Note 10 - Government Grants and Contracts (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue from Grants	$ 295,735	$ 47,600	$ 828,918	$ 428,081	$ 882,956
NIH Grants [Member]
Revenue from Grants	295,735	$ 47,600	828,918	$ 428,081	$ 882,956
Unused Grant Funds	$ 867,911		$ 505,487

Revenue earned during the period from non-repayable sum of money awarded to an entity to carry out a specific purpose as provided in grant agreements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_RevenueFromGrants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration