Note 7 - Fair Value of Financial Instruments - (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Liabilities, Fair Value Disclosure, Recurring	$ 0	$ 0
Liabilities, Fair Value Disclosure, Nonrecurring	$ 0	$ 0

Aggregation of the liabilities reported on the balance sheet measured at fair value on a nonrecurring basis by the entity.

No definition available.

Name:	us-gaap_LiabilitiesFairValueDisclosureNonrecurring
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant