Note 12 - Lease Commitments (Details Textual)		1 Months Ended
	Sep. 25, 2018 USD ($) ft²	Jun. 30, 2018 USD ($)	Aug. 31, 2015 USD ($) ft²	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 31, 2015 ft²	Mar. 01, 2013
Lessee, Operating Lease, Term of Contract							5 years
Lessee, Operating Lease, Renewal Term			2 years
Area of Real Estate Property | ft²	9,000		22,100			7,600
Operating Leases, Monthly Rent Expense	$ 17,000
Lessee Leasing Arrangements, Operating Leases, Optional Extension of Contract			5 years
Operating Lease, Right-of-Use Asset				$ 7,223,000
Operating Lease, Liability, Total				$ 8,267,000
Office Expansion [Member]
Operating Leases, Monthly Rent Expense			$ 12,000
Minimum [Member]
Operating Leases, Monthly Rent Expense		$ 39,000	36,000
Maximum [Member]
Operating Leases, Monthly Rent Expense		$ 79,000	$ 39,000