SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Sep. 30, 2018

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]

Allowance for Doubtful Accounts

Our allowance for doubtful accounts changed during the fiscal year ended September 30, 2018 as follows:

Balance as of September 30, 2017	$	1,747
Amounts charged to expense		185
Deductions and adjustments		(32	)
Balance as of September 30, 2018	$	1,900

Customers Representing More than Ten Percent of Total Revenue

Customers who represented more than 10% of revenue are as follows:

	Year Ended September 30,
	2018	2017	2016
Samsung Group (Samsung)	18%	16%	15%
Taiwan Semiconductor Manufacturing Co. (TSMC)	12%	13%	15%
SK Hynix Inc.	10%	*	*
Micron Technology Inc.	*	10%	*

* Not a customer with more than 10% revenue.

Property, Plant and Equipment Useful Lives

Property, plant and equipment are recorded at cost. Depreciation is based on the following estimated useful lives of the assets using the straight-line method:

Buildings	15-25 years
Machinery and equipment	3-10 years
Furniture and fixtures	5-10 years
Information systems	3-5 years
Assets under capital leases	Term of lease or estimated useful life