Note 13 - 401(k) Plan (Details Textual) - Pension Plan [Member] - The 401(k) Plan [Member] $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	90.00%
Defined Contribution Plan, Employers Contribution Vesting Period	4 years
Defined Contribution Plan, Cost	$ 0

Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration