4. Balance sheet components

Accounts Receivable, Net of allowances—Accounts receivable, net of allowances, consisted of the following (in thousands):

	September 30, 2018			December 31, 2017
Gross accounts receivable	$	146,156		$	138,292
Allowance for sales returns		(4,221	)		(6,907	)
Allowance for sales incentives		(7,271	)		(10,442	)
Other allowances		(769	)		(390	)
Total allowances		(12,261	)		(17,739	)
Total Accounts Receivable—net of allowances	$	133,895		$	120,553

Allowance for Sales Returns—Allowance for sales returns consisted of the following activities (in thousands):

	September 30, 2018			December 31, 2017
Beginning balance	$	(6,907	)	$	(6,916	)
Charged to revenue		(10,239	)		(19,089	)
Utilization of sales return reserve		12,925			19,098
Ending balance	$	(4,221	)	$	(6,907	)

Allowance for Sales Incentives—Allowance for sales incentives consisted of the following activities (in thousands):

	September 30, 2018			December 31, 2017
Beginning balance	$	(10,442	)	$	(8,503	)
Charged to revenue		(24,017	)		(44,264	)
Utilization of sales incentive reserve		27,188			42,325
Ending balance	$	(7,271	)	$	(10,442	)

Property and Equipment, Net—Property and equipment, net consisted of the following (in thousands):

	September 30, 2018			December 31, 2017
Computers and equipment	$	14,870		$	11,631
Leasehold improvements		16,615			8,437
Website and internal-use software		6,745			5,461
Office equipment and furniture		3,099			1,987
Total property and equipment		41,329			27,516
Accumulated depreciation and amortization		(18,069	)		(12,780	)
Property and Equipment, net	$	23,260		$	14,736

Depreciation and amortization expense for the three months ended September 30, 2018 and 2017 was $2.1 million and $1.3 million, respectively. Depreciation and amortization expense for the nine months ended September 30, 2018 and 2017 was $5.4 million and $3.9 million, respectively.

Accounts Payable and Accrued Liabilities—Accounts payable and accrued liabilities consisted of the following (in thousands):

	September 30, 2018		December 31, 2017
Accounts payable	$	55,298	$	56,413
Accrued royalty expense		6,182		17,165
Accrued inventory		22,857		2,382
Accrued payroll and related expenses		7,195		8,699
Accrued cost of revenue		15,628		12,210
Accrued payments to content publishers		28,815		24,037
Taxes and related liabilities		1,135		1,463
Customer prepayments		2,951		545
Other accrued expenses		7,194		5,843
Total Accounts Payable and Accrued Liabilities	$	147,255	$	128,757

Deferred Revenue—Deferred revenue consisted of the following (in thousands):

	September 30, 2018		December 31, 2017
Platform, current	$	23,681	$	19,022
Player, current		14,862		15,479
Total deferred revenue, current		38,543		34,501
Platform, non-current		8,300		42,674
Player, non-current		5,076		5,837
Total deferred revenue, non-current		13,376		48,511
Total Deferred Revenue (See Note 12)	$	51,919	$	83,012