Note 9 - Preferred Stock and Common Stock Warrants (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]

	December 31,			December 31,
	2019			2018
Stock price	$	6.14		$	5.40
Exercise price	$	0.01		$	0.01
Risk-free rate		1.6	%		2.5	%
Volatility		27.6	%		33.1	%
Term (years)		1.8			2.7

Schedule of Allocation of Net Cash Proceeds [Table Text Block]

			Year Ended December 31, 2019
					Series B
			Series B		Convertible
			Warrants		Preferred
Gross proceeds	$	20,945
Equity issuance costs		—
Net proceeds - Initial Fair Value Allocation	$	20,945	$	1,936	$	19,009
Per balance sheet upon issuance			$	1,936	$	19,009

				Year Ended December 31, 2018
													Additional Paid-in Capital
								Series A			Series B				Beneficial
				Series A		Series B		Convertible			Convertible		Common		Conversion
				Warrants		Warrants		Preferred			Preferred		Stock		Feature
Gross proceeds	$	79,055
Equity issuance costs		(2,104	)
Net proceeds - Initial Fair Value Allocation	$	76,951		$	4,859	$	2,746	$	41,079		$	26,159	$	2,108	$	—
Allocation to BCF					—		—		(2,530	)		—		—		2,530
Per balance sheet upon issuance				$	4,859	$	2,746	$	38,549		$	26,159	$	2,108	$	2,530