Note 3 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

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

	Fair Value Measurements Using
(in thousands)	Balance at June 30, 2017		Quoted Prices in Active Markets for Identical Items (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	101	$	101	$	—	$	—
Restricted cash held as a certificate of deposit		324		324		—		—
Deposit held as a certificate of deposit		150		150		—		—
Total assets	$	575	$	575	$	—	$	—
Liabilities
Warrant liability	$	1,608	$	—	$	—	$	1,608
Total liabilities	$	1,608	$	—	$	—	$	1,608

	Fair Value Measurements Using
(in thousands)	Balance at December 31, 2016		Quoted Prices in Active Markets for Identical Items (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	100	$	100	$	—	$	—
Restricted cash held as a certificate of deposit		324		324		—		—
Deposit held as a certificate of deposit		150		150		—		—
Total assets	$	574	$	574	$	—	$	—
Liabilities
Warrant liability	$	1,446	$	—	$	—	$	1,446
Total liabilities	$	1,446	$	—	$	—	$	1,446

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

(in thousands)	Warrant liability
Fair value of warrant liability at December 31, 2016	$	1,446
Increase in fair value at March 31, 2017		235
Fair value of warrant liability at March 31, 2017		1,681
Decrease in fair value at June 30, 2017		(15	)
Fair market value of warrants transferred to equity upon exercise		(58	)
Fair value of warrant liability at June 30, 2017	$	1,608