The following tables reflect the components of significant balance sheet accounts as of March 31, 2018 and September 30, 2017:



	As of
(in thousands)	March 31, 2018			September 30, 2017

Short term investments, available-for-sale⁽¹⁾	$	288,000		$	216,000

Inventories, net:
Raw materials and supplies	$	55,993		$	44,239
Work in process	47,460			40,827
Finished goods	40,646			61,596
	144,099			146,662
Inventory reserves	(25,268		)	(24,639		)
	$	118,831		$	122,023
Property, plant and equipment, net:
Land	$	2,182		$	2,182
Buildings and building improvements	51,160			50,910
Leasehold improvements	9,288			9,882
Data processing equipment and software	34,952			34,700
Machinery, equipment, furniture and fixtures	78,114			68,143
	175,696			165,817
Accumulated depreciation	(100,077		)	(98,055		)
	$	75,619		$	67,762
Accrued expenses and other current liabilities:
Wages and benefits	$	31,168		$	47,411
Accrued customer obligations ⁽²⁾	30,968			52,460
Commissions and professional fees	7,536			8,555
Deferred rent	1,908			1,930
Severance ⁽³⁾	1,217			3,828
Other	12,336			10,663
	$	85,133		$	124,847


(1)	All short-term investments were classified as available-for-sale and were measured at fair value based on level one measurement, or quoted market prices, as defined by ASC 820. The Company did not recognize any realized gains or losses on the sale of investments during the three and six months ended March 31, 2018 and April 1, 2017.


(2)	Represents customer advance payments, customer credit program, accrued warranty expense and accrued retrofit obligations.


(3)	Includes the restructuring plan discussed in Note 3, severance payable in connection with the November 2017 departure of the Company's CFO of $0.7 million, and other severance payments.