3. Composition of Certain Financial Statement Captions

The following tables present detailed information from our consolidated balance sheets as of June 29, 2018 and September 29, 2017 (amounts displayed in thousands, except as otherwise noted).

Accounts Receivable



	June 29, 2018			September 29, 2017
Trade accounts receivable	$	131,916		$	62,305
Accounts receivable from patent administration program customers	23,288			14,412
Accounts receivable, gross	155,204			76,717
Less: allowance for doubtful accounts	(5,622		)	(2,967		)
Total	$	149,582		$	73,750

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

Inventories



	June 29, 2018		September 29, 2017
Raw materials	$	4,202	$	6,812
Work in process	4,566		4,954
Finished goods	15,164		13,285
Total	$	23,932	$	25,051

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. In addition to the amounts shown in the table above, we have included $3.5 million and $1.8 million of inventory within other non-current assets in our consolidated balance sheets as of June 29, 2018 and September 29, 2017, respectively. We write-down inventory at the time it is deemed excess or obsolete.

Prepaid Expenses And Other Current Assets



	June 29, 2018		September 29, 2017
Prepaid expenses	$	17,941	$	16,681
Other current assets	14,079		11,383
Income tax receivable	652		2,444
Total	$	32,672	$	30,508

Accrued Liabilities



	June 29, 2018		September 29, 2017
Accrued royalties	$	2,764	$	2,274
Amounts payable to patent administration program partners	49,926		49,141
Accrued compensation and benefits	74,157		92,277
Accrued professional fees	7,632		5,530
Unpaid PP&E additions	13,130		10,096
Other accrued liabilities	49,467		47,716
Total	$	197,076	$	207,034

Other Non-Current Liabilities



	June 29, 2018		September 29, 2017
Supplemental retirement plan obligations	$	3,220	$	2,928
Non-current tax liabilities	188,027		91,013
Other liabilities	12,566		13,573
Total	$	203,813	$	107,514