C. DETAIL OF SELECTED BALANCE SHEET ACCOUNTS

Allowance for Doubtful Accounts

Activity in our allowance for doubtful accounts receivable consisted of the following (in thousands):

	Three Months Ended						Nine Months Ended
	June 30,						June 30,
	2014			2013			2014			2013
Balance at beginning of period	$	501		$	818		$	572		$	1,297
Bad debt expense/(recovery)		676			20			616			(310	)
Uncollectible accounts written off, net of recoveries		(38	)		(19	)		(46	)		(156	)
Change in foreign currency translation		5			(2	)		2			(14	)
Balance at end of period	$	1,144		$	817		$	1,144		$	817

Inventories:

The components of inventories are summarized below (in thousands):

	June 30,			September 30,
	2014			2013
Raw materials, parts and subassemblies	$	31,484		$	30,077
Work-in-progress		1,551			3,818
Provision for excess and obsolete inventory		(4,326	)		(4,932	)
Total inventories	$	28,709		$	28,963

Cost and Estimated Earnings on Uncompleted Contracts

The components of costs and estimated earnings and related amounts billed on uncompleted contracts are summarized below (in thousands):

	June 30,			September 30,
	2014			2013
Costs incurred on uncompleted contracts	$	709,561		$	618,570
Estimated earnings		182,506			159,962
		892,067			778,532
Less: Billings to date		(842,322	)		(747,446	)
Net underbilled position	$	49,745		$	31,086

Included in the accompanying balance sheets under the following captions:
Costs and estimated earnings in excess of billings on uncompleted contracts – underbilled	$	83,999		$	79,420
Billings in excess of costs and estimated earnings on uncompleted contracts – overbilled		(34,254	)		(48,334	)
Net underbilled position	$	49,745		$	31,086

Warranty Accrual

Activity in our product warranty accrual consisted of the following (in thousands):

	Three Months Ended						Nine Months Ended
	June 30,						June 30,
	2014			2013			2014			2013
Balance at beginning of period	$	4,833		$	5,109		$	5,282		$	5,548
Increase to warranty expense		884			430			2,390			2,048
Deduction for warranty charges		(1,023	)		(874	)		(2,949	)		(2,849	)
Increase (decrease) due to foreign currency translations		61			(10	)		32			(92	)
Balance at end of period	$	4,755		$	4,655		$	4,755		$	4,655