Note 5 - Accounts Receivable (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

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

	March 31,		December 31,
	2019		2018
Royalties	$	4,161	$	3,151
Other		774		652
Accounts receivable, net	$	4,935	$	3,803