NOTE 8. OTHER BALANCE SHEET ITEMS

(a) Property and Equipment, Net

Property and equipment, net, consisted of the following:

	March 31, 2016			December 31, 2015
Leasehold improvements	$	22,615		$	19,074
Build-to-suit property		18,371			18,371
Computer equipment and software		17,300			16,083
Furniture and fixtures		6,014			5,714
Construction in progress		12,806			14,440
Laboratory equipment		1,447			748
		78,553			74,430
Less: Accumulated depreciation		(18,704	)		(16,288	)
Total	$	59,849		$	58,142

(b) Accounts Payable, Accrued Expenses and Other Current Liabilities

Accounts payable, accrued expenses and other current liabilities consisted of the following:

	March 31, 2016		December 31, 2015
Clinical and preclinical	$	45,635	$	48,975
Accounts payable		23,791		22,696
Payroll and payroll-related		15,988		29,215
Royalties payable		21,015		20,665
Accrued professional services and other current liabilities		15,566		14,282
Taxes payable		—		32,565
Other payable to licensor		—		17,500
Interest payable		—		305
Total	$	121,995	$	186,203

Accounts payable represents short-term liabilities for which the Company has received and processed a vendor invoice prior to the end of the reporting period. Accrued expenses and other current liabilities represent, among other things, compensation and related benefits to employees, royalties due to licensors of technologies, estimated amounts due to third-party vendors for services rendered prior to the end of the reporting period, invoices received from third-party vendors that have not yet been processed, taxes payable, interest payable and other accrued items.