Note 3 - Income Taxes (Details Textual)				1 Months Ended	3 Months Ended		6 Months Ended
	May 02, 2017 USD ($)	Jul. 18, 2016 USD ($)	Nov. 24, 2015 USD ($)	May 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Income Tax Expense (Benefit)					$ 281,000	$ 375,000	$ 655,000	$ 3,000
Effective Income Tax Rate Reconciliation, Percent							27.70%	0.10%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent							34.00%
Estimated Future Liquidation Loss on Tax Attributes					2,900,000		$ 2,900,000
Deferred Tax Assets, Valuation Allowance			$ 11,661,000		13,791,000	12,770,000	13,791,000	$ 12,770,000
Deferred Income Tax Expense (Benefit)							(501,880)
Business Combination, Bargain Purchase, Gain Recognized, Amount, Net							$ 501,880
Delphax [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards						6,300,000		6,300,000
Delphax [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards						13,200,000		13,200,000
Delphax [Member] | Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount						4,300,000		4,300,000
Delphax [Member] | Domestic Tax Authority [Member] | Alternative Minimum Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount						311,000		311,000
Delphax Canada [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards						4,000,000		4,000,000
Tax Credit Carryforward, Amount						$ 4,300,000		$ 4,300,000
Canada, France, and United Kingdom [Member]
Number of Foreign Subsidiaries					3		3
Delphax [Member]
Business Acquisition, Percentage of Voting Interests Acquired			38.00%
Payments to Acquire Businesses, Gross			$ 1,050,000
Contrail Aviation Inc. [Member] | Contrail Aviation Support LLC. [Member]
Business combination, Equity Interests in Acquiree, Percentage		21.00%
Business Combination, Equity Interest in Acquiree, Deemed to be Acquired, Percentage		79.00%
Payments to Acquire Businesses, Gross		$ 4,033,367
Acquired Inventory and Principal Business Assets, and Assumed Specified Liabilities, of Aircraft Instrument and Radio Company, Incorporated, and Aircraft Instrument and Radio Services, Inc. [Member] | AirCo [Member]
Payments to Acquire Businesses, Gross	$ 2,400,000			$ 2,400,000
Business Combination, Bargain Purchase, Gain Recognized, Amount	$ 779,880
Deferred Tax Liabilities, Net					$ 278,000		$ 278,000
Deferred Income Tax Expense (Benefit)							278,000
Business Combination, Bargain Purchase, Gain Recognized, Amount, Net							$ 502,000