Note 5 - Accounts Receivable - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts receivable, gross	$ 38,619	$ 38,981
Less: allowance for doubtful accounts	(3,415)	(4,627)
Accounts receivable, net	35,204	34,354
Retail Customers [Member]
Accounts receivable, gross	22,412	22,101
Wholesale Carriers [Member]
Accounts receivable, gross	10,049	13,157
Other [Member]
Accounts receivable, gross	$ 6,158	$ 3,723