CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ 1,299	$ (170)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation	133	102
Warranty reserve expense	75	131
Changes in operating assets and liabilities:
Accounts receivable	(116)	(906)
Costs and estimated earnings in excess of billings on uncompleted contracts	666	(18)
Deferred cost of revenue	3	110
Inventories	1,089	(1,803)
Other assets	(215)	(96)
Accounts payable	(845)	843
Billings in excess of costs and estimated earnings on uncompleted contracts	0	652
Accrued payroll and related taxes	94	129
Warranty reserves	(137)	(16)
Payable to Parent	0	1
Other liabilities	(33)	(23)
Deferred revenues	1,721	660
Net cash provided by (used in) operating activities	3,734	(404)
Cash flows from investing activities:
Purchases of certificates of deposit	0	(500)
Proceeds from redemption of certificates of deposit	250	499
Additions to equipment, furniture and fixtures	(217)	(106)
Net cash provided by (used in) investing activities	33	(107)
Net increase (decrease) in cash and cash equivalents	3,767	(511)
Cash and cash equivalents at beginning of period	2,783	3,881
Cash and cash equivalents at end of period	6,550	3,370
Supplemental cash flow information:
Cash paid for income taxes	$ 43	$ 0