Note 12 - Commitments and Contingencies (Details Textual) - USD ($)
|3 Months Ended|
Mar. 31, 2018
Mar. 31, 2017
|Operating Leases, Rent Expense, Net, Total||$ 685,677||$ 744,295|
Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef