Note 7 - Leases - Maturity of Operating Lease Liabilities (Details) - USD ($)	Mar. 31, 2019	Jan. 01, 2019
2019 (remaining nine months)	$ 222,000
2020	303,000
2021	137,000
Total lease payments	662,000
Less: Interest	(87,000)
Present value of lease liabilities	$ 575,000	$ 629,000