Note 3 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

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

			Fair Value Measurements Using
(in thousands)	Balance at March 31, 2019		Quoted Prices in  Active Markets  for Identical  Items  (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	103	$	103	$	—	$	—
Restricted cash held as a certificate of deposit		324		324		—		—
Deposit held as a certificate of deposit		151		151		—		—
Total assets	$	578	$	578	$	—	$	—
Liabilities
Warrant liability	$	179	$	—	$	—	$	179
Derivative liability		427		—		—		427
Total liabilities	$	606	$	—	$	—	$	606

			Fair Value Measurements Using
(in thousands)	Balance at December 31, 2018		Quoted Prices in Active Markets for Identical Items (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	103	$	103	$	—	$	—
Restricted cash held as a certificate of deposit		324		324		—		—
Deposit held as a certificate of deposit		151		151		—		—
Total assets	$	578	$	578	$	—	$	—
Liabilities
Warrant liability	$	178	$	—	$	—	$	178
Total liabilities	$	178	$	—	$	—	$	178

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

	Level 3
(in thousands)	liabilities
Balance at December 31, 2018	$	178
Fair value of warrant liability reclass to equity-Adoption of ASU 2017-11		(56	)
Increase in fair value of warrant liability at March 31, 2019		57
Embedded derivative liability associated with the convertible note		427
Fair value of warrant liability and embedded derivative liability at March 31, 2019	$	606