Note 11 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Year ended December 31,
	2017		2016
Research and development	$	95,040	$	674,643
General and administrative		1,145,511		716,425
Total stock-based compensation expense	$	1,240,551	$	1,391,068

Share-based Compensation, Stock Options, Activity [Table Text Block]

	Number of Options			Weighted average exercise price per share		Weighted average remaining contractual life (in years)		Aggregate Intrinsic Value (A)
Balance at January 1, 2016		1,495,615		$	3.92
RestorGenex options outstanding		301,156		$	40.13
Cancelled		(48,190	)	$	61.30
Granted		458,828		$	6.25
Balance at January 1, 2017		2,207,409		$	8.09		7.8	$	94,599
Granted		350,041			2.46
Expired		(1,461	)		15.00
Outstanding at December 31, 2017		2,555,989		$	7.32		7.13	$	4,734
Exercisable at December 31, 2017		1,858,073		$	8.25		6.49	$	4,734
Vested and expected to vest at December 31, 2017		2,555,989		$	7.32		7.13	$	4,734

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	2017			2016
Expected term (in years)	5.27	—	6.00	5.76	—	7.48
Risk-free interest rate	1.8%	—	2.4%	1.2%	—	2.0%
Expected volatility	109.8%	—	136.7%	106.8%	—	125.5%
Dividend yield	—			—