4. Composition of Certain Financial Statement Captions

The following tables present detailed information from our consolidated balance sheets as of December 28, 2018 and September 28, 2018 (amounts displayed in thousands, except as otherwise noted).

Accounts Receivable



	December 28, 2018			September 28, 2018 (as adjusted)
Trade accounts receivable	$	115,333		$	108,929
Accounts receivable from patent administration program licensees	73,141			97,262
Accounts receivable, gross	188,474			206,191
Less: allowance for doubtful accounts	(6,860		)	(5,258		)
Total	$	181,614		$	200,933

Trade accounts receivable includes unbilled accounts receivable balances related to amounts that are contractually owed.

Inventories



	December 28, 2018		September 28, 2018
Raw materials	$	8,087	$	6,095
Work in process	4,116		4,044
Finished goods	15,562		16,067
Total	$	27,765	$	26,206

Inventories are stated at the lower of cost and net realizable value. Inventory with a consumption period expected to exceed twelve months is recorded within other non-current assets in our consolidated balance sheets. We have included $3.0 million and $2.6 million of raw materials inventory within other non-current assets in our consolidated balance sheets as of December 28, 2018 and September 28, 2018, respectively. Based on anticipated inventory consumption rates, and aside from existing write-downs due to excess inventory, we do not believe that material risk of obsolescence exists prior to ultimate sale.

Prepaid Expenses And Other Current Assets



	December 28, 2018		September 28, 2018 (as adjusted)
Prepaid expenses	$	22,316	$	18,508
Other current assets	14,936		13,946
Income tax receivable	2,349		2,436
Total	$	39,601	$	34,890

Accrued Liabilities



	December 28, 2018		September 28, 2018 (as adjusted)
Accrued royalties	$	3,257	$	2,648
Amounts payable to patent administration program partners	75,458		98,900
Accrued compensation and benefits	56,662		84,491
Accrued professional fees	14,252		9,749
Unpaid PP&E additions	20,253		13,956
Other accrued liabilities	95,209		63,223
Total	$	265,091	$	272,967

Other Non-Current Liabilities



	December 28, 2018		September 28, 2018
Supplemental retirement plan obligations	$	3,190	$	3,388
Non-current tax liabilities	133,322		129,253
Other liabilities	19,894		18,319
Total	$	156,406	$	150,960