Credit Facility (Detail)	3 Months Ended
	Mar. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 2,500,000
Credit facility expiration date	Jan. 15, 2019
Credit facility limit restricted to support letter of credit	$ 226,731
Line of credit facility, remaining borrowing capacity	$ 2,300,000
Prime Rate
Line of Credit Facility [Line Items]
Interest rate over prime rate	0.50%