Note 12 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]

	Investments at Fair Value as of December 31, 2017
(in thousands)	Level 1		Level 2		Level 3			Total
Warrant liabilities		-		-		(2,387	)		(2,387	)
Total warrant liabilities	$	-	$	-	$	(2,387	)	$	(2,387	)

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	Level 3 Liabilities
(in thousands)	Warrant Liabilities
Balance at January 1, 2017	$	-
New warrants issued		3,080
Unrealized losses, net		2,608
Settlement of warrants		(3,301	)
Balance at December 31 ,2017	$	2,387