Note 6 - Advances on Contracts (Details Textual) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Advances on Inventory Purchases	$ 861,782	$ 697,192

Carrying value of capitalized payments made in advance for inventory that is expected to be received within one year or the normal operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_AdvancesOnInventoryPurchases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant