Note 4 - Accounts Receivable, Net (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss, Current		$ 1,324		$ 3,393
Accounts Receivable, Credit Loss Expense (Reversal)		445	$ 1,521
Internet Advertising and TV Advertising [Member]
Accounts Receivable, Allowance for Credit Loss, Current		$ 1,300		$ 3,400
Number of Months Past Due		180 days
Accounts Receivable, Credit Loss Expense (Reversal)	$ (40)	$ 450	$ 760
Accounts Receivable, Allowance for Credit Loss, Writeoff		$ 2,400