Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net loss	$ (26,690)	$ (178,813)
Adjustments to reconcile net loss to cash flows from operating activities:
Gain from sale of Priority Review Voucher	(125,000)
Depreciation and amortization	5,968	3,947
(Accretion of discount) amortization of premium on available-for- sale securities and non-cash interest	(144)	473
Loss on disposal of assets	792	45
Stock-based compensation	23,099	23,093
Non-cash restructuring expenses		504
Changes in operating assets and liabilities, net:
Net increase in accounts receivable	(19,523)	(9)
Net increase in inventory	(51,880)	(2,921)
Net increase in other assets	(7,319)	(8,203)
Net decrease in accounts payable, accrued expenses, deferred revenue and other liabilities	(241)	(2,703)
Net cash used in operating activities	(200,938)	(164,587)
Cash flows from investing activities:
Purchase of property and equipment	(8,101)	(2,427)
Purchase of intangible assets	(8,591)	(1,093)
Purchase of available-for-sale securities	(100,348)
Proceeds from sale of Priority Review Voucher	125,000
Maturity of restricted investment	10,695
Maturity and sale of available-for-sale securities	296,225	112,101
Net cash provided by investing activities	314,880	108,581
Cash flows from financing activities:
Proceeds from July 2017 Term Loan (defined in Note 12), net of cash debt issuance costs	29,620
Proceeds from revolving line of credit	24,000
Payments on June 2015 Term Loan (defined in Note 12) and mortgage loans	(15,081)	(5,076)
Payments on revolving line of credit	(23,008)
Proceeds from sales of common stock, net of offering costs	353,959	364,951
Proceeds from exercise of options and purchase of stock under the Employee Stock Purchase Program	11,779	10,967
Net cash provided by financing activities	381,269	370,842
Increase in cash and cash equivalents	495,211	314,836
Cash, cash equivalents and restricted cash:
Beginning of period	122,556	80,440
End of period	617,767	395,276
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	924	1,199
Supplemental schedule of non-cash investing activities and financing activities:
Shares withheld for taxes	1,791	1,955
Intangible assets included in accrued expenses	258	1,230
Reclassification of software licenses	204
Property and equipment reclassified to asset held for sale	1,529
Accrual for debt issuance costs related to the term loans	600	400
Accrual for offering costs related to equity offerings	25	$ 222
Property and equipment included in accrued expenses	$ 385