Note 4 - Leases, Right-to-Use Assets and Related Liabilities (Details Textual) $ in Thousands	Jun. 30, 2019 USD ($)	Jan. 01, 2019 USD ($)
Leases Containing Variable Payments	0
Leases Containing Extension or Termination Options	0
Lessee, Operating Lease, Discount Rate	12.00%
Lessee, Operating Lease, Lease Not yet Commenced, Amount	2
Lessee, Operating Lease, Right-of-Use Asset, Not yet Commenced, Fair Value	$ 3,000
Lessee, Operating Lease, Liability, Not yet Commenced, Fair Value	3,000
Deposits and Other Assets [Member]
Operating Lease, Right-of-Use Asset	400
Accounts Payable and Accrued Liabilities [Member]
Operating Lease, Liability, Total	300
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Total	$ 300
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset		$ 1,200
Operating Lease, Liability, Total		$ 1,200