Trade accounts receivable, net (excluding notes receivable) are reflected in the following table (in thousands):


	December 31, 2022			September 30, 2022
Trade accounts receivable	$	24,629		$	13,252
Allowance for doubtful accounts		(689	)		(591	)
Total	$	23,940		$	12,661

The allowance for doubtful accounts represents the Company’s best estimate of probable credit losses. The Company determines the allowance based upon historical experience and a current review of its trade accounts receivable balances. Trade accounts receivable balances are charged off against the allowance whenever it is probable that the receivable balance will not be recoverable.

Notes receivable are reflected in the following table (in thousands):


	December 31, 2022			September 30, 2022
Notes receivable	$	7,790		$	8,225
Less current portion		(7,484	)		(8,225	)
Non-current notes receivable	$	306		$	—

Promissory notes receivable are generally collateralized by the products sold, and bear interest at rates ranging from 7.0% to 9.5% per year. The promissory notes receivable mature at various times through January 2024. The Company has, on occasion, extended or renewed notes receivable as they mature, but there is no obligation to do so.

During the second quarter of fiscal year 2022, the Company partially financed a $10.0 million sale of rental equipment by entering into a $8.0 million promissory note with a customer. The note has a one-year term, with principal and interest payments due quarterly until maturity. The balance outstanding on the promissory note at December 31, 2022 was $4.0 million

During the first quarter of fiscal year 2022, the Company financed a sale of rental equipment by entering into a $3.7 million promissory note with a customer. The note has a term of nine months, with principal and interest payments due monthly until maturity. The balance outstanding on the promissory note at December 31, 2022 was $0.8 million. The balance outstanding was paid in January 2023.

During the second quarter of fiscal year 2020, the Company partially financed a $12.5 million product sale by entering into a $10.0 million promissory note with the customer. The note has a three-year term with monthly principal and interest payments of $0.3 million. During the fourth quarter of fiscal year 2021, the Company granted the customer a six-month principal payment forbearance. The customer recommenced its monthly payments to the Company in the second quarter of fiscal year 2022. In October 2022, the Company granted the customer an additional six-month principal payment forbearance. The customer has made payments totaling $9.5 million (exclusive of interest) as of December 31, 2022 related to the product sale, and the balance outstanding on the promissory note at December 31, 2022 was $3.0 million.