Note 2 - Summary of Significant Accounting Policies - Cumulative Effect of Adjustments for New Accounting Pronouncements on Consolidated Balance Sheet (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	[1]
Other assets		$ 646	$ 800	$ 171
Total assets		25,496	47,463	46,834
Accrued liabilities		5,278	6,996	6,766
Total current liabilities		6,884	10,990	10,760
Other noncurrent liabilities		1,010	1,033	634
Total liabilities		39,165	42,551	41,922
Total liabilities and stockholders' equity		$ 25,496	47,463	$ 46,834
Accounting Standards Update 2016-02 [Member]
Other assets	[2]		629
Total assets	[2]		629
Accrued liabilities	[3]		230
Total current liabilities	[3]		230
Other noncurrent liabilities	[3]		399
Total liabilities	[3]		629
Total liabilities and stockholders' equity	[3]		$ 629

[1] The condensed consolidated balance sheet as of December 31, 2018 has been derived from the audited consolidated financial statements as of that date.

[2] Represents capitalization of operating lease right-of-use assets and reclassification of deferred rent.

[3] Represents recognition of operating lease liabilities.