15(d)

Carrying Amounts and Fair Values of Company's Financial Instruments (Detail)

v3.8.0.1
Carrying Amounts and Fair Values of Company's Financial Instruments (Detail) - USD ($)
Mar. 31, 2018
Dec. 31, 2017
Assets    
Assets, Fair Value Disclosure $ 43,439,295 $ 42,374,500
Fair Value, Inputs, Level 1 [Member]    
Assets    
Assets, Fair Value Disclosure 43,439,295 42,374,500
Fair Value, Inputs, Level 2 [Member]    
Assets    
Assets, Fair Value Disclosure 0 0
Fair Value, Inputs, Level 3 [Member]    
Assets    
Assets, Fair Value Disclosure 0 0
Money Market Funds [Member]    
Assets    
Assets, Fair Value Disclosure [1] 42,300,818 41,231,405
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets    
Assets, Fair Value Disclosure [1] 42,300,818 41,231,405
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets    
Assets, Fair Value Disclosure [1] 0 0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets    
Assets, Fair Value Disclosure [1] 0 0
Certificates of Deposit [Member]    
Assets    
Assets, Fair Value Disclosure 1,061,022 1,057,090
Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets    
Assets, Fair Value Disclosure 1,061,022 1,057,090
Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets    
Assets, Fair Value Disclosure 0 0
Certificates of Deposit [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets    
Assets, Fair Value Disclosure 0 0
Equity Securities [Member]    
Assets    
Assets, Fair Value Disclosure 77,455 86,005
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets    
Assets, Fair Value Disclosure 77,455 86,005
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets    
Assets, Fair Value Disclosure 0 0
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets    
Assets, Fair Value Disclosure $ 0 $ 0
[1] Included in cash and cash equivalents