Note 11 - Stock-based Compensation - Stock Option Activity (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Options outstanding, number (in shares)		2,207,409	1,495,615
Options outstanding, weighted-average exercise price (in dollars per share)		$ 8.09	$ 3.92
RestorGenex options outstanding (in shares)			301,156
RestorGenex options outstanding, weighted-average exercise price (in dollars per share)			$ 40.13
Cancelled (in shares)			(48,190)
Cancelled, weighted-average exercise price (in dollars per share)			$ 61.30
Granted (in shares)		350,041	458,828
Granted, weighted-average exercise price (in dollars per share)		$ 2.46	$ 6.25
Options outstanding, weighted-average remaining contractual life (Year)		7 years 47 days	7 years 292 days
Options outstanding, aggregate intrinsic value	[1]	$ 4,734	$ 94,599
Expired (in shares)		(1,461)
Expired, weighted-average exercise price (in dollars per share)		$ 15
Options outstanding, number (in shares)		2,555,989	2,207,409
Options outstanding, weighted-average exercise price (in dollars per share)		$ 7.32	$ 8.09
Exercisable (in shares)		1,858,073
Exercisable, weighted-average exercise price (in dollars per share)		$ 8.25
Exercisable, weighted-average remaining contractual life (Year)		6 years 178 days
Exercisable, aggregate intrinsic value	[1]	$ 4,734
Vested and expected to vest (in shares)		2,555,989
Vested and expected to vest, weighted-average exercise price (in dollars per share)		$ 7.32
Vested and expected to vest, weighted-average remaining contractual life (Year)		7 years 47 days
Vested and expected to vest, aggregate intrinsic value	[1]	$ 4,734

[1] The difference, if positive, between the stock option's exercise price and the closing price of the Company's common stock at December 31, 2017.