Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net loss	$ (68,203)	$ (128,632)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	7,518	8,831
Amortization of acquired intangible asset	4,278
Share-based compensation expense	21,836	18,969
Change in fair value of note hedge warrants	44,793	(7,873)
Change in fair value of convertible note hedges	(50,836)	19,421
Write-down of inventory to net realizable value and loss on non-cancellable purchase commitments		17,638
Loss on facility subleases	3,480
Accretion of discount/premium on investment securities	561	722
Non-cash interest expense	10,981	4,599
Non-cash change in fair value of contingent consideration	8,667
Changes in assets and liabilities:
Accounts receivable and related party accounts receivable	803	(11,132)
Restricted cash	500	(600)
Prepaid expenses and other current assets	(2,923)	2,722
Other assets	1,670	(181)
Accounts payable, related party accounts payable and accrued expenses	16,301	(2,946)
Accrued research and development costs	3,797	(939)
Deferred revenue	(4,862)	(5,393)
Deferred rent	(5,108)	(2,774)
Net cash used in operating activities	(6,747)	(87,568)
Cash flows from investing activities:
Purchases of available-for-sale securities	(163,229)	(252,865)
Sales and maturities of available-for-sale securities	203,986	212,018
Purchases of property and equipment	(3,008)	(3,256)
Payment for acquisition of lesinurad license	(100,000)
Proceeds from sale of property and equipment	1	37
Net cash used in investing activities	(62,250)	(44,066)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes		335,699
Costs associated with issuance of 2026 notes	(200)
Proceeds from issuance of note hedge warrants		70,849
Purchase of convertible note hedges		(91,915)
Costs associated with issuance of convertible senior notes		(11,682)
Proceeds from exercise of stock options and employee stock purchase plan	10,553	11,874
Payments on capital leases	(1,243)	(964)
Principal payments on PhaRMA notes	(18,463)	(8,447)
Net cash (used in) provided by financing activities	(9,353)	305,414
Net (decrease) increase in cash and cash equivalents	(78,350)	173,780
Cash and cash equivalents, beginning of period	261,287	74,297
Cash and cash equivalents, end of period	182,937	$ 248,077
Non-cash investing activities:
Contingent consideration	$ 96,260