Note 3 - Reserve for Sales Returns and Allownace - Reserve for Sales Returns and Allowances (Details) - Allowance for Sales Returns [Member] - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance at the beginning of year	$ 1,384,000	$ 1,308,000	$ 793,000
Provision for returns and allowances	4,445,000	4,547,000	6,024,000
Actual returns and allowances paid to customers	(3,862,000)	(4,471,000)	(5,509,000)
Balance at the end of year	$ 1,967,000	$ 1,384,000	$ 1,308,000