11. Acquisition of Elcom Technologies, Inc. (Details) (USD $)	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
11. Acquisition of Elcom Technologies, Inc. (Details) [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent	$ 0	$ 2,573,000
Business Acquisition Purchase Price Allocation Intangible Assets and Goodwill	0	673,000
Gain (Loss) on Investments	0	730,000
Revenues	68,932,000	63,595,000
Common Stock Shares [Member]
11. Acquisition of Elcom Technologies, Inc. (Details) [Line Items]
Payments to Acquire Businesses, Gross		4,100,000
Certain Selling Shareholders to Settle Debt [Member] | FEI-Elcom [Member]
11. Acquisition of Elcom Technologies, Inc. (Details) [Line Items]
Payments to Acquire Businesses, Gross		910,000
Elcom Technologies Inc [Member]
11. Acquisition of Elcom Technologies, Inc. (Details) [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage		74.88%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		25.12%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		4,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent		2,600,000
Business Acquisition Purchase Price Allocation Intangible Assets and Goodwill		700,000
Goodwill		400,000
Gain (Loss) on Investments		730,000
Other Asset Impairment Charges		350,000
Professional Fees		16,000
Sales Revenue, Goods, Net		5,000
Interest Income, Related Party		87,000
Business Combination, Acquisition Related Costs		230,000
Revenues		840,000
Income (Loss) Attributable to Noncontrolling Interest		700,000
FEI-Elcom [Member]
11. Acquisition of Elcom Technologies, Inc. (Details) [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Business Combination Consideration Transferre Forgiveness of Debt		1,700,000
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value		7,900,000
Fair Value Inputs, Control Premium		15.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		275,000
Goodwill		$ 398,000