Note 5 - Other Balance Sheet Information (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2019

Dec. 31, 2018

Notes Tables

Schedule of Prepaid and Other Current Assets [Table Text Block]


		December 31, 2018			June 30, 2019
Prepaid clinical trial expenses		$	5		$	435
Equity issuance costs		—			343
Prepaid insurance		—			670
Other prepaid expenses		5			174

Total prepaid and other current assets		$	10		$	1,622

Schedule of Accrued Liabilities [Table Text Block]


		December 31, 2018			June 30, 2019
Payroll and related expenses		$	241		$	508
Accrued term loan final payment		421			569
Accrued clinical trial expense		—			8
Professional fees and other costs		195			395

Total accrued liabilities		$	857		$	1,480


		As of December 31,
		2017			2018
Payroll and related expenses		$	273		$	241
Accrued term loan final payment			197			421
Accrued clinical trial expense			654			—
Professional fees and other costs			34			195
Total accrued liabilities		$	1,158		$	857