CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Jan. 31, 2012	Jan. 31, 2011
Cash flows from operating activities:
Net loss	$ (170)	$ (205)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	102	87
Warranty reserve expense	131	21
Write-off of patent	0	12
Changes in operating assets and liabilities:
Accounts receivable	(906)	(383)
Costs and estimated earnings in excess of billings on uncompleted contracts	(18)	804
Deferred cost of revenue	110	(63)
Inventories	(1,803)	222
Other current and noncurrent assets	(96)	62
Accounts payable	843	(323)
Billings in excess of costs and estimated earnings on uncompleted contracts	652	(49)
Accrued payroll and related taxes	129	89
Warranty reserves	(16)	(34)
Payable to Parent	1	0
Other current and long-term liabilities	(23)	21
Deferred revenues	660	141
Net cash provided by (used in) operating activities	(404)	402
Cash flows from investing activities:
Purchases of certificates of deposit	(500)	(997)
Proceeds from redemption of certificates of deposit	499	1,495
Additions to equipment, furniture and fixtures	(106)	(150)
Additions to patent	0	(2)
Net cash provided by (used in) investing activities	(107)	346
Net increase (decrease) in cash and cash equivalents	(511)	748
Cash and cash equivalents at beginning of period	3,881	2,363
Cash and cash equivalents at end of period	$ 3,370	$ 3,111

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Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents. Includes cash and cash equivalents associated with the entity's continuing operations. Excludes cash and cash equivalents associated with the disposal group (and discontinued operation).