Note 4 - Accounts Receivable, Net (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

	December 31,
(in thousands)	2018			2017
Accounts receivable	$	9,246		$	6,021
Less allowance for uncollectible accounts receivable		(88	)		—
Accounts receivable, net	$	9,158		$	6,021

Allowance for Credit Losses on Financing Receivables [Table Text Block]

	December 31,
(in thousands)	2018			2017		2016
Balance at beginning of period	$	—		$	—	$	—
Provision for bad debt expense		(88	)		—		—
Write-off		—			—		—
Balance at end of period	$	(88	)	$	—	$	—