Note 16 - Subsequent Event (Details Textual) - USD ($)				3 Months Ended
	May 14, 2020	Apr. 29, 2020	Apr. 20, 2020	Mar. 31, 2020	May 22, 2020
Class of Warrant or Right, Exercised During Period (in shares)				2,000
Subsequent Event [Member]
Proceeds from Paycheck Protection Program Under CARES Act			$ 2,175,320
Repayments of Loan From Paycheck Protection Program Under CARES Act		$ 2,175,320
Subsequent Event [Member] | WAVI Holding AG and Taurus4757 GmbH Warrants [Member]
Stock Issued During Period, Shares, Warrant Exercises (in shares)	2,747,970
Class of Warrant or Right, Exercised During Period (in shares)	3,871,405
Subsequent Event [Member] | Casdin Capital LLC [Member]
Share Repurchase Agreement, Amount of Shares to be Issued	$ 20,000,000				$ 20,000,000
Share Repurchase Agreement, Shares Issued, Price Per Share (in dollars per share)	$ 10.50
Share Repurchase Agreement, Shares to be Issued (in shares)	1,904,762