Detail of Selected Balance Sheet Accounts (Tables)

6 Months Ended

Mar. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Activity in Allowance for Doubtful Accounts Receivable

Activity in our allowance for credit losses consisted of the following (in thousands):

	Three months ended March 31,				Six months ended March 31,
	2021		2020		2021		2020
Balance at beginning of period	$	493	$	346	$	510	$	301
Bad debt expense (recovery), net	(113)		9		(132)		51
Uncollectible accounts written off, net of recoveries	—		(45)		(10)		(55)
Change due to foreign currency translation	2		(10)		14		3
Balance at end of period	$	382	$	300	$	382	$	300

Components of Inventories

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

	March 31, 2021		September 30, 2020
Raw materials, parts and sub-assemblies, net	$	29,302	$	27,429
Work-in-progress	729		1,539
Total inventories	$	30,031	$	28,968

Activity in Product Warranty Accrual

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

	Three months ended March 31,				Six months ended March 31,
	2021		2020		2021		2020
Balance at beginning of period	$	2,675	$	3,162	$	2,771	$	2,946
Increase to warranty expense	395		784		1,053		1,627
Deduction for warranty charges	(609)		(670)		(1,388)		(1,315)
Change due to foreign currency translation	6		—		31		18
Balance at end of period	$	2,467	$	3,276	$	2,467	$	3,276