Other Balance Sheet Information (Tables)

6 Months Ended

Mar. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of Accounts Receivable

The following is a summary of accounts receivable at March 31, 2018 and September 30, 2017 (in thousands):

	March 31,		September 30,
	2018		2017
Accounts receivable	$	142,819	$	122,868
Less allowance for doubtful accounts		(1,266)		(1,959)
Less allowance for sales returns		(52)		(81)
Accounts receivable, net	$	141,501	$	120,828

Summary of Inventories

The following is a summary of inventories at March 31, 2018 and September 30, 2017 (in thousands):

	March 31,		September 30,
	2018		2017
Inventories
Raw materials and purchased parts	$	79,633	$	73,819
Work-in-process		17,503		10,548
Finished goods		29,458		22,028
Total inventories	$	126,594	$	106,395

Product Warranty and Retrofit Activity on Gross Basis

The following is a summary of product warranty and retrofit activity on a gross basis for the three and six months ended March 31, 2018 and 2017 (in thousands):

Activity -Three Months Ended March 31, 2018
Balance						Balance
December 31,						March 31,
2017		Accruals		Costs Incurred		2018
$	8,218	$	2,073	$	(2,002)	$	8,289

Activity -Three Months Ended March 31, 2017
Balance						Balance
December 31,						March 31,
2016		Accruals		Costs Incurred		2017
$	6,217	$	2,709	$	(1,853)	$	7,073

Activity -Six Months Ended March 31, 2018
Balance						Balance
September 30,						March 31,
2017		Accruals		Costs Incurred		2018
$	8,054	$	4,409	$	(4,174)	$	8,289

Activity -Six Months Ended March 31, 2017
Balance						Balance
September 30,						March 31,
2016		Accruals		Costs Incurred		2017
$	6,324	$	5,216	$	(4,467)	$	7,073