Accrued liabilities as of October 31, 2018 and 2017 consisted of the following (in thousands):

	2018		2017
Accrued payroll and employee benefits	$	2,550	$	5,315
Accrued contract loss		—		37
Accrued product warranty costs ⁽¹⁾		147		348
Accrued material purchases ⁽²⁾		—		2,396
Accrued service agreement costs ⁽³⁾		2,029		3,319
Contractual milestone billings for inventory ⁽⁴⁾		—		4,440
Accrued legal, taxes, professional and other		2,906		2,526
	$	7,632	$	18,381

(1)

Activity in the accrued product warranty costs for the years ended October 31, 2018 and 2017 included additions for estimates of future warranty obligations of $0.4 million and $0.6 million, respectively, on contracts in the warranty period and reductions related to actual warranty spend of $0.6 million and $0.8 million, respectively, as contracts progress through the warranty period or are beyond the warranty period.

(2)

The Company acts as a procurement agent for POSCO Energy under an Integrated Global Supply Chain Agreement whereby the Company procures materials on POSCO Energy’s behalf for its Asian production facility. This liability represents amounts received for the purchase of materials on behalf of POSCO Energy. Amounts due to vendors are recorded as “Accounts payable.”

(3)

Activity in service agreement costs represents a decrease in loss accruals on service contracts of $0.2 million from $1.1 million as of October 31, 2017 to $0.9 million as of October 31, 2018. The accruals for performance guarantees also decreased from $2.2 million as of October 31, 2017 to $1.1 million as of October 31, 2018 resulting from guarantee payments to customers partially offset by additional accruals for the minimum output falling below the contract requirements for certain service agreements.

(4)	Amount represented contractual milestone billings for inventory that was provided to POSCO Energy under a transaction that did not result in revenue recognition.