DETAIL OF SELECTED BALANCE SHEET ACCOUNTS (Tables)

6 Months Ended

Mar. 31, 2018

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



	Three months ended March 31,						Six months ended March 31,
	2018			2017			2018			2017
Balance at beginning of period	$	158		$	664		$	179		$	811
Bad debt expense (recovery)	112			16			92			(97		)
Uncollectible accounts written off, net of recoveries	(7		)	(373		)	(8		)	(400		)
Change due to foreign currency translation	1			3			1			(4		)
Balance at end of period	$	264		$	310		$	264		$	310

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



	March 31, 2018		September 30, 2017
Raw materials, parts and subassemblies, net	$	21,059	$	17,848
Work-in-progress	953		600
Total inventories	$	22,012	$	18,448

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



	March 31, 2018			September 30, 2017
Costs incurred on uncompleted contracts	$	988,433		$	987,164
Estimated earnings	313,031			316,970
	1,301,464			1,304,134
Less: Billings to date	(1,286,178		)	(1,278,746		)
Net underbilled position	$	15,286		$	25,388
Included in the accompanying balance sheets under the following captions:
Costs and estimated earnings in excess of billings on uncompleted contracts	$	44,008		$	51,554
Billings in excess of costs and estimated earnings on uncompleted contracts	(28,722		)	(26,166		)
Net underbilled position	$	15,286		$	25,388

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



	Three months ended March 31,						Six months ended March 31,
	2018			2017			2018			2017
Balance at beginning of period	$	2,890		$	4,230		$	3,174		$	4,639
Increase (decrease) in warranty expense	(261		)	349			(66		)	719
Deduction for warranty charges	(383		)	(944		)	(861		)	(1,669		)
Change due to foreign currency translation	(5		)	14			(6		)	(40		)
Balance at end of period	$	2,241		$	3,649		$	2,241		$	3,649