Note 5 - Accounts Receivable - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable, net	$ 10,569	$ 3,803
Royalties [Member]
Accounts receivable, net	3,593	3,151
Bayer Milestone [Member]
Accounts receivable, net	2,000
FUJIFILM Transfer [Member]
Accounts receivable, net	4,000
Other [Member]
Accounts receivable, net	$ 976	$ 652