Secured Revolving Credit Facility - Additional Information (Detail) - USD ($)		1 Months Ended							12 Months Ended
	Mar. 20, 2015	Dec. 31, 2016	Jul. 31, 2016	Jun. 30, 2016	May 31, 2016	Feb. 29, 2016	Jan. 31, 2016	Dec. 31, 2015	May 31, 2017	May 31, 2016
Line of Credit Facility [Line Items]
Expected monthly loss related to covenants					$ 500,000	$ 1,000,000	$ 1,000,000	$ 1,500,000		$ 500,000
Subsequent Event [Member]
Line of Credit Facility [Line Items]
Expected monthly loss related to covenants			$ 1,000,000	$ 500,000
Increased From [Member]
Line of Credit Facility [Line Items]
Covenants limit on capital expenditures per year										800,000
Increased To [Member]
Line of Credit Facility [Line Items]
Covenants limit on capital expenditures per year										$ 1,250,000
Scenario Forecast [Member]
Line of Credit Facility [Line Items]
Expected monthly loss related to covenants		$ 1,000,000							$ 250,000
Scenario Forecast [Member] | Increased From [Member]
Line of Credit Facility [Line Items]
Covenants limit on capital expenditures per year									800,000
Scenario Forecast [Member] | Increased To [Member]
Line of Credit Facility [Line Items]
Covenants limit on capital expenditures per year									$ 1,500,000
Secured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 10,000,000
Credit facility, interest rate	3.75%
Interest rate description										Loan advances bear interest at 3.75% in excess of The Wall Street Journal's published one year LIBOR rate
Secured revolving credit facility term	3 years
Secured revolving credit facility renewal term	1 year
Covenants limit on capital expenditures per year	$ 600,000									$ 800,000
Percentage of monthly bank assessment fees per annum	0.25%									0.35%