Note 7 - Industry Segment Data (Details Textual) - USD ($)	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Payments to Acquire Property, Plant, and Equipment	$ 799,331	$ 2,124,649
Construction in Progress [Member]
Payments to Acquire Property, Plant, and Equipment	$ 9,452,000

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

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