Note 13 - Employee Equity Incentive Plans - Status of Non-vested Shares (Details) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Shares underlying stock options (in shares)	4,875,000	487,500
Weighted average grant date fair value (in dollars per share)	$ 0.21	$ 0.19

Weighted average grant-date fair value of non-vested options outstanding.

No definition available.

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant