Note 8 - Related Party (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Ameritas Life Insurance Corp [Member]
Related Party Transaction, Amounts of Transaction	$ 62,000	$ 57,000	$ 120,000	$ 115,000
Nebraska Global Investment Company LLC [Member]
Related Party Transaction, Amounts of Transaction		$ 204,000	$ 0	$ 420,000
Nebraska Global Investment Company LLC [Member] | Chief Executive Officer [Member]
Officer Ownership Percentage in Vendor	14.00%		14.00%