Other Balance Sheet Information

The following is a summary of accounts receivable at September 30, 2013 and 2012 (in thousands):



	September 30,
	2013			2012
Accounts receivable	$	78,460		$	79,706
Less allowance for doubtful accounts	(863		)	(851		)
Less allowance for sales returns	(114		)	—
	$	77,483		$	78,855

The allowance for doubtful accounts activity for the years ended September 30, 2013, 2012 and 2011 were as follows (in thousands):



Description	Balance at Beginning of Period		Provisions		Reversals of Bad Debt Expense			Write-offs and Adjustments			Balance at End of Period
2013 Allowance for doubtful accounts	$	851	$	48	$	(143	)	$	107		$	863
2012 Allowance for doubtful accounts	617		367		(130		)	(3		)	851
2011 Allowance for doubtful accounts	491		—		—			126			617

As part of the acquisition of Crossing in fiscal year 2013, the Company acquired a contract in which a certain customer has a right of return on the purchase of spare parts. The allowance for returns activity for the year ended September 30, 2013 was as follows (in thousands):



Description	Balance at Beginning of Period		Provisions		Write-offs and Adjustments		Balance at End of Period
2013 Allowance for sales returns	$	—	$	72	$	42	$	114

The following is a summary of inventories at September 30, 2013 and 2012 (in thousands):



	September 30,
	2013		2012
Inventories
Raw materials and purchased parts	$	60,106	$	64,732
Work-in-process	20,256		20,800
Finished goods	17,357		17,453
	$	97,719	$	102,985

Reserves for excess and obsolete inventory were $24.3 million and $23.2 million at September 30, 2013 and 2012, respectively. The Company recorded charges to reserves for excess and obsolete inventory of $5.4 million, $4.3 million and $2.2 million in fiscal 2013, 2012 and 2011, respectively. The Company reduced the reserves for excess and obsolete inventory by $4.3 million, $5.8 million and $3.5 million, in fiscal 2013, 2012 and 2011, respectively, for disposals of inventory.

The Company provides for the estimated cost of product warranties, primarily from historical information, at the time product revenue is recognized and retrofit accruals at the time retrofit programs are established. The Company’s warranty obligation is affected by product failure rates, utilization levels, material usage, service delivery costs incurred in correcting a product failure, and supplier warranties on parts delivered to the Company. Product warranty and retrofit activity on a gross basis for the years ended September 30, 2013, 2012 and 2011 is as follows (in thousands):



Balance at September 30, 2010	$	8,195
Adjustments for acquisitions and divestitures	698
Accruals for warranties during the year	11,299
Costs incurred during the year	(12,754		)
Balance at September 30, 2011	7,438
Adjustments for acquisitions and divestitures	7
Accruals for warranties during the year	13,751
Costs incurred during the year	(13,867		)
Balance at September 30, 2012	7,329
Adjustments for acquisitions and divestitures	1,187
Accruals for warranties during the year	10,111
Costs incurred during the year	(11,278		)
Balance at September 30, 2013	$	7,349